Rancher's Guide to Managed Grazing

Rancher’s Guide to Managed Grazing in South Dakota Eric M. Mousel

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Rancher’s Guide to Managed Grazing in South Dakota

Eric M. Mousel

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This publication is designed to provide accurate and authoritative information in regard to the subject matter covered. It is sold with the understanding that the publisher is not engaged in rendering legal, accounting, or other professional services. If legal, accounting or other expert assistance is required, the services of a competent professional person should be sought. FROM A DECLARATION OF PRINCIPLES JOINTLY ADOPTED BY A COMMITTEE OF THE AMERICAN BAR ASSOCIATION AND A COMMITTEE OF PUBLISHERS. First printing, 2013 © Copyright 2013 Library of Congress Cataloging-in-Publication Data Mousel, Eric Rancher’s Guide to Managed Grazing in South Dakota/by Eric Mousel p. cm.

ISBN 1. Animal industry—United States Cover Design by Eric Mousel, Brookings, SD Manufactured in the United States of America

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Table of Contents Soils……………………………………………………………………… 5 Understanding how plants grow………………………………………. 14 Forage quality…………………………………………………………... 23 Forage distribution and stocking rates for South Dakota…………… 33 Animal nutrient requirements………………………………………… 45 Matching livestock demand to forage supply………………………… 54 Basic principles of grazing management……………………………… 70 Grazing systems………………………………………………………… 75 Setting grazing goals and selecting a grazing system to meet those goals……………………………………………… 85 Grazing distribution…………………………………………………..... 93 Pasture monitoring……………………………………………………... 100 Managing wildlife habitat with grazing management………………... 108

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Chapter 1 Soils Soils are the foundation of any grazing program. Managing soils, soil organic matter and soil fertility in particular, is the most important part of soil management that the grass manager can have a direct impact on. Understanding and properly managing soil organic matter, hydrology, and fertility will provide the basis for a sustainable grass system from which the foundation of a profitable range livestock business can be built upon.

Soil basics Physical properties of soils Texture and structure  The physical properties of a soil are determined largely by the soil’s texture, or size of the particles, and by its structure, or the arrangement of these particles.  The texture of a soil is determined by the proportions of sand, silt, and clay in it.

The size of the sand grains also helps determine the soil texture.  The more common soil texture names, listed in order of increasing fineness, are: 1. Sand 2. Loamy sand 3. Sandy loam 4. Loam 5. Silt loam 6. Silt 7. Sandy clay loam 8. Clay loam 9. Silty clay loam 10. Sandy clay 11. Silty clay 12. Clay  Figure 1.1 shows the USDA classifications of soil texture.  The grouping of different soil textures into aggregates is called soil structure.

Natural soil aggregates, called peds, are fairly water stable. Peds are classified according to shape, arrangement, size, and degree of distinctness.  Silt soil aggregates have flat, plate-like structures that fit closely together. If they are cemented together by iron oxides, they form a hardpan which water and roots can barely penetrate.

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 Colloids are the very fine separates of soils that do not settle out readily in a water solution. They consist largely of clay or organic matter. If the soil is high in calcium or hydrogen, it will be well aggregated and of good structure. If the soil is high in sodium or potassium, the soil aggregates will be highly dispersed and of poor structure. Soils with good structure have the potential to maintain a higher cation exchange capacity, the primary influencer of overall soil fertility.  Root growth and organic matter have a very positive influence on soil structure.

Freezing and thawing also will break down clods caused by cultivation when the soil is wet.

Figure 1.1. USDA classification of soil texture.

Chemical properties of soils  Plant growth is affected to a large degree by the supply of the major nutrients, nitrogen, phosphorous, and potassium (NPK), and by the lime or calcium content that determines the acidity of the soil.  Although there is some movement of the nutrients through the deep root system to the topsoil, most of the needed nutrients must be supplied by commercial fertilizers.

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 Nitrogen is generally the first limiting nutrient to economical production of grass.

For legumes the first economically limiting nutrient may be phosphorous, potassium, lime, or magnesium. The kind and amount of nutrients that must be added to the soil are determined by a soil test.  The soil pH, or acidity, is very important to economical plant growth. The pH of distilled water is 7 (neutral). If the soil has a pH of 6, this means that it is 10 times as acid as a neutral soil. A soil with a pH of 5 is 10 times as acid as one with a pH of 6. A soil with a pH of 8 is 10 times as basic as a neutral soil with a pH of 7 and so on.  The pH of a soil is important because it affects the solubility or availability of different plant nutrients. Both very acid and very basic conditions may affect the same soil nutrient. Acid soils may reduce the nitrogen fixing ability of legumes.  In general, pasture grasses are more tolerant to acidic conditions than legumes.

Therefore, liming grass pastures to increase pH is generally unnecessary unless the condition is severe. Legumes and grass-legume mixtures, however, may need to be limed if soils have an acidic condition.

Nitrogen  Nitrogen to be used by the plant must be obtained from organic matter, nitrogenfixing bacteria, rainfall, or from commercial fertilizers.  The main sources of nitrogen fertilizers and their nitrogen percentages are: 1) Anhydrous ammonia, 82% N 2) Urea, 46% N 3) Ammonium nitrate, 33.5% N 4) Ammonium sulfate, 21% N 5) Nitrate solutions, 28 to 32% N  Most plants use nitrogen in the nitrate (NO3) form, but some can use the ammonia (NH3) form. The ammonia in fertilizers must be broken down to the nitrate form by soil bacteria before being available to plants.

Minerals Boron  Required by plants in small amounts and is deficient in some soils.  Soils deficient in boron can reduce the longevity of alfalfa stands and can limit legume inoculation.

Calcium

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 Reduces soil acidity, adds strength to plants, and aids in the formation of bones and teeth in animals.  Most of the calcium needed by livestock can be furnished by forage. However, lime must be applied to acid soils to supply the plants with adequate calcium for growth.

Cobalt  Is not essential to plant growth but is an important requirement in ruminant diets.

Most forages contain sufficient cobalt for livestock needs.

Copper  Essential in the enzyme systems of plants it is used in very small amounts and most soils contain enough for plant and animal growth.

Magnesium  A necessary component of chlorophyll, the green substance in plants that facilitates photosynthesis.  Most plants, especially legumes, contain sufficient magnesium to meet the requirements of animals.  Soils that are high in potassium and low in magnesium may increase the incidence of grass tetany, particularly in lush, rapidly growing forages. This disease can be controlled by feeding livestock extra magnesium or growing legumes in the pasture.

Manganese  Required in small amounts by plants and animals. Too much in the soil will reduce iron availability to plants.  Soils that are very basic or over-limed may be deficient in available manganese.

Iodine  Found in plants and is important in the function of the thyroid gland in animals.

Iodine is commonly deficient in soils in the Midwest and Upper Great Plains.  The simplest method of furnishing iodine to animals is to feed iodized salt.

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Iron  Most soils contain sufficient available iron unless it is tied up in very basic soils.

The addition of sulfur will increase the availability of iron.  Necessary for the formation of chlorophyll in plants and hemoglobin in animals.

Phosphorous  Phosphorous is needed for grass and legume growth and for nitrogen fixation by bacteria. It also is essential to animal growth and must be supplied in the forage or in mineral mixtures.  Most plants use phosphorous in the H2PO4 form, but the phosphorous content of commercial fertilizers is usually measured in the P2O5 form.  The main sources of phosphorous in commercial fertilizers and their normal percentage of P2O5 are: 1) Superphosphate, 20% P2O5 2) Triple phosphate, 45% P2O5 3) Rock phosphate, 41% P2O5  Other sources of phosphorous also contain nitrogen: 1) Diammonium phosphate, 53% P2O5 and 21% N 2) Monoammonium phosphate, 48% P2O5 and 11% N 3) Ammonium phosphate sulfate, 20% P2O5 and 16% N  Phosphorous does not leach out of the soil profile readily and will gradually build up from continued applications in excess of plant use.

Potassium  Potassium is an essential plant nutrient that makes plants more resistant to plant diseases, insects, cold weather, and drought.  Soil potassium needs are greatly increased when forage crops are removed as hay or silage. Under grazing conditions, some potassium is returned to the soil in both manure and urine.  Legumes and grasses are both heavy users of potassium, especially grasses because of their extensive, fibrous root system. Extra potassium must be applied to grass-legume mixtures in order to supply the needs of the legumes.  The main sources of fertilizer potassium and their percentage of K2O are:

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1) Muriate of potash, 60% K2O 2) Sulfate of potash, 51% K2O 3) Sulfate of potash (magnesia), 22% K2O with 18% MgO Sodium and chlorine  Usually provided by salt, are necessary for animal growth but not plant growth.  Too much salt will adversely affect soil structure and will greatly reduce plant growth.

Sulfur  Increases root growth and helps maintain dark green color in the leaf tissue of plants.  Sulfur is used by the plant for protein formation and nitrogen fixation by legumes.  Most of the sulfur needed by plants comes from the air or from organic matter.

Amending soils with sulfur is rarely necessary in the northern plains.

Zinc  Needed by plants only in small amounts and is usually available in most soils.  Zinc deficiency is indicated by white or striped leaves.

Soil organic matter (SOM)  Soil organic matter includes the total organic compounds in soils and is composed of a mixture of plant and animal residues in different stages of decomposition, substances synthesized microbiologically and/or chemically from the breakdown products, and the bodies of live and dead microorganisms and their decomposing remains.  Soil organic matter contents range from 0.5 to 5% on a weight basis in the surface horizon of mineral soils to 100% in organic soils (e.g., peat, muck, etc.). In soils of the prairie regions, SOM may be as high as 5% while in sandy soils the content is often < 1%.  Soil organic matter is important because it improves soil structure, moisture holding capacity, aeration, and aggregation.  It also is an important reservoir of macronutrients such as N, P, and S and micronutrients such as B and Mo. It also contains large quantities of C, which provides an energy source for soil macroflora and microflora.

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 Cation exchange capacity (CEC) reflects the ability of a soil to supply available nutrients to plants. Soil organic matter has a very high influence on CEC of a soil.  Managing SOM through proper soil fertility management and grazing management that considers soil and vegetation type is critical to maintaining productive and sustainable vegetation systems.

Figure 1.2. Effect of residual vegetation cover on subsequent years’ grass production (adapted from Bartolome et al., 2007 and Willms et al., 1986).

Infiltration  Infiltration is governed by two forces: gravity and capillary action. While smaller pores offer greater resistance to gravity, very small pores pull water through capillary action in addition to and even against the force of gravity.  The maximum rate at which water can enter a soil in a given condition is the infiltration capacity. If the arrival of the water at the soil surface is less than the infiltration capacity, all of the water will infiltrate. The rate of infiltration is affected by soil characteristics including ease of entry, storage capacity, and transmission rate through the soil.  Once water has infiltrated the soil it remains in the soil, percolates down to the ground water table, or becomes part of the subsurface runoff process.  The process of infiltration can continue only if there is room available for additional water at the soil surface. The available volume for additional water in the soil depends on the porosity of the soil and the rate at which previously infiltrated water can move away from the surface through the soil.

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 If rainfall intensity at the soil surface occurs at a rate that exceeds the infiltration capacity, ponding begins and is followed by runoff over the ground surface, once depression storage is filled.  The soil texture and structure, vegetation types and cover, water content of the soil, soil temperature, and rainfall intensity all play a role in controlling infiltration rate and capacity.  Therefore, moisture infiltration and grass production are part of a larger positive feedback loop where increased residual vegetation cover at the end of the grazing season results in increased grass production because of improved infiltration hydrology.  Figure 1.2 shows how increased moisture infiltration increases grass production.  Although environmental factors have a huge impact, grass production can be managed through managing the amount of residual vegetation cover in pastures during and after the growing season.

Soil fertility testing  In order to obtain a good working knowledge of the soil, various different soils should be tested, as well as different fields and pastures, on the farm or ranch.

These tests should be performed every three to five years to monitor and amend changes in soil acidity and plant nutrient content.  Basic (and inexpensive) soil tests will provide the baseline concentrations of organic matter, N, P, K, Ca, and soil acidity or pH. Additional soil chemical properties can be tested; however, these soil tests cost substantially more and provide little additional value to the manager.  Soil amendment recommendations are then based upon these tests in relation to the crop that will be grown in the current growing season.  Soil samples should be taken at 15 to 20 locations in each management unit.  The soil test is no better than the quality of sample taken, so take lots of small samples over the entire management unit.  The samples can be taken with a soil probe, spade, or shovel (Figure 1.3). Take a ½-inch slice of a soil to a depth of 6 to 9 inches for the topsoil sample and take subsoil samples to a depth of 18 to 24 inches.  Collect these small samples in separate containers. Mix each container thoroughly and take out about ½ pint of topsoil and ½ pint of subsoil to send to a test laboratory.

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Figure 1.3. Sampling soils in a pasture. Photo by Alexander Smart.

References Bartolome, J.W., R. D. Jackson, A. D. K. Betts, J. M. Connor, G. A. Nader and K. W. Tate. 2007. Effects of residual dry matter on net primary production and plant functional groups in Californian annual grasslands. Grass and Forage Science.

62:445-452.

Willms, W.D., S. Smoliak, and A.W. Bailey. 1986. Standing crop following litter removal on Alberta native grasslands. Journal of Range Management. 39:536-540.

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Chapter 2 Understanding How Plants Grow The first step to successful management practices on pastures and rangeland is a basic understanding of plant growth and how plants respond to grazing by livestock.

Different forage species respond differently to defoliation by grazing animals. Both physiological (internal chemical changes) and morphological (external structures) changes as a result of grazing, affects forage quantity, quality and long-term survival of the plant.

When grazing managers are familiar with the basic plant processes of photosynthesis, effects of temperature, carbohydrate synthesis, storage and utilization, grass tiller development, and plant reproduction, they are better equipped to make good grazing management decisions that improve livestock production and sustain long-term pasture and rangeland productivity.

Plant Photosynthesis  Photosynthesis is the basic chemical reaction that occurs in green plants to convert solar energy (from the sun) to chemical energy (carbohydrate sugars) that provide energy for plant growth and maintenance.  Carbon dioxide (CO2) and water (H2O) are the raw materials used by the plant during the photosynthetic process.  During the chemical reaction, CO2 from the air is captured by the plant leaves and water is captured by the plant roots. When CO2 and H2O are both in the presence of green plant material, sunlight will allow the carbon (C) in CO2 (gas) to be incorporated into a newly synthesized carbohydrate (CHO) sugar (solid) via photosynthesis.

Sunlight CO2 + H2O CHO + O2 Green plant material  Certain CHO sugars are then used to provide energy for plant growth and maintenance. Other carbohydrate sugars are further refined and used as the raw materials for building new plant tissues such as cell walls.  When carbohydrate sugars are produced in excess of the plant’s needs, they are refined again into starches which are then stored for later use at various locations within the plant.  Water, another key ingredient for photosynthesis is limiting in most regions of South Dakota. Therefore, the productivity of a plant will depend on how efficiently it can capture CO2 and water to use for photosynthesis.

Cool-season vs. Warm-season

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 Temperature affects both the rate at which CO2 can be captured by the plant and the rate at which CO2 can be converted to energy through photosynthesis.  Cool-season (C3) plants and warm-season (C4) plants have different photosynthetic systems to cope with the type of environment they grow in (Table 2.1). Cool-season plants are of temperate origin and use the C3 photosynthetic system, warm-season plants which have evolved under tropical conditions use the C4 system.  Warm-season grasses initiate growth in late spring, mature in late summer, and become dormant in early fall. Matching livestock use to the season of growth for different grass species can improve forage distribution over the growing season and improve livestock production.

Table 2.1. Examples of cool-season (C3) and warm-season (C4) forage species.

Cool-season (C3) Warm-season (C4) Annual Annual Wheat Corn Rye Sudangrass Oats Forage sorghum Triticale Millets Perennial Smooth bromegrass Kentucky bluegrass Orchardgrass Wheatgrasses Needlegrasses Reed canarygrass Quackgrass

Perennial Big bluestem Indiangrass Switchgrass Little bluestem Prairie and Sand dropseed Sideoats grama Blue grama

 Optimum temperature for growth of C3 plants is between 65 and 75º F although they will grow when temperatures are below 40º F and above 85º F, but at a much slower rate.  Optimum growth for C4 plants occurs at temperatures between 90-95º F. Warmseason plants also will grow when air temperatures are outside of their optimum range (below 75º F and above 100º F), but at a much slower rate.  Because of the C4 photosynthetic system, C4 plants have the potential to be much more productive than C3 plants when water and other nutrients needed for growth are limited.  Warm-season plants use less water to produce a unit of forage than C3 plants. In general, C4 plants are about twice as efficient in water use when compared to C3 plants, which helps to explain why warm-season pastures are more productive in 15

the hot, dry summer months and cool-season pastures are more productive in the cool, moist spring and fall months (Figure 2.1).  Warm-season plants are also more efficient in the utilization of nitrogen. Nitrogen is one of the basic building blocks of plants function and its quantity is limited in most soils of South Dakota.  Warm-season grasses can produce more forage per unit of nitrogen than C3 plants.

Warm-season pastures generally have more soil microbial activity in the summer which increases the availability of recycled nitrogen from decomposed organic matter to C4 plants.  Conversely, C3 pastures have a very high demand for nitrogen to reach their full yield potential. Recycled nitrogen availability is low as a result of cool spring temperatures that limit soil microbial activity. Consequently, C3 pastures must be fertilized regularly to achieve satisfactory yields of C3 grasses.

Figure 2.1. Yield distribution of cool-season and warm-season grasses (adapted from Waller et al., 1985).

Energy Reserves  Plants synthesize CHO needed for growth and maintenance via photosynthesis.  The most active consumption of energy is during the early part of the growing season when the plant must maintain itself and continue growing during spring green-up or following defoliation (Figure 2.2).  As the plant grows more leaf material is available to facilitate photosynthesis.

Once a large portion of the potential leaf material is available for photosynthesis, more energy may be produced than the plant needs. When this happens, excess energy is stored by the plant in stem bases, roots, rhizomes, and/or stolons.

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 Perennial plants must store energy to survive the winter and begin growth the following spring. When a plant begins growth in the spring, no leaf material is available for the plant to produce energy through photosynthesis. Therefore, energy for the initial spring green-up must be provided by energy reserves stored by the plant the previous growing season. Once some leaf material is present, photosynthesis can occur and energy is produced for the plant to utilize.  If an adequate amount of leaf material remains after defoliation, the plant can grow back without utilizing stored energy reserves. However, if the plant is severely defoliated (most or all leaf material is removed) photosynthesis cannot occur and stored energy reserves must be used to fuel new growth.  The time during the growing season in which plants are grazed also affects the amount of energy reserve that will be available for regrowth (Figure 2.2).

Figure 2.2. Energy reserves at each stage of growth (adapted from Undersander et al., 2002).  Early in the growing season, when growing conditions are best, plant use of energy reserves for growth following defoliation is short lived. Little time is 17

needed early in the growing season for growth of adequate green leaf material to produce enough energy for the plant, even under heavy grazing.  However, as the growing season progresses, grazing can have a much greater impact on the energy reserve cycle. Even as the plant grows more leaf material, soil moisture in most regions of South Dakota generally declines later in the growing season. The plants’ ability to recover from grazing in mid- to latesummer may be limited by low soil moisture.  As stated earlier, perennial plants must have stored energy reserves to survive the winter and to fuel new growth in the spring. The more energy reserve the plant has in the fall before winter, the more energy will be available for spring growth.  Grazing late in the fall can have serious consequences on the energy reserve cycle. Plant recovery from light grazing at this time may not require much reserve energy, especially if most of the leaf area remains intact for photosynthesis.  However, heavy grazing may cause the plant to begin to draw heavily on its energy reserves to regrow. If the grazing time occurs too close to a killing frost, the plants energy reserves may be depleted and little reserve energy remains to survive the winter and for spring growth.  Pastures should be minimally grazed 2 to 3 weeks prior to the average first frost date in a given area.  Managing the energy reserve cycle is the key to maintaining high producing stands over the long term. A plant’s energy reserve cycle can be managed by allowing adequate rest periods between grazing periods.  Repeatedly grazing plants depletes their energy reserves and reduces their regrowth potential. Through the use of controlled grazing techniques, like rotational grazing, plants can be rested to recover from grazing and restore their energy reserves. The topic of rest intervals will be covered in more detail later in this manual.

Grass Tiller Development  All grass tillers initiate growth from a growing point developing from a bud at the base of the plant (basal bud) at or just below the soil surface (Figure 2.3).  The uppermost node on the stem is the growing point. As the plant grows, leaf tissue is produced until the growing point elevates, which is referred to as the vegetative stage of growth (Figure 2.4).

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Figure 2.3. Grass plant morphology (Waller et al., 1985). ď&#x192;ź If the growing point is triggered to become reproductive and grow a seedhead, the growing point begins to elevate vertically, stem material is produced and the tiller is formed. As the plant continues to grow and mature, nodes (joints) begin to form on the stem (jointing or elongation stage of growth).

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 At the same time, rhizomes and/or stolons begin to form from buds located at the plant base. Rhizomes are horizontal stems that remain below ground. Above ground horizontal stems are called stolons.  Both rhizomes and stolons also have nodes like vertical stems where axillary buds are located. Dormant basal and axillary buds have the potential to produce a new tiller with a new growing point.

Figure 2.4. Developmental stages of grass plants (adapted from Moore et al., 1991).  The activation of these buds through removal of the parent tiller’s growing point by grazing or frost at the end of the growing season, is the basis for perennial plants to reproduce from year to year. Buds not only account for new growth during the growing season, but also must survive the winter to produce next year’s tillers.  Removal of the growing point of a jointed grass tiller causes that tiller to die immediately. However, removal of the growing point breaks the dormancy of the basal and axillary buds of that plant allowing new tillers to grow from those buds (Figure 2.5).

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 If livestock remove the growing point of a grass tiller through grazing or trampling the tiller and breaking off the growing point, new growth must come from tillers produced by the activation of basal and axillary buds.  Similarly, when the tiller is frost killed just before winter, next year’s tillers are produced as a result of the activation of these buds when the growing point was removed by frost the previous fall.

Figure 2.5. Big bluestem tillering following defoliation. Photo by Eric Mousel.  Managing these growing points on grass plants is the basis for grazing management. Early in the growing season, the growing point of grass tillers is at or close to the soil surface. Even if livestock graze off the leaves of the plant, the growing point is not subjected to removal and the plant continues to grow after grazing. However, once the growing point becomes elevated above the soil surface, livestock can remove it and new tillers must come from activated buds.  This nearly automatic regeneration of perennial grasses appears to be a good scenario because grasses can constantly be kept at a lush, vegetative stage for livestock grazing throughout the growing season. However, a bud that is developing into a new tiller has no leaves and must depend entirely on energy produced from leaf material on remaining tillers or energy reserves stored by the plant.

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 Under heavy grazing situations, where little or no residual leaf material is present, the only source of energy to the new tiller is energy reserves. If grazing is not severe and some residual leaf material remains, most of the energy for new tiller growth will be produced by the plant and little depletion of energy reserves will occur.  If heavy grazing of the plant occurs, energy reserves will be depleted very quickly and little stored energy will be available for winter survival, growth of new buds, and initiation next year’s tillers. Growth of new tillers from buds following the removal of the growing point is very energetically expensive to the plant.  Different species elongate their stems and subsequently expose their growing points to grazing at different times during the growing season. Some species such as Kentucky bluegrass, blue grama, and sideoats grama do not elevate their growing points until just before the tiller is ready to produce a seed head. These species maintain their growing point at or below the soil surface throughout most of the growing season and are generally resistant to heavy grazing.  Grasses such as smooth bromegrass, big bluestem, and green needlegrass elevate their growing point very early in the growing season as the stem begins to elongate. This makes removal of the growing point very easy for livestock at any point of the growing season.  It is important to remember that grass species that elevate their growing points early in the growing season must be managed differently than grass species that elevate their growing points late in the growing season. Different management strategies should be used for these different species to avoid repeated removal of the growing point by livestock and the subsequent depletion of energy reserves.

References Moore, K., L. Moser, S. Waller, and K. Vogel. 1991. Staging perennial forage grasses.

Crop Production News. University of Nebraska Cooperative Extension Service.

Lincoln, NE. 11:13.

Undersander, D., B. Albert, D. Cosgrove, D. Johnson, and P. Peterson. 2002. Pastures for profit: A guide to rotational grazing. University of Wisconsin Cooperative Extension Service. Madison, WI. A3529.

Waller, S.S., L.E. Moser, and P.E. Reece. 1985. Understanding grass growth: The key to profitable livestock production. Trabon Printing Co. Kansas City, MO.

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Chapter 3 Forage Quality Forage quality is defined as the ability of a pasture or harvested forage to produce a desired livestock response through providing adequate animal nutrition (Ball et al., 2001). Providing livestock with adequate nutrition is essential to support weight gain, milk production for lactation, and efficient reproduction. Specific levels of forage quality are required for different classes of livestock, seasons, and conditions. Forage quality varies greatly among and within forage types and pasture conditions. Therefore, understanding the factors that affect forage quality is critical to successfully managing pastures and rangeland to optimize the harvest of forage yield and forage quality with grazing animals.

Components of forage quality  Plants are composed of cells, which include the contents within the cells and the cell wall. The contents within the cells, or cell solubles, are considered to be 100% digestible by the ruminant animal and the digestibility of cell solubles does not change as the plant grows and matures. However, the chemical makeup of the cell walls does change as the plant grows and matures.  Cellulose, hemicellulose, and lignin, collectively called fiber, are added to the cell wall, especially in the stem of the plant, to increase the structural integrity (Figure 3.1).  Ruminant livestock are able to partially digest cellulose and hemicellulose through the ruminal fermentation process; however, lignin is totally indigestible to ruminants.  The relative fiber content of forages will have an impact on how livestock utilize these forages. Fiber content greatly influences palatability, digestibility, nutrient content, and intake of forages consumed by livestock. Therefore, as the fiber content of forages increases, the ability of the animal to consume and digest forages can change dramatically. 

Palatability – Palatability refers to the relative likelihood that an animal will select a particular forage to eat. Generally, animals select one forage over another based on smell, feel, and taste. Palatability is influenced by the texture of plant material, leafiness, fouling by manure, and compounds within the plant that affect the taste.

Forages with a low fiber content generally are more palatable to grazing livestock than forages with a high fiber content.

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Digestibility – Digestibility is the extent to which forage is digested and absorbed as it passes through an animals digestive tract. Digestibility of a forage is inversely related to the fiber content of that forage. As fiber content increases, the ability of the

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ruminant animal to extract nutrients from that forage decreases. Ruminant livestock may be able to digest 80 to 90% of immature, leafy plant material. However, less than 50% of mature, stemmy plant material may be digested by the rumen microbial population. The digestibility of forage also has an impact on the amount of forage an animal can eat. 

Nutrient content – Nutrient content of forage refers to the level of crude protein, energy, vitamins and minerals contained within plant material. These nutrients are needed by the animal to maintain normal bodily functions and to support growth, reproduction, and lactation. In general, the nutrient content of plant material, especially crude protein, declines as the plant matures and grows.

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Intake - Intake is the level of consumption of forages by grazing livestock. Animals must consume adequate quantities of forage each day to maintain proper rumen and body functions. However, the amount of forage an animal can consume daily is affected by the fiber content of the diet. Forages with low fiber content can be readily eaten and digested by the ruminant animal. However, the rumen microbial population must break down fibrous forages through the fermentation process.. The more fiber forage contains, the longer that forage must remain in the rumen to ferment and break down. Therefore, as the amount of fiber in forage increases, the amount of that forage an animal can consume will decrease because the rumen will become full and will not hold anymore forage until it has passed through the fermentation process. Animals typically lose weight on low quality (high fiber) diets because intake is limited and the animal cannot physically eat enough of the forage to meet its nutritional requirements.

Figure 3.1. Plant cell, with fiber and soluble portions of the cell.

Factors that affect forage quality  There are many factors that influence forage quality. On rangeland and pasture, the most important factors are forage type and species, stage of plant maturity at harvest, and plant parts.

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Forage type and species  Forage quality can vary greatly between types of forages, like grasses and legumes (Table 3.1). Legumes generally produce a smaller, less fibrous stem than most grass species. The lower fiber and higher nutrient content of legumes makes them an attractive forage type to grow with grasses in improved pastures.  There also is considerable variation in forage quality among the different grasses on rangeland and upland pasture. This is because of different growth habits and photosynthetic pathways. Growth habit refers to a plants tendency to grow upright or close to the ground.  Plants that grow upright such as, big bluestem, switchgrass, western wheatgrass, and smooth bromegrass produce more fibrous tissues to increase the structural integrity of the plant. As the plant grows taller, more fiber is produced by the plant and forage quality decreases.  Plants that remain close to the ground do not need to produce as much structural fiber during their growth cycle. Plants that grow close to the ground include buffalograss, orchardgrass, blue grama, and Kentucky bluegrass.  Photosynthetic pathway also influences forage quality among grass species. Coolseason grasses and legumes such as alfalfa, red clover, orchardgrass and smooth bromegrass generally have higher nutrient content and less fiber than warmseason grasses.  Warm-season grasses like indiangrass, blue grama, prairie sandreed, and big bluestem however, have a different leaf anatomy (tissue structure) than coolseason grasses.  Although warm-season grasses photosynthesize more efficiently than cool-season grasses, their leaves contain a higher proportion of fiber and indigestible lignin.

Therefore, the digestibility of warm-season grasses is generally lower than digestibility of cool-season grasses. Crude protein content of warm-season grasses also is lower than cool-season grasses throughout their respective growth cycles.

Stage of maturity  Stage of maturity at harvest is the most important factor in managing forage quality of a forage species. In general, forage quality declines as plants grow and mature because fiber is produced within the plant to improve its structural integrity (Figure 3.2).  Grasses often are 70 to 80% digestible by grazing livestock early in the growing season. However, as plants mature and fiber content increases, digestibility can decrease by as much as 5% per week until the plant is fully mature where digestibility will level off between 40 to 50%.

25

Table 3.1. Proximate analysis and general nutrient content (dry matter basis) of selected forages (NRC, 1982). % CP

% Crude Fiber

% Cellulose

% Hemicellulose

% NDF

% ADF

15.2

28

--

22.8

35.2

58

17.4 16.6

25.2 27.4

---

26 33

29 32

55 65

25.1 12.8 17 4.1 8.1 11.3 9.7

25.2 32 24.4 -25.1 25.2 30.2

17.8 25.6 21.6 36.3 ----

32.2 ----11 --

22.8 30.7 28.3 43.2 30 30 37.6

55 ---41 41 --

12.2 9.1 13.9

32.1 33.5 29.7

-33.9 --

22.1 30.6 --

32.9 36.4 35.6

55 67 --

Legumes Alfalfa Red clover Sweetclover Trefoil

20.5 14.6 15.4 20.6

23 26.1 32.6 21.2

34.6 ----

9.9 8 ---

32.1 35 ---

42 43 ---

Cereal grains Oats Rye Triticale Wheat

9.5 12.1 16.5 27.4

32 34.6 33 17.4

---23.9

23.6 22.1 -23.6

38.4 38.9 -28.4

62 61 -52

13.6 5.8

24.9 34.2

30.9 --

---

---

---

13.1 6.5 10.2

27.2 32.7 27.7

----

----

--11.1

----

8 6.4 3.1 9.2 8.9

22.6 34.4 35.8 11.1 31.6

------

-28 45 ---

-39 44 14 --

-67 89 ---

16.8 8.8

30.9 36.1

---

26 25

29 40

55 65

14.1 5.1

23.5 36.7

---

---

---

---

Species Cool-season grasses Smooth bromegrass Kentucky bluegrass Early vegetative Elongation Orchardgrass Early vegetative Elongation Reed canarygrass Needlegrass Redtop bent Perennial ryegrass Sedges Timothy Early vegetative Elongation Crested wheatgrass

Warm-season grasses Big bluestem Early vegetative Mature Blue grama Early vegetative Mature Buffalograss Corn (Maize) Mature with ears Mature, no ears Cobs Ears with husks Inland saltgrass Sudangrass Early vegetative Mature Switchgrass Early vegetative Mature

Plant parts ď&#x192;ź Leaves contain more protein and less fiber than stems in both grasses and legumes. The disparity between quality of these different plant parts is often 26

measured as leaf to stem ratio, or the amount of leaf material (by weight) divided by the amount of stem material (by weight). Leaf to stem ratios vary widely among forage species and decrease as a whole as grasses mature.  Early in the season, a forage species such as big bluestem may have a leaf to stem ratio near 4:1 (4 parts leaf to 1 part stem by weight) (Figure 2.3). By mid-season, the leaf to stem ratio may decrease to 2:1, and when the plant is reproductive and puts out a seedhead, the leaf stem ratio may decrease further to 0.5:1 (Figure 3.4).  A forage species like orchardgrass; however, has less dramatic shifts in leaf to stem ratio as the plant matures. In the spring, orchardgrass may have a leaf to stem ratio of 3.5:1, at mid-season, leaf stem ratio may be 2.5:1, and 1.5:1 at maturity.  Leaf to stem ratio is very closely related to forage quality of a grass or legume.

Leaves are higher in quality than stems, and the proportion of leaf material on a forage plant decreases as the plant matures.

Figure 3.2. Relationship between stage of plant maturity and forage quality (Adapted from Undersander et al., 2002).

27

Forage quality testing  As described above, nutrient content of forages can vary considerably. Although using standard book values (Table 3.1) or estimating the forage quality of forages during the grazing season can help make some management decisions, inaccurate estimates of nutrient contents of forages can lead to over- or underfeeding certain nutrients resulting in wasted money or inadequate livestock nutrition.  Evaluating forage quality using chemical analysis is an accurate and relatively quick method of determining nutrient content of forages. Chemical testing will help managers effectively match livestock requirements to available forages and nutrient supplementation programs.

Figure 3.3. Steer grazing big bluestem with a high leaf to stem ratio. Photo by Alexander Smart.

Forage analysis  Results of a chemical forage analysis are expressed on both an “as received” or “as fed” and on a 100% dry matter (DM) basis. The as-fed basis includes the moisture contained with in the forage when it was samples from the pasture (Figure 3.5).  Dry matter is the percentage of the feed that is not water. Therefore, dry matter basis means all of the moisture in the forage samples was removed before the analysis was performed. Nutrient content values are always larger when reported on a dry matter basis than when reported on an as-fed basis (Anderson et al.

1994).

28

%DM = 100 â&#x20AC;&#x201C; (% moisture) To convert from an as-fed to a dry matter basis: DM basis = Nutrient (as-fed) (% DM/100)

Figure 3.4. Steer grazing big bluestem with a low leaf to stem ratio. Photo by Alexander Smart.

Crude Protein. Crude protein (CP) is not a direct measurement of protein but a measurement of total nitrogen contained within the forage sample. Crude protein provides no information about amino acid composition, availability of protein, the amount digested in the rumen (DIP), or the amount that escapes rumen fermentation (UIP). However, crude protein does give a good indication of a forages ability to meet certain livestock requirements.

CP = % Nitrogen x 6.25 Neutral Detergent Fiber. Neutral detergent fiber (NDF) is a component of a chemical procedure in which a forage sample is placed in a weak acid that dissolves away all of the cell contents contained in the sample. The amount of sample that remains after the weakacid treatment is the amount of cellulose, hemicellulose, and lignin or fiber content of the forage. As such, NDF is a good predictor of feed intake. Higher quality samples have lower NDF values and intake is generally high. As plants mature, the NDF of forage will increase, indicating that forage quality is lower and intake will be reduced.

Acid Detergent Fiber. Acid detergent fiber (ADF) is a secondary chemical test that uses a stronger acid to dissolve the hemicellulose in a forage sample. An ADF test tells us how 29

Figure 3.5. Example forage analysis. much cellulose and lignin is contained in the sample. ADF is a good indicator of the digestibility of a forage. The lower the ADF the more energy the forage contains and the more digestible it will be to grazing livestock.

30

Minerals. Calcium (Ca), phosphorous (P), magnesium (Mg), and potassium (K) values are expressed as a percentage of each sample.

Digestible Dry Matter. Digestible dry matter (DDM) is an estimate of the digestibility of a forage. DDM is calculated from ADF values. As ADF of forage increases, DDM decreases. %DDM = 88.9 – (0.779 X %ADF) Dry Matter Intake. Dry matter intake refers to the amount of a forage an animal will consume is dependent on the quality of that forage. Calculating DMI from NDF can estimate the intake of forage as a percent of the body weight of that animal.

DMI (% of body weight) = 120 / %NDF Relative Feed Value. Relative feed value (RFV) is an index to rank alfalfa, grass hay, haylage, and silage based on the DDM and predicted DMI of the sample. The value derived from RFV calculations is useful only as an index value to compare against the RFV of other samples. It is of no use in developing or evaluating diets.

RFV = DDM x DMI 1.29  Visual appraisals, estimates, and book values are generally inadequate to make good management decisions. Using chemical analyses of forages can provide maximum animal performance at the lowest cost for a reasonable expense.

Sampling pasture forages  Sampling forages in a pasture can be a challenge because the maturity of forage plants is constantly changing. Sampling forages in a pasture should be done every 2 to 3 weeks so adjustments for changing animal requirements and to rotation speed through pastures can be made if necessary.  In rotationally grazed pastures, collect several random samples in each pasture that will grazed in a 2 or 3 week period. Try to make samples representative of what livestock are consuming, avoiding weeds and other species livestock will not eat.  For a continuously, season-long grazed pasture, forage samples should be collected from several areas within the pasture. The larger the pasture, the more samples will be required to get an accurate test for the pasture. Generally, 20 samples per 80 acres should be adequate.  When taking samples, be sure to sample areas where livestock have been grazing.

If a portion of your sample contains old growth from the previous year, it should be included along with current year’s growth.

31

ď&#x192;ź Place the samples in several paper or mesh bags to allow the plant material to begin drying. Ideally, samples should be taken to the lab as soon as possible. If not mailed to the lab immediately, place the samples in an area where the sample will quickly air dry. Do not let the samples mold or the chemical analysis will be compromised.

References Anderson, B., R. Rasby, T. Mader, and R. Grant. 1994. Testing livestock feeds for beef cattle, dairy cattle, sheep, and horses. University of Nebraska Cooperative Extension Service. Lincoln, NE. G89-915-A. Ball, D.M., M. Collins, G.D. Lacefield, N.P. Martin, D.A. Mertens, K.E. Olson, D.H. Putnam, D.J. Undersander, and M.W. Wolf. 2001. Understanding forage quality.

American Farm Bureau Federation Publication 1-01, Park Ridge, IL. Baron, V.S., Alistair C. Dick and Jane R. King. 2000. Leaf and Stem Mass Characteristics of Cool-Season Grasses Grown in the Canadian Parkland. Agron J. 92:54-63.

Mousel, E.M. 2001. Summer grazing strategies following early season grazing of big bluestem. M.S. Thesis. University of Nebraska â&#x20AC;&#x201C; Lincoln. Lincoln, NE. National Research Council (NRC). 1982. United States-Canadian tables of feed composition. Washington, DC. National Academy Press.

Undersander, D., B. Albert, D. Cosgrove, D. Johnson, and P. Peterson. 2002. Pastures for profit: A guide to rotational grazing. University of Wisconsin Cooperative Extension Service. Madison, WI. A3529.

32

Chapter 4 Forage Distribution and Stocking Rates for South Dakota Rangelands Rangeland forage species  Unlike improved pastures, native rangelands contain a variety of different coolseason and warm-season forage species together on the same site. Having both cool- and warm-season grass in the same pasture can provide some unique management challenges. Understanding the forage distribution of different forage species throughout the growing season is key to properly managing rangelands in South Dakota.  Western wheatgrass and green needlegrass are the two primary cool-season forage species on rangeland. While prairie sandreed, little bluestem, blue grama, buffalograss, sideoats grama, and tall dropseed compose the warm-season grass component.  Many other species may be present on any given rangeland site, but these species account for the majority of the annual forage production and therefore are referred to as key forage species. Grazing management plans should be centered on the production distribution of these key forage species.

Using proper stocking rates on rangeland  The state is divided into six climate zones to adjust for precipitation differences across the state that influence vegetation type and production (Figure 4.1). As a result of precipitation differences across the state, native rangelands differ in their ability to produce specific kinds, proportions, or amounts of vegetation.  Figure 4.2 shows the initial recommended stocking rates for rangeland and pastures across the state when they are in optimum range condition. However, rangelands in South Dakota tend to deviate from optimal condition due to past grazing effects, drought, destructive weather events, etc. Therefore, the initial recommended stocking rates may need to be adjusted for annual precipitation fluctuations and range condition of the site in question.  Stocking rates in Figure 4.2 are given in acres/cow/month. To calculate the stocking rate for the entire grazing season, take the stocking rate provided for you in Figure 4.2 and multiply it by the number of months you intend to graze over the whole grazing season.

33

Figure 4.1. Climate zones for South Dakota (Schumacher and Johnson, 1994).  Example: If you are in northern Meade County, you will find that your suggested initial stocking rate is 5.25 acres/cow/month. If your grazing season is anticipated to last 6 months over the summer, simply multiply the following: 5.25 acres/cow/month x 6 months = 31.5 acres/cow for the 6 month grazing season Improved pastures Improved pasture forage species  Different forage species have different uses within a forage-livestock system.

Each forage type has its own advantages and disadvantages based on: 1) its seasonal forage distribution, 2) its adaptability to environmental and site conditions in which it is expected to produce forage for livestock, and 3) its utility in complementary forage systems.  Each forage species has a distinct seasonal growth pattern (Figure 4.3). Coolseason grasses such as smooth bromegrass or crested wheatgrass prefer the cooler temperatures of the spring (mid-April to June) and fall (early-September to midOctober) months of the growing season. They are most productive in the spring but often go dormant through the hot summer months. Limited regrowth in the fall can be expected from most cool-season grass species.  Legumes are also cool-season species, but generally begin growth a little later in the spring than cool-season grasses. However, unlike cool-season grass, legume 34

Figure 4.2. Suggested stocking rates (acres/cow/month; assuming average cow weight of 1400 lb cow) across South Dakota. (adapted from Albec et al., 1948).

35

 forage distribution through the growing season generally is much more uniform because many legume species tolerate heat and drought better than cool-season grasses.  Warm-season grasses grow best in the summer heat (mid-May through September) that causes most cool-season species to go dormant. Although forage quality of warm-season grasses is typically lower than that of cool-season species, they provide an excellent source of forage for grazing livestock. Warm-season grasses generally are more efficient in their use of available soil moisture making them relatively drought tolerant.  Alternative forages such as winter wheat, oats, rye, and triticale can provide excellent forage for livestock in the early spring when cool-season forages are just getting started on their spring green-up. Cover crops and crop residues like corn stalks, can also provide excellent grazing in the late fall after pastures have mostly been utilized and are being rested before the first frost.  Knowledge of the characteristics of forage species and how adaptable they are to the environmental and site conditions they will be expected to grow in is essential to selecting the appropriate introduced species for your forage-livestock system.

Considering factors such as regrowth potential and compatibility with other forage types also can help determine which forage species will best fit your production goals.  Complementary forages systems match the seasonal forage distribution of different forage species. Alternative forages such as annual cereal grains or crop residues fit nicely into complementary forage systems. Sequentially grazing different forage types during their peak production time improves both animal performance and improves grass pasture sustainability by distributing animal demand for forage across several different forage types throughout the grazing season.  Different grass and legume species have different growth characteristics, yields, and uses that will determine their utility in a forage program. Understanding these characteristics and matching different forages types to site conditions and production goals of the livestock operation will provide the most productive and sustainable forage scenarios.

Cool-season grasses Smooth bromegrass – is a highly recommended forage species for improved pastures in eastern and east central South Dakota. It has high yield potential, excellent forage quality, and is relatively compatible with legumes. Regrowth following haying or intensive grazing is limited for smooth bromegrass and, therefore, it should be used as part of a complementary forage system rather than grown as a sole source of forage.

36

Figure 4.3. Seasonal forage distribution of selected forage species for improved pastures in South Dakota (adapted from Waller et al., 1985).

Kentucky bluegrass â&#x20AC;&#x201C; is generally considered an invader of pastures and rangeland in South Dakota. It is rarely seeded as a source of forage, but is prevalent in most areas.

This species can easily establish itself on infertile, overgrazed pastures in the eastern, central and west central regions of the state. May be useful in some situations where intensive use is common as it is relatively resistant to heavy grazing, requires little maintenance, and produces relatively high quality forage.

Intermediate wheatgrass â&#x20AC;&#x201C; is much more drought tolerant than smooth bromegrass. It provides excellent quality forage until maturity when it becomes stemmy and brittle. It 37

does not grow or regrow well in hot, dry weather. Intermediate wheatgrass is not a strong competitor with other cool-season grasses or aggressive legumes and therefore should be seeded as a monoculture.

Crested wheatgrass – is extremely drought tolerant and will grow on most any soil type or texture. Well-suited to dry, clayey soils, crested wheatgrass is often found seeded in the far west and northwest pastures of the state. It greens up earlier than most other coolseason grasses often ready to graze by mid-April.

Orchardgrass – is generally higher yielding forage species than smooth bromegrass and readily regrows following grazing. Orchardgrass is an extremely competitive species that is much more legume-compatible than either smooth bromegrass or timothy. Because of its aggressive nature, if a legume – orchardgrass mixture is desired, a competitive legume such as red clover should be grown with it.

Quackgrass – Although quackgrass has become such a serious weed problem on cultivated fields in eastern South Dakota, it is often overlooked as a source of forage.

Quackgrass is part of the wheatgrass family and provides excellent yields and good quality forage in the early and late months of the grazing season.

Reed canarygrass – is nearly the only forage option available on sites that are routinely flooded or where the water table traditionally lies close to the soil surface, well within the rooting zone of most grass species. Although reed canarygrass is extremely difficult to establish, it generally persists very well, even under intensive grazing. However, reed canarygrass is an extremely aggressive species and may invade and displace other plant communities where excessive soil moisture is available.

Timothy – is an excellent forage species for pastures in the far eastern part of the state.

Timothy produces excellent yields, good forage quality, and is very compatible with less aggressive legumes. Timothy does not tolerate heat or drought and generally will not persist well outside of the far eastern counties in South Dakota.

Warm-season grasses Big bluestem, Little bluestem, Indiangrass, and Switchgrass – are native warm-season tallgrasses that grow well on most sites east of the Missouri River. These warm-season species provide excellent forage in the heat of the summer months when most coolseason species have gone dormant. Switchgrass is relatively easy to establish in welldrained soils where plenty of soil moisture is present, but matures very early in the summer, reducing forage quality. Big bluestem, little bluestem, and indiangrass generally are difficult to establish, are poor competitors with invading weeds, and can be difficult to manage in intensive grazing systems. However, these grasses are persistent and vigorous once established and will tolerate grazing if properly managed.

Forage legumes

38

Alfalfa â&#x20AC;&#x201C; is an extremely high yielding legume that provides excellent summer regrowth because of its strong persistence and good drought tolerance. Alfalfa does not typically tolerate flooding or overgrazing, and ruminal bloat can be a challenge if stand density of alfalfa in pastures is too high. Mixing legumes 50:50 with grass species or using bloat prevention devices such as proloxalene or ionophores will reduce the incidence of bloat considerably.

Table 4.1. Characteristics of selected cool-season, warm-season, and legume species for improved pastures (Undersander et al., 2002).

Species Cool-season grasses Smooth bromegrass Kentucky bluegrass Intermediate wheatgrass Crested wheatgrass Orchardgrass Perennial ryegrass Quackgrass Reed canarygrass Creeping foxtail Timothy Warm-season grasses Big bluestem Indiangrass Switchgrass Sudangrass

Legumes Alfalfa Birdsfoot trefoil Red clover Kura clover White clover

Regrowth potential

Legume compatibility

Winter hardiness

Ease of establishment

Drought tolerance

Flooding tolerance

Species persistence

fair

good

excellent

fair

good

fair

good

good

poor

excellent

good

fair

fair

good

fair

poor

excellent

good

good

fair

good

poor excellent excellent excellent good good fair

poor good fair good poor poor good

excellent good poor excellent excellent excellent excellent

excellent good excellent n/a poor good good

excellent fair fair good good poor poor

fair fair fair fair excellent excellent poor

excellent good poor excellent excellent excellent poor

good good good good

poor poor poor poor

good good good n/a

fair fair fair excellent

excellent excellent excellent excellent

fair good fair fair

good excellent good n/a

Regrowth potential

Bloat potential

Winter hardiness

Ease of establishment

Drought tolerance

Flooding tolerance

Species persistence

good fair fair excellent good

high none high high high

excellent excellent fair excellent excellent

good poor excellent poor excellent

good poor poor good good

poor fair fair fair fair

good excellent fair excellent excellent

Birdsfoot trefoil â&#x20AC;&#x201C; is a native legume that does not cause bloat in livestock. Birdsfoot trefoil maintains its quality better than any other legume or grass but is low yielding and relatively difficult to establish. It is a great choice for sites with poor soil fertility and it is 39

extremely persistent but it can be overgrazed if not properly managed and does not tolerate drought well.

Red clover – is very aggressive and is a great choice to include in pastures with an aggressive grass species. It is very high yielding and is extremely easy to establish, but does cause ruminal bloat and generally only persists in stands for 3 to 5 years.

Kura clover – is an extremely persistent legume that produces very high quality forage, but does cause ruminal bloat. It spreads readily through rhizomes, which makes it a very aggressive species once established and should be mixed with an aggressive grass species such as orchardgrass to avoid stand domination by kura clover.

White clover – is an excellent choice for pastures that are traditionally high traffic areas and commonly are overgrazed. White clover is easy to establish and very persistent, but is very low yielding and can cause ruminal bloat. White clover does not compete well with tall or aggressive grass species and therefore should not be seeded into high producing pastures.

Using proper stocking rates on improved pastures and alternative forages  Using proper stocking rates on improved pastures is a key component of good grazing management. Applying excessive stocking rates to pastures during the growing season results in overuse of key forage species causing depletion of energy reserves and slow root growth. Weakening key forage species will open up the forage stand for invasion by undesirable species and will reduce the amount of usable forage in your pastures. Increased soil erosion, poor winter survivability, and increased input costs (e.g., fertilizer and herbicides) also will result from improper management of improved pastures.  On the other hand, undergrazing pastures can also lead to production problems.

Most improved pasture forage species are fast growing, high yielding species.

When these pastures are understocked, forage production quickly outpaces livestock consumption, resulting in low utilization of forage by livestock, poor quality forage, and lower animal performance.  Proper stocking rates for improved pastures, legume-grass pasture and alternative forage species are listed in Tables 4.2, 4.3, and 4.4. Using proper stocking rates on pastures will ensure maximum forage production and optimum animal performance over the long-term.  Similar to the stocking rates provided for rangelands, the stocking rates for improved pastures, legume-grass pasture and alternative forage species shown in Tables 4.2, 4.3, and 4.4 are given in acres/cow/month. To calculate the stocking rate for the entire grazing season, take the stocking rate provided for you in the table and multiply it by the number of months you intend to graze over the whole grazing season.

40

ď&#x192;ź Example: If you are in northern Hand County, you will find that your suggested initial stocking rate on smooth bromegrass pasture is 0.92 acres/cow/month. If your grazing season is anticipated to last 6 months over the summer, simply multiply the following: 0.92 acres/cow/month x 6 months = 5.5 acres/cow for the 6 month grazing season Table 4.2. Suggested initial stocking rates (acres/cow/month; assuming average cow weight of 1400 lb cow) for improved pastures containing the listed species for each climate zone in South Dakota.

Climate Zone East West central central

Species Smooth bromegrass Intermediate wheatgrass Crested wheatgrass Orchardgrass Quackgrass Reed canarygrass Timothy Warm-season tallgrasses (i.e. big bluestem, indiangrass)

Wester Eastern n --------------acres/cow/month-------------0.625

0.92

1.33

2.0

0.67

1.0

1.38

1.79

0.79 0.71

1.29 -

1.54 -

1.92 -

0.34 0.89

0.43 -

-

-

0.62

0.79

1.04

1.57

Table 4.3. Suggested stocking rates (acres/cow/month; assuming average cow weight of 1400 lb cow) for selected legume forage species in each climate zone in South Dakota.

Eastern

Climate Zone East West central central

Western

Species

Alfalfa - grass mix

Legume/cool-season grass mix (50:50) ------------------acres/cow/month-------------------0.64 0.83 -

Red clover - grass mix

0.66

0.95

-

-

Birdsfoot trefoil - grass

0.58

-

-

-

41

Table 4.4. Suggested stocking rates (acres/cow/month; assuming average cow weight of 1400 lb cow) for selected alternative forage species in each climate zone in South Dakota.

Eastern Species

Climate Zone East West central central

Western

Soil type

Winter wheat Oats Rye Triticale Millet

Cereal annuals -------------------acres/cow/month------------------.7 1.0 1.5 2.6 0.7-0.93 1.0 1.5 2.6 0.56 0.56 0.93 1.0 0.56 0.7 1.5 2.0 0.26 0.31 0.39 0.78

Cornstalks Sorghum Wheat Turnips

Crop residues (not including supplements) -------------------acres/cow/month------------------0.56 0.7 0.93 0.7 0.93 0.93 1.0 1.0 1.0 1.0 1.0 0.47 0.7 1.0 -

Calculating stocking rates from forage production In order to effectively correct your stocking rate for the specific area you live in, it may be useful for you to have the tools needed to calculate your stocking rate from forage production data you have collected in your own pastures. ď&#x192;ź Form a 41.5 inch piece of cable into a hoop by crimping the ends together with a copper cable crimp. When done, the hoop should measure 13 5/8 inches in diameter. ď&#x192;ź Lay your hoop down in the area to be sampled from and, using grass shears, clip all vegetation down to ground level as shown in Figures 4.4 and 4.5. Discard all

42

forb and shrub species as cattle generally don’t eat a tremendous amount of these species.  Collect about 20 samples for every 80 acres in your grazing unit.  Put all of the clipped material into a brown paper bag.  When you have collected all of your samples, weigh them using a metric scale.

Subtract the weight of the bag from the total weight. The conversion to pounds/acre only works if the samples are measured in grams. Therefore, if samples are weighed in ounces, the weight should be converted to grams.

Figure 4.4. Sampling forage production using the hoop clipping method.

Figure 4.5. Clipping vegetation at ground level is essential to get a good sample.  To convert ounces to grams, multiply by 28.34 grams per ounce.

Example: 1.5 ounces x 28.34 grams per ounce = 42.51 grams

43

 The conversion from grams to pounds per acre using this hoop is 100.

Example: 27 grams x 100 = 2700 lb/acre of forage.  Now correct for moisture by multiplying by 0.85.

Example: 2700 x 0.85 = 2295 lb dry matter forage/acre  Based on the “take-half/leave-half” philosophy of grazing management, only about 25% of the total amount of available forage is going to be consumed by livestock (leave 50% for the health of the plant, and 25% will be lost to wastage, insects, etc.)  Now correct the total sample weight for the amount that will be consumed by livestock.

Example: 2295 lb/acre x 0.25 (percent) = 573.75 lb/acre consumed  Now divide by 780 lb to convert the amount consumed into an index value.

Example:

573.75 lb/acre consumed 780 lb consumed/cow/month

= 0.73

 To convert the index value to acres/cow/month by dividing by the index value.

Example:

1 / 0.73 = 1.36 acres/cow/month

 To calculate the season-long stocking rate, multiply the acres/cow/month by the number of months in the grazing season.

Example: 1.36 acres/cow/month x 6 months = 8.16 acres/cow for the grazing season Predicting forage production in eastern South Dakota The ability of grazing managers to predict forage production prior to the grazing season is a extremely. Access to this type of data allows managers to make informed decisions regarding stocking rates and livestock management prior to the start of the grazing season.  The use of tools that can predict annual forage production allows managers the opportunity to make critical management decisions before the grazing season starts. Research at SDSU has shown that annual forage production in the eastern half of South Dakota can be accurately predicted based on the amount of liquid precipitation received in April.

44

 Figure 4.6 illustrates the relationship between annual forage production in eastern South Dakota and the amount liquid precipitation received during the month of April.  Unfortunately, this relationship does not hold up for western South Dakota rangeland. The amount of annual forage production in the west is determined by more variables than just precipitation in April. Therefore, this tool will not be of much use to managers in the west.

Forage Biomass (lb/acre)

 By using this tool, managers will effectively predict how much forage production will be available to graze by the end of April by simply recording the amount of precipitation their ranch received during the month. If a ranch received 2.5 inches of precipitation in April, they can expect about 2,500 pounds per acre of forage.

4500 4000 3500 3000 2500

R-square = 0.77 Y = 1208 + 530 x April precipitation

2000 1500 1000 500 0 0

1

2

3

4

5

April Precipitation (inches)

Figure 4.6 Relationship between average forage biomass and April precipitation in eastern South Dakota (Smart and Mousel, 2006).  Convert pounds/acre to a stocking rate using the formula from above.

Example:

2,500 lb/acre x 0.25 780 lb consumed/cow/month = 0.80

Convert to acres/cow/month: 1 / 0.80 = 1.25 acres/cow/month Convert to season-long stocking rate by multiplying monthly stocking rate by the number of months you plan to graze: 1.25 acres/cow/month x 6 months = 7.5 acres/cow for the grazing season 45

References Albec, L.R., E.W. Klosterman, W.H. Burkitt, and H.R. Olson. 1948. South Dakota grasslands their condition and management. South Dakota State University Ag. Exp. Sta. Bull. Circular 70.

Schumacher, C.M. and J.R. Johnson. 1994. South Dakota range site. South Dakota State University Cooperative Extension Service. EC736.

Smart, A.J. and E.M. Mousel. 2006. Predicting Forage Production, Stocking Rate, and Beef Production in Eastern South Dakota: A Case Study. South Dakota State University. Department of Animal and Range Sciences. Beef Report.

Undersander, D., B. Albert, D. Cosgrove, D. Johnson, and P. Peterson. 2002. Pastures for profit: A guide to rotational grazing. University of Wisconsin Cooperative Extension Service. Madison, WI. A3529.

Waller, S.S., L.E. Moser, and P.E. Reece. 1985. Understanding grass growth: The key to profitable livestock production. Trabon Printing Co. Kansas City, MO.

46

Chapter 5 Animal Nutrient Requirements Balancing forage quality and quantity with nutrient requirements of livestock is essential for successful forage-livestock production programs. In the last chapter the importance of stocking rates to maintain sustainable, long-term pasture performance was discussed. However, forage produce in pastures is used most efficiently when it is balanced by an equal demand by livestock for forage. In this chapter we will discuss how animal demand must match forage supply to optimize both forage utilization and animal performance.

Animal nutrient requirements Forage dry matter intake  Dry matter intake of forage is generally limited by the capacity of the digestive tract and is therefore heavily influenced by the body weight of the animal.

However, forage intake is also highly correlated with forage quality. Higher quality forages are digested and passed through the ruminant digestive tract more quickly than lower quality forages resulting in higher rates of intake.  Similarly, environmental conditions such as heat stress may decrease dry matter intake while cold stress may increase dry matter intake. Daily dry matter intake can range from 1.5% to 3% of the animal’s body weight but is generally fluctuates from 2% to 2.5%.

Energy  The ruminant animal requires energy for maintenance, growth, reproduction, gestation, and lactation. The majority of the energy for grazing livestock is supplied through the process of ruminal digestion of forages. Figure 5.1 shows the net energy requirement for a 1200 lb March calving cow with peak milk production of 20 lb/day.  When adequate protein is available, the rumen is able to digest and extract energy from a variety of fibrous feedstuffs that non-ruminants cannot use. When protein deficiency in the rumen exists, rumen bacteria are unable to efficiently ferment and digest roughage, reducing the amount of energy that can be extracted.

Protein  Rumen microbes degrade a portion of the dietary protein and utilize the nitrogen and amino acids from these proteins in the synthesis of body tissues. As such, the rumen microbes themselves have a protein requirement and must be supplied

47

FEB

JAN

DEC

NOV

OCT

SEP

AUG

JUL

JUN

MAY

APR

20 18 16 14 12 10 8 6 4 2 0

MAR

NE (Mcal/day)

with adequate dietary protein to function properly in roughage digestion. Figure 5.2 illustrates the metabolizable protein requirement for a 1200 lb March calving cow with peak milk production of 20 lb/day.

Month

Figure 5.1. Net Energy (NE) requirement for a 1200 lb, March calving cow with peak milk production of 20 lb/day (NRC, 1996).  When evaluating proper nutrition for the ruminant animal, a high priority should be placed on providing adequate ruminally degradable protein to support replication of the microflora of the rumen. However, in contrast to high-grain diets, the utilization of non-protein nitrogen sources such as urea is not good in forage based diets. The crude protein system has long been the standard for evaluating dietary protein content of feedstuffs.  Crude protein is calculated by multiplying the nitrogen concentration of the feed by 6.25. The multiplier (6.25) comes from the fact that proteins contain, on average, 16% nitrogen (1/16 = 6.25). Dietary protein requirements for beef cattle and the amount of protein available in forage species are shown in Figure 5.3.

Vitamins and minerals  Vitamin and mineral nutrition is a small but critical component of any livestock diet. Although little is known about specific dietary requirements for most macro and micro minerals, the National Research Council has developed equations to determine calcium and phosphorous requirements and provides general dietary guidelines and maximum tolerable levels for the other minerals.  Most of the mineral needs of livestock can be met by the pasture alone unless livestock are grazing relatively low quality forages like corn stalks or wheat stubble. However, in many cases, one or more minerals may be deficient in the diet depending on local geological formations and soil conditions. Furthermore, 48

FEB

JAN

DEC

NOV

OCT

SEP

AUG

JUL

JUN

MAY

APR

MAR

MP, lb/day

2 1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0

Month

Figure 5.2. Metabolizable protein (MP) requirement for a 1200 lb, March calving cow with peak milk production of 20 lb/day (NRC, 1996). concentrations of many macro-minerals decrease as grass matures throughout the growing season, therefore some mineral supplementation will likely be needed. ď&#x192;ź Salt however, should always be provided free-choice. It is generally a good idea to provide trace mineralized salt to ensure mineral requirements are being met.

30

Percent (%)

25

Smooth bromegrass Green needlegrass

20

Crested wheatgrass

15

Western wheatgrass Big bluestem

10

Native range

5

Minimum cow requirement

0 MAY

JUN

JUL

AUG

SEP

OCT

NOV

Month

Figure 5.3. Seasonal distribution of crude protein (CP) content of selected grass species and minimum CP requirements of a 1200 lb. cow (Sedivek et al., 2007; NRC, 1996; Johnson et al., 1952).

49

Water  Clean water is an essential nutrient for grazing livestock.

Factors that affect animal nutrient requirements 1. Stage of production  Animal’s nutritional requirements are influenced by stage of production (Figure 5.4). The production cycle of brood herds can be divided into four stages: (1) parturition to breeding; (2) breeding to weaning; (3) mid-gestation; and (4) late gestation. Important nutritional considerations (as defined by Rasby and Rush 1996) in each of the four stages of production are as follows: Parturition to Breeding  Females are lactating during this stage of production, causing nutrient requirements to be greater than at any other stage. Females in moderate body condition need to be fed to meet their nutrient requirements and to maintain body condition during the winter to have a short interval from parturition to breeding.  Females in good body condition can lose some condition after parturition and still attain a high rebreeding percentage. If females in good condition lose weight and body condition after parturition, it is essential that turn-out on spring pasture is early so they are maintaining or gaining weight prior to the beginning of the breeding season.  Rebreeding performance for females in thin body condition can be highly variable. Poor condition (thin) females that experience little stress from calving to breeding, may efficiently rebreed. Poor condition females that experience stresses related to nutrition, weather and calving, may have lower rebreeding performance.

50

 Figure 5.4. Beef cattle nutrient requirements response to physiological stage.

Breeding to Weaning  Milk production for most lactating females will be declining during this stage of production resulting in lower nutritional requirements. Females with average or low milking ability may actually gain weight during this period if good summer pasture is available.  However, limiting nutrition during this period generally results in lighter offspring at weaning. Females bred for high milk production may lose weight during this stage and will enter mid-gestation in poor condition.

Mid-Gestation  Nutrient requirements for females generally are lowest during this stage of production because the offspring has been weaned from the female and nutrients required by the developing fetus are minimal. Females in good condition may be allowed to lose some weight during this period without severely reducing productivity.  Females in poor or moderate body condition likely will be required to gain condition or maintain body weight and body condition to avoid poor reproductive performance.

Late Gestation  The fetus is growing rapidly during this stage of production, causing the nutrient requirements of the female to increase. Females in good condition may lose some weight during this period but give birth to a strong, healthy offspring.  Females in poor condition should be fed to maintain or gain weight and body condition. Females experiencing excessive weight losses during this period likely will be slow to cycle and rebreed after parturition.

2. Age of animal After parturition, young females should be fed separately from mature females until spring pasture is available. Young, lactating females will require a higher percentage of energy and protein in their diet than mature females before and after parturition. Handling young females separately from mature females also is important as younger animals often are bullied by mature animals, often times resulting in less than adequate nutrition.

3. Cow size and condition

51

Large frame animals consume more feed than smaller frame animals; however, on a percentage basis, smaller frame animals require a higher-quality diet. Weight variation due to differences in condition does not appreciably affect the amount of feed needed for satisfactory production as long as weather is not extreme.

For example, a thin 1,000 pound cow and a fleshy 1,200 pound cow both need about the same feed as a 1,100 pound cow of the same frame size during the dry period. However, thin cows need extra energy during cold stress to maintain normal body temperature.

4. Milking ability Superior milking females require rations containing more energy, protein, calcium and phosphorus than average milking females if they are to rebreed and produce an offspring every year. Young females, regardless of milking ability, generally need to be fed to gain weight during the first three months of lactation to rebreed.

This may require feeding high energy supplemental feeds such as grain or corn silage after parturition until pasture is available. Furthermore, mature, superior milking females will require high quality forages with high energy content following parturition, or rebreeding performance may be compromised.

5. Weather On most winter days, animals fed recommended amounts of feed will produce enough heat to maintain body temperature. Cold weather stress probably does not justify feeding high energy feeds if livestock are fed a full feed of forage properly supplemented with protein. Cattle will adjust intake to compensate for cold temperatures provided they have access to roughage. When weather conditions make it impossible to get adequate feed and water to livestock for long periods of time, animal performance can be reduced. Livestock in moderate to good condition can withstand stress situations better than those in poor condition.

6. Length of breeding season Short breeding seasons require well-managed nutritional programs from 60 days before calving through breeding. To have a successful short breeding season, females must be in good body condition at parturition.

References Hammack, S.P. and R.J. Gill. 2000. Factors and Feeds for Supplementing Beef Cows.

Texas Agricultural Extension Service. Texas A&M University. L-5354. 4-00.

52

Johnson, L.E., A.L. Moxon, and R.L. Smith. 1952. Wintering Beef Cows on South Dakota Ranges. Agricultural Experiment Station. South Dakota State College.

Brookings, SD 57007. Exp. Sta. Bul. 419.

Marston, T. 1997. Nutritional requirements for beef cows. Forage Facts. Kansas Forage Task Force. Kansas State University Agricultural Experiment Station and Cooperative Extension Service. Kansas State University. Manhattan, KS. National Research Council (NRC). 1996. Nutrient Requirements of Beef Cattle. 7th ed.

Natl. Acad. Press, Washington, DC. Rasby, R. and I. Rush. 1996. Feeding The Beef Cow Herd--Part I: Factors Affecting the Cow Nutrition Program. University of Nebraska Cooperative Extension Service.

University of Nebraska. Lincoln, NE. G80-489-A. Sedivek, K.K., D. Tober, W.Duckwitz, D. Dewald, and J. Printz. 2007. Grasses for the Northern Great Plains. North Dakota State University. R-1323.

53

Chapter 6 Matching Livestock Demand to Forage Supply Forage Demand Fixed vs. Variable Stocking Rates One of the basic questions regarding stocking rates is how best to apply them in a management scenario. There are two ways to apply a stocking rate: 1) fixed season-long and 2) vary the stocking rate with forage the variation in forage production throughout the year.  With fixed stocking rates undergrazing in the first half of the season and overgrazing in the last half of the season are common.  Fixed stocking rates typically don’t match livestock demand to forage supply very well. Figure 6.1 illustrates a typical scenario where the rate of smooth bromegrass growth is faster than livestock are able to consume it in the first half of the growing season. This generally results in greater trampling and wastage of forage.  Later in the year, the rate of smooth bromegrass growth has slowed so that the rate of livestock intake exceeds what the plants are producing. Even though the season-long stocking rate may be correct, livestock are consuming mostly mature, poor quality forage.  Variable stocking rates can be used to better match forage supply and livestock demand by continually adjusting stocking rate throughout the season. To control livestock demand, livestock can be bought and added to the management unit early in the growing season when forage supply is high and then subtracted and sold later in the season when forage becomes limiting.  When applying variable stocking rates; however, continually buying and selling breeding livestock is not economically feasible as breeding livestock are capital assets that depreciate over time. Recapturing the investment in breeding livestock in a short-time frame, simply for the purpose of applying a variable stocking rate is not practical.  Use of a combination of breeding livestock and growing, yearling livestock, which are much more liquid, is a more practical method of applying a variable stocking rate. Yearling livestock can be held over from the previous years’

54

production or purchased off the open market. Castrated males or spayed females typically work better, as some intact females will likely be bred during the breeding season.

7000

Smooth bromegrass yield

6000

Fixed Stocking Rate

5000 4000 3000 2000 1000 MAY JUN JUL AUG SEP Figure 6.1. Rate of growth of smooth bromegrass outpaces rate of livestock consumption with a fixed stocking rate in June and July.

OCT

 Any number of yearling livestock can be used to implement a variable stocking system. The number of yearling livestock needed simply depends on how much flexibility the manager needs to build into the system. Generally, the ability to adjust stocking rate by 20% over the grazing season should be adequate to operate a successful variable stocking system.  As an example, if 70% of the grazing herd is composed of breeding livestock and the remaining 30% is made up of yearling livestock, the stocking rate can be adjusted by approximately 20% over the course of the grazing season by selling off the yearling livestock to match forage supply and livestock demand.  The actual amount your stocking rate can be adjusted in a variable stocking system is based on the percentage of both mature females and yearling livestock in the herd and live weight of each.  Table 6.1 is an example worksheet that calculates the amount stocking rate can be reduced in a variable stocking system.

55

Table 6.1. Example calculation to determine the amount stocking rate can be reduced in a variable stocking system.

Number of grazing animals in herd

300

A

Percent mature females (35% = 0.35)

0.7

B

Percent yearling livestock (35% = 0.35)

0.3

C

Live weight of mature females

1400

D

Live weight of yearling livestock

750

E

AxB

210

F

FxD

294,000

G

AxC

90

H

HxE

67,500

I

G+I

361,500

J

I/J

18.7

% SR can be reduced

ď&#x192;ź Table 6.2 can be used to calculate the amount stocking rate can be reduced in your variable stocking system.

56

Table 6.2. Worksheet for calculating stocking rate flexibility in a variable stocking system.

Number of grazing animals in herd

A

Percent mature females (35% = 0.35)

B

Percent yearling livestock (35% = 0.35)

C

Live weight of mature females

D

Live weight of yearling livestock

E

AxB

F

FxD

G

AxC

H

HxE

I

G+I

J

I/J

% SR can be reduced

57

Forage Supply Complementary grazing systems to extend the grazing season No single forage can supply the nutritional requirements of grazing livestock for more than a few months during the grazing season. The quantity and quality of any given forage continuously changes as the plants grow and mature. By combining different types of forages together in a system, the amount of time during the year when forage quantity and quality is adequate to support animal nutritional requirements will increase.  Sequentially grazing compatible forage types to optimize the advantages and minimize the disadvantages of these forage types is referred to as a complementary grazing system.  When considering a complimentary grazing system, complimentary forages should meet at least one of the following criteria: 1. Extending the green growing season 2. Diversifying a forage system by using variety of different forage types throughout the growing season can help minimize annual fluctuations in forage production and therefore, reduce production risk.

3. Increased production per unit of land area 4. Improved forage quality for better animal performance 5. Reduce overall production costs or a more cost-effective means of filling a need, thereby increasing profitability.  These criteria can be met using a variety of different forage types that can link the gaps in dominant forage types, extend grazing into the “off-season”, or simply supplant traditional forage sources at a lower cost of production.

Year-Round vs. Growing Season Complimentary Forages  Complementary forage systems can be formulated using any combination of resources ranging from native rangeland to seeded annuals. Selection of forage species in a complementary system should be based on optimizing resources that are already available.  Therefore, complementary systems in eastern South Dakota will look much different than complementary systems in western South Dakota. For example, in eastern South Dakota, a complementary grazing system could include the use of winter annuals (e.g. wheat, rye, triticale) may proceed turn out onto cool-season 58

pastures in early-May. Warm-season grass pastures or summer annuals can be subsequently grazed from early-June to September. Oat pasture or winter wheat could be grazed through mid-October or until turn-out on crop residues is possible. ď&#x192;ź A complimentary system in western South Dakota may include summer range, sorghum or cereal grain residue and winter range.

Figure 6.2. Cold weather can increase cow nutrient requirements. Photo: Eric Mousel

Figure 6.3. Stockpiling winter range can be an economical way to cut feed costs. Photo: Eric Mousel.

Grazing Alternative Forages Warm-season annuals

59

Millet  Millet species such as pearl millet, foxtail millet, and proso millet can be excellent forages for grazing and hay, although pearl millet is generally considered superior because of its excellent curing in haying situations and regrowth potential for grazing.  Millet yields typically are a little lower than sudangrass and forage sorghum hybrids, but if growing conditions are good, millet can produce yields close to that of the sorghum hybrids (Table 6.3).  Forage quality of millet varieties are comparable to sudangrass and forage sorghum hybrids, although on average, millets have slightly higher crude protein concentrations but slightly lower total digestible nutrients (Table 6.4).

Table 6.3. Dryland annual forage production for hay comparing pearl millet hybrids (HyPro and Mil-Hy 100) with other annual forage crops at the NDSU-Minot Research Extension Center from 1987-1989 (Sedivec and Schatz 1991).

Plant species

Pearl Millet: (Hy-Pro) (Mil-Hy 100)

(Siberian) (German) (Manta) Proso Millet**: Sudangrass**: sudangrass**: Sorghum**:

Average Dry plant matter* 70% moisture height yield/ac yield/ac (D.M.) (1987-1989) (1989) (1987-1989) ------in----------T------------T----34.6 29.3

2.5 1.9

9.2 (2.76) 8.6 (2.58)

Foxtail Millet: 27.0 2.8 25.7 2.3 24.0 2.3

8.0 (2.40) 7.6 (2.28) 7.2 (2.16)

33.0 54.8 Sorghum46.5 41.9

2.5 1.8

6.2** (1.86) 7.7 (2.31)

2.2 1.7

8.2 (2.46) 7.5 (2.25)

*No data was collected in 1987, average is for only the two years 1988 and 1989. **Data is the average for all varieties tested.

 Although pearl millet is not typically thought of as a prussic acid producer, it does tend to be a high nitrate accumulator. Therefore, pearl millet should always be tested for nitrates before grazing or haying, especially the regrowth.

60

ď&#x192;ź Allow at least 24-30 inches of growth before initially grazing or haying pearl millet and allow at least 18 inches of regrowth before grazing pearl millet again.

Sudangrass, forage sorghum and forage sorghum hybrids Table 6.4. Dryland annual forage production for hay comparing pearl millet with other annual forage crops at the NDSU-Carrington Research Extension Center from 1986-1989 (Sedivec and Schatz, 1991).

Forage crop

Plant height inches

ADF NDF Protein TDN ---------------------------%----------------------

Dry matter yield/ac tons

Pearl millet: (Hy-Pro) 1986 1987 1988 1989

63.6 76.0 33.7 30.2

--35.8 40.2

--58.5 62.0

--16.4 16.3

--55.3 50.2

4.13 7.63 1.29 2.09

Foxtail millet: (Siberian) 1986 1987 1988 1989

39.6 31.7 27.6 25.2

--38.3 39.1

--66.2 64.4

--12.6 10.9

--52.3 51.4

3.27 4.13 2.15 3.18

Proso millet: 1986 1987 1988 1989

53.3 44.0 36.4 30.4

--33.8 43.8

--54.2 65.0

--13.8 10.8

--57.5 46.0

2.63 4.36 1.70 2.94

Sudangrass 1986 1987 1988 1989

85.0 82.3 46.7 39.1

--30.1 27.8

--60.6 55.5

--11.6 9.4

--65.2 66.8

3.81 5.05 1.86 2.17

Sorghumsudan: 1986 1987 1988 1989

89.1 96.7 46.9 47.5

--33.1 29.2

--62.1 58.3

--11.1 10.7

--63.0 65.9

4.51 6.95 1.63 2.62

61

 Sudangrass, forage sorghum, and forage sorghum hybrids are an excellent dryland forage crop because of their high drought tolerance.  New BMR (brown mid-rib) varieties have improved forage quality dramatically.  Forage quality of sudangrass and the forage sorghums is competitive with corn silage (Table 6.5).  The biggest management concern with these forages is prussic acid poisoning or hydrogen cyanide poisoning.  Prussic acid concentrations are the highest in very young, quickly growing plants.

The concentrations dissipate quickly as the plant matures. Once plants have reached 20-24 inches tall, prussic acid concentrations in these forages are no longer high enough to be toxic to livestock.

Table 6.5. Forage yield of four grasses grown at two locations under two harvest management systems in 1986 (Tidwell, 2002).

Brookings Highmore Boot Early heading Boot Early heading ------------------------------------tons/acre-------------------------------------Siberian millet 1.3 3.7 3.0 4.6 German millet 3.5 5.9 4.6 6.2 Sudangrass 5.7 9.7 122 11.2 Teff 4.7 5.3 4.3 4.6  Prussic acid concentrations can be particularly high in regrowth of these forage species.  Drought conditions can increase prussic acid concentrations beyond normal levels.  Prussic acid concentration will spike following first frost and concentration will quickly decline over the week following a frost event.  Prussic acid is rarely found in hays or silages cut from these forage types.  Nitrates can also be problematic in these forages, especially in the regrowth following initial hay or silage harvest. Always test for nitrate levels before grazing these species.  Nitrate concentrations tend to increase in forages growing on dry soils or during droughts.  Nitrate concentrations will spike following first frost but will quickly dissipate in the week following the frost event.

62

 Nitrate concentrations above 2 ppm are generally considered to be toxic to livestock, especially pregnant cows.

Corn  Grazing standing corn can be option for some operators to either increase production per acre or take advantage of a failed corn crop. One of the major advantages of grazing standing corn is it is extremely flexible as to when it can be grazed. Fall and early winter grazing is typical, but with the height the corn plant has, it can be a useful forage even in fairly deep snow.  Any hybrid variety of corn can be grazed by cattle, but if corn is planted specifically for grazing purposes, varieties developed for grazing probably are best suited.  Silage yields in South Dakota vary significantly with 15 tons per acre common in the far east and 8-10 tons on average in the central part of the state. Corn yields west river are very dependent upon soils and rainfall but average in the 5-8 tons per acre range.  Nitrates and founder (acidosis) in ruminants are the two biggest management concerns for livestock producers.  Corn should be tested for nitrates before grazing. Nitrate levels above 2 ppm are generally considered toxic to ruminants, especially pregnant cows.  Livestock should be acclimated to a diet containing corn grain before turnout on standing corn to adequately adjust the digestive system to high energy concentrations.  Feeding an ionophore such as Rumensin or Bovatec also is cheap insurance against acidosis and bloat however, delivery to grazing livestock can be expensive.

Teff  Teff (Eragrostis tef Zucc. Trotter) is a major cereal crop in Ethiopia and has been grown in other African countries as a hay crop. Teff is a warm-season, annual grass that has rapid seed germination and seedling development. It also is well adapted to dry climates. These qualities indicate that teff could be used in this region of the U.S. as a supplemental forage during periods when other forage supplies are diminished. In South Dakota, late summer is when forage supplies are typically low.

63



In trials conducted at SDSU, teff yields reasonably well when compared to Siberian and German millet (Table 6.6).

 

Forage quality of teff is comparable to millet (Table 6.7).

Teff does appear to be susceptible to Eurytomocharis eragrostidis, a stem boring wasp and little information is available on how to control this problem in South Dakota.

Table 6.6. Crude protein and In-vitro digestible dry matter (IVDMD) of four grasses grown at two locations under two harvest management systems in 1986 (Tidwell 2002).

Crude protein IVDMD Brookings Highmore Brookings Highmore ------------------------------------%-------------------------------------Siberian millet 9.2 12.2 67.1 59.1 German millet 8.9 12.6 58.7 53.2 Sudangrass 9.7 12.4 56.1 53.9 Teff 10.7 17.4 54.0 51.2 Table 6.7. Dry matter (DM), total digestible nutrients (TDN), net energy for gain (NEg), net energy for maintenance (NEm), and crude protein (CP) of sorghum type forages (Undersander 2001).

100% Dry Matter Basis DM TDN NEg NEm CP % % kg kg % Grain Sorghum Silage 30 60 1.31 0.74 7.5 Forage Sorghum Sorgo 27 58 1.24 0.68 6.2 Sudangrass Fresh, Early Vegetative 18 70 1.63 1.03 16.8 Fresh, Midbloom 23 63 1.41 0.83 8.8 Hay, sun-cured 91 56 1.18 0.61 8 Silage 28 55 1.14 0.58 10.8 Corn Silage Corn Silage (well-eared) 33 70 1.63 1.03 8.1 Grazing cereals grains and annual legumes Cereal grains

64

 Potential forage crops in this category include wheat, triticale, rye, oats, and barley. Winter annuals are planted in the fall and grow in the cool season and are less likely to encounter drought. Small grains can provide excellent fall or early spring pasture. Spring-seeded small grains can provide late-summer pasture.  Grazing before jointing begins will allow for continuous leaf development and prolong the grazing season.  Nitrates and grass tetany are two management concerns with using cereal grains for forage.  Cereal grains should be tested for nitrates prior to haying or grazing. Nitrate concentrations in excess of 2 ppm are generally considered to be toxic to livestock, especially pregnant cows.  Grass tetany is caused by an imbalance of calcium as a result of low magnesium concentrations. Tetany most often occurs when forages are very lush and growing rapidly. Tetany problems are mostly associated with spring forage growth, however, tetany in the fall can be as big of a problem as in the spring.  Livestock grazing on lush, rapidly growing forages in spring or fall should provided supplemental magnesium. The use of “Hi-Mag” mineral tubs or loose mineral is common for this purpose.  Yields of forage from cereal grain species is often 1.5-2.5 tons per acre when grazed or harvested between the joint and boot stage. Additional yield can be captured if harvest is delayed until milk stage, but forage quality will have declined significantly by this time.  Forage quality of forage from cereal grain species is excellent, often providing as much as 20% crude protein and in vitro digestibility of around 80% (Table 6.8).

Table 6.8. Crude protein (CP), acid detergent fiber (ADF), neutral detergent fiber (NDF), and in-vitro digestible dry matter (IVDMD) of cereal grain species and annual legume species (Nleya and Jeranyama 2005).

Forage species CP ADF NDF IVDMD --------------------------------%------------------------------Barley 9-11 43 65 64-69 Oats 8-10 34 65 56-74 Triticale 8-10 36 66 53-70 Rye 7-9 27 49 50-56 Wheat 9-11 32 60 58-64 Field pea 16-21 33 40 65-71 Cow pea 19-24 22 36 69-78 Mungbean 16-23 --60-78

65

Annual legumes  Bloat is always a concern when livestock are grazing legumes. Using bloat protection products that contain proloxalene such as Bloatgaurd® in the lick block form will minimize this risk.  Using ionophores such as Rumensin® or Bovatec® will also minimize bloat problems however; delivery of these products can be more difficult than proloxalene products.

Field peas  Field pea is a cool-season legume commonly grown in mixtures with cereal forages to increase crude protein levels and improve digestibility of the forage.

Field pea can be mixed with oats, barley, or triticale.  Cereal/pea mixtures should be harvested based on developmental stage of the grain. For heifers and beef cattle, harvest at soft dough stage. The pea in the mixture at harvesting should be at early to mid-podding stage.

Cow peas  This warm-season crop also known as blackeyed peas and is widely grown in the southern U.S. Research at SDSU has shown that cowpea is well adapted to South Dakota conditions.  The crop is more drought tolerant than field pea and therefore has a special fit to western South Dakota conditions. Cowpea can be used for hay or silage. When used for hay, cut when most pods are fully formed. Dry matter yield in South Dakota has ranged from 1.9 to 3.1 tons per acre.

Mungbeans  Mungbean is a warm season legume that tolerates heat and drought but has lower dry matter yields than cowpea.  Research at SDSU indicates that this crop is well adapted to local conditions, with yields ranging from 0.8 to 1.8 tons per acre.

Grazing cover crops

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Brassicas  Turnips, radishes, lentils are in the Brassica family and represent a quality forage for livestock that is cheap and relatively easy to grow to extend the grazing season in the fall.  Brassicas are not particularly drought tolerant therefore; their use is generally limited to the eastern one-half of South Dakota.  Yield of brassicas varies based on annual precipitation, but can yield as much as 2 tons of dry matter per acre (Table 6.9).

Table 6.9. Forage yield (lb./acre) from turnip tops and bulbs planted in August 2003 and fertilized with 75 pounds of nitrogen per acre at Brookings, SD (Smart et al. 2003).

Planting date1 Plant part August 1 August 15 Tops 2910a 360b a Bulbs 1050 30b Total 3960a 390b 1 Means followed by same letter within a row are not significantly different at P < 0.05.

SE = standard error of the mean.

SE 202 112 307

 Forage quality of brassicas is high, especially in terms of crude protein which can often run in excess of 15% (Table 6.10).  High moisture content of forage from brassicas can limit livestock performance, especially in young, growing animals. Planting brassicas with a cereal grain like oats is recommended to decrease moisture content of the diet.  Brasicas do not present many management challenges to livestock; however, turnips can cause Atypical Interstitial Pneumonia (AIP) in livestock. It is rare, but it does happen occasionally, especially in turnip monocultures. Strip grazing monocultures for 5 to 7 days to acclimate animals to this diet will help control this problem.

Grazing crop residues  Relatively large amounts of crop residues are produced annually in South Dakota.

Crop residue is the portion of the harvested crop that remains after the marketable portion of the plant is removed. Potential crop residues include corn stalks, grain sorghum residue, wheat, rye, and millet stubble, soybean residue, and turnip tops.

Stocking rates on various crop residues are given in Table 4.4 in Chapter 4.  Quality of crop residues generally is considered inadequate to provide for much weight gain in young, growing animals unless significant grain remains in the

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field after harvest. Furthermore, some crop residue may not provide sufficient nutrient maintain weight in mature animals as the grazing season progresses.

Table 6.10. Neutral detergent fiber (NDF), acid detergent fiber (ADF), and crude protein (CP) from turnip tops and bulbs harvested from the August 1 planting date in October and November 2003 at Brookings (Smart et al., 2003).

Plant part Tops NDF ADF CP Bulbs NDF ADF CP

Harvest date1 October 15 November 1

SE

19.8a 16.8a 15.3a

21.5a 18.3a 14.5a

2.19 2.02 0.79

24.7a 21.0a

12.7a 10.5a

3.18 3.06

15.4a

12.8b

0.24

1

Means followed by same letter within a row are not significantly different at P < 0.05.

SE = standard error of the mean.

 Therefore, supplementation of livestock on crop residues likely will be necessary to maintain adequate performance.  Natural proteins such as those from soybean, cottonseed, and sunflower are preferred to supplements that contain non-protein nitrogen (urea) that must be converted to protein in the rumen. To convert nitrogen to protein, the rumen must have a readily available energy source. Low quality crop residues do not generally provide ample amounts of available energy to facilitate this process. Use of natural protein sources with crop residue programs will improve diet digestibility, intake, and potentially animal performance.

Grazing winter range/stockpiled forages  Winter feeding costs can account for 60% to 75% of the total cost of producing a calf in South Dakota. One option to reduce the amount of mechanically harvested and fed forages is to stockpile pastures or rangeland for grazing during winter.  Stockpiling forage is accomplished by deferring pastures from grazing for the remainder of the growing season after a grazing period early in the growing season. The accumulated forage from these pastures can then be used for grazing following the first killing frost.  When stockpiling forages for use during the winter, the objective is to provide as much leaf material as possible to grazing animals. Leaf material is more readily eaten and generally is higher quality than stem material. Furthermore, excessive stem material can reduce intake of grazing animals.

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ď&#x192;ź In general, stockpiled forages and dormant range will be moderate or poor quality forage. These forages likely will not meet the nutrient requirements of growing animals or lactating females without protein supplementation. However, stockpiled forages or dormant range can be an economical way to feed livestock for most of the winter months (Figure 4.5).

References Hoyt, C. and D. Odekoven. 1994. South Dakota beef herd profitability 1986-1993. South Dakota Beef Report. South Dakota State University. Brookings, SD. Mousel, E.M. 2005. Ecology and management of Sandhills rangeland: Fall grazing of uplands and ecosystem dynamics of subirrigated meadows. Dissertation. University of Nebraska â&#x20AC;&#x201C; Lincoln. Lincoln, NE. Nleya, T. and P. Jeranyama. 2005. Utilizing annual crops for forage in western South Dakota. South Dakota State University cooperative Extension Service. South Dakota State University. Brookings, SD. ExEx8152.

Sedivek, K. and B. Schatz. 1991. Pearl millet forage production for North Dakota. North Dakota State University Cooperative Extension Service. North Dakota State University. Fargo, ND. R-1016.

Smart, A., P. Jeranyama, and V. Owens. 2003. The use of turnips for extending the grazing season. South Dakota State University Cooperative Extension Service. South Dakota State University. Brookings, SD. ExEx2043.

Tidwell, E., A. Bow, and D. Casper. 2002. Teff: A new annual forage for South Dakota.

South Dakota State University cooperative Extension Service. South Dakota State University. Brookings, SD. ExEx8071.

Undersander, D. 2001. Sorghums, sudangrasses and sorghum-sudangrass hybrids for forage. University of Wisconsin Cooperative Extension Service. University of Wisconsin. Madison, WI. http://www.uwex.edu/ces/forage/pubs/sorghum.htm.

Wright, C. and K. Tjardes. 2004. Grazing corn stalks. South Dakota State University Cooperative Extension Service. South Dakota State University. Brookings, SD ExEx2044.

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Chapter 7 Basic Principles of Grazing Management Grazing management is the manipulation of grazing animals to accomplish desired results in terms of animal, plant, land, or economic response objectives. Effective grazing management requires a comprehensive plan to secure the best practical use of forages resources. A grazing plan must provide for the daily, seasonal, and annual grazing capacity needs of livestock and/or wildlife and must match the quantity and quality of forage produced with the needs of the animals grazing it. The objectives of the grazing plan should include long-term sustainability as well as immediate profitability of production.  One of the primary reasons we attempt to manage the grazing activities of animals is because they are very selective in what they eat. Grazing animals choose to harvest different plant species, individual plants, or plant parts to the exclusion of others that are available to them as discussed in Chapter 3.  Selective grazing allows animals to graze some areas down while other areas are allowed to go to seed. As soon as key forage species begin to regrow after having been grazed, grazing livestock will return and graze those same plants again since they are higher quality than forage species that have not been previously grazed.  When animals are allowed to select their own diet, pasture utilization is poor because, areas that are allowed to fully mature are never grazed by livestock because forage quality is too low. Areas that are repeatedly grazed never get a chance to reach the rapid growth phase which reduces overall forage production.

Selective grazing also results in poor forage species composition in pastures. The highest-quality species are repeatedly grazed by livestock and die out of the stand from overgrazing. The less desirable plants will be refused by livestock and will flourish.  Managing the grazing activities of livestock allows producers to better control the level of diet selection and increase pasture utilization. In addition to decreasing selectivity of livestock, the objective of managed grazing is to control the intensity, frequency and timing of defoliation within a pasture to improve regrowth potential of key forage species.  The time of the year in which a pasture or individual plant is grazed has a great effect on the severity of grazing it can tolerate. Timing the use of initial pasture growth with conditions that are optimum for regrowth and managing intensity and frequency of defoliation by using tightly controlled periods of grazing and periods of recovery will optimize both pasture productivity and animal performance.

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Logistically however, not every pasture can be grazed when conditions are optimum for regrowth.  Some pastures will need to be grazed when conditions for regrowth are poor.

Therefore, a key component of grazing management is to ensure that individual pastures are not grazed at the same time of year in subsequent years.  Grazing intensity, in general, refers to the amount of livestock demand that placed upon the pasture and to the amount of vegetation removed during the grazing period. Intense grazing by itself may not be detrimental to forage plants; however, sustained intense grazing can reduce productivity and vigor of key forage species over time.  We can manage grazing intensity by using appropriate stocking rates.  Grazing frequency refers to the number of times a pasture or individual plant is defoliated during the growing season and is interrelated with intensity and selectivity of grazing. Plants that have been grazed earlier in the growing season and allowed to regrow are often selected by livestock again during the next grazing period. The more times a plant is grazed during the growing season, the more intensely it is grazed. Frequency of grazing can be controlled by arranging periodic intervals of rest for the pasture to allow plants time to recover.  The two primary tools used to control timing, intensity, and frequency of grazing are stocking rates and grazing systems. Selecting the proper stocking rate allows us to control the intensity of grazing.  Stocking rates allow us to manage the amount of leaf material that is removed by grazing livestock and more importantly, the amount of leaf material remaining to produce energy for regrowth. Using a stocking rate that is too high, too little leaf area will remain for plants to produce energy and regrowth will be slower. If the stocking rate is too low, leaves mature and fibrous stems are produced reducing photosynthetic efficiency and forage quality.  Grazing systems allow us to determine the manner in which grazing and recovery periods are arranged within the grazing season to control selectivity and frequency of grazing. As we discussed in Chapter 2, plants need green, growing leaves to photosynthesize and produce energy for growth and reproduction.  The primary goals of grazing management is to manage the amount of leaf material available for photosynthesis in pastures and to maintain as many acres of growing leaves for as many days of the year as possible.  The amount of leaves available in pastures can be influenced through the use of tightly controlled grazing periods and recovery periods.

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Figure 7.1. Using stubble heights of key forage species. Photo: Eric Mousel

Length of grazing periods  Controlling the amount of time animals are allowed to graze a pasture is just as important as the amount of time a pasture is given to recover. When grazing periods become too long, forage species may regrow enough leaf material to be regrazed again within the same grazing period and may be damaged as a result.  The recommended stocking rate for a specific site will allow us to adequately manage forage use over the entire grazing season. However, not all of the forage that a pasture will produce is available at one time, it accumulates over the growing season.  In the eastern one-third of the state, many forage species grow so rapidly that pastures must be grazed multiple times throughout the growing season to efficiently use all of the forage. In the western two-thirds of the state, forage species grow much slower and produce much less yield.  Often times efficient utilization of forage can be achieved by grazing each pasture only once during the season. Use of recommended stocking rates does not always clearly indicate when the best time to begin a grazing period or when it is time to remove animals, especially in more intensive management systems. In addition to

72

using recommending stocking rates, other indicators of forage response to grazing should be used to manage grazing and rest periods. ď&#x192;ź Average plant height is a simple way to determine when grazing should be begin and end (Figure 7.1). Appropriate average plant heights differ greatly in different areas of the state, with different plant species and photosynthetic pathways (Table 7.1). The important thing to remember is to avoid overgrazing key forage species within a pasture. ď&#x192;ź The shorter a pasture is grazed, the longer the rest period required for forage recovery. A good rule of thumb to maintain adequate leaf material for rapid recovery from grazing is to leave 2 to 4 inches of stubble for short cool- and warm-season grasses and 4 to 6 inches of stubble for taller cool- and warm-season grasses.

Table 7.1. Average plant height to begin and end grazing periods (adapted from Undersander et al. 2002).

Species grazing

Plant height (inches) Start grazing Stop

Tall, cool-season grasses (introduced) smooth bromegrass, intermediate wheatgrass, reed canarygrass, orchardgrass

8-10

4-6

Short, cool-season grasses (introduced) Kentucky bluegrass, crested wheatgrass

4-6

2

Tall, cool-season grasses (native) western wheatgrass, green needlegrass needleandthread

6-8

4

Short, cool-season grasses (native) Prairie junegrass

4-6

2

Tall, warm-season grasses (introduced) Sorghum/sudangrass

12-14

4-6

Tall, warm-season grasses (native) Big bluestem, indiangrass, little bluestem Tall dropseed, switchgrass

12-14

4-6

4-6

2

Short, warm-season grasses (native) Hairy grama, blue grama, buffalograss

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Length of recovery periods  The duration of the rest period necessary for a pasture to reach the desired height for another grazing period varies throughout the growing season.  In the eastern one-third of South Dakota, when growing conditions are good early in the grazing season, the rest period may be as short as 20 to 25 days for both cool- and warm-season grasses. Later in the season when it becomes hot and dry, 45 to 60 days may be required to ensure adequate rest before the next grazing period.  In the western two-thirds of the state, initial forage growth is relatively slow and regrowth following grazing is often limited. Grazing pastures in western South Dakota more than once per growing season may not be a very efficient or practical management system. In most years, pastures will require the remainder of the growing season and/or a portion of the following growing season to recover from grazing.  The above guidelines provide a good starting point for developing a grazing plan and making decisions on how long to graze pastures and how long pastures need to recover. But management must remain flexible to fit into individual management systems. A key part of proper grazing management is to move animals according to forage plant characteristics and animal performance, not a set calendar date.

References Anderson, B.E. 2000. Use of warm-season grasses by grazing livestock. Native WarmSeason Grasses: Research Trends and Issues. Crop Science Society of America and American Society of Agronomy Special Publication No. 30. Madison, WI. Mousel, E.M., W.H. Schacht, and L.E. Moser. 2003. Summer grazing strategies following early season grazing of big bluestem. Agronomy Journal. 95:1240-1245.

Morley, F.H.W. 1981. Management of grazing systems. In: F.H.W. Morley [ed.]. Grazing Animals. Elsevier, Amsterdam.

Undersander, D., B. Albert, D. Cosgrove, D. Johnson, and P. Peterson. 2002. Pastures for profit: A guide to rotational grazing. University of Wisconsin Cooperative Extension Service. Madison, WI. A3529.

Vallentine, J.F. 1990. Grazing Management. Academic Press Inc. San Diego, CA.

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Chapter 8 Grazing Systems Grazing systems are the manner in which periods of grazing and periods of recovery are arranged within the maximum feasible grazing season. The use of a grazing system employs the basics of grazing management to help producers accomplish their production goals of both the forage resource and animal performance.  Grazing systems are not a panacea that can solve all the challenges of managing both forage resources and grazing livestock.  Proper grazing management requires proper stocking rates, season of forage use, kind or mix of animals, and grazing distribution as well as an appropriate grazing system to be successful.

Ainsworth, Nebraska rancher Sid Salzman (1983) stated: “The ranch manager can make a good grazing system fail and a poor system work. To successfully implement a grazing system the manager should have a genuine interest in grass, a note at the bank, enough greed to want to make more money, willingness to take a chance, nerve enough to withstand criticisms of neighbors, willingness to accept and heed advice from technical people, and the time and inclination to observe and evaluate their program and to constantly update it. A successful grazing system must be flexible, fit the manager, the ranch, and the livestock.”  Grazing systems define periods of grazing and recovery, making an incredible number of potential grazing systems possible. Resource limitations segregate the number of feasible grazing systems into the following four categories: seasonlong continuous grazing, rotational grazing, rest-rotational grazing, deferred rotational grazing, and intensively managed rotational grazing.  Selection of a grazing system must take into consideration the forage species being grazed, the grazing season, the physiography of the grazing site, the nutritional needs of the kind and class of livestock to be grazed, and the management objectives of the operation (Table 8.1).

Season-long Continuous Grazing  Season-long continuous grazing allows livestock unrestricted access to a fixed pasture-unit of land throughout the majority of the grazing season (Figure 8.1).

75

 This system has a low capital investment cost, a lower stocking density (number of animals in a fixed area at any point in time) than other grazing systems, and Table 8.1. Selection criteria for choosing a grazing system that can help achieve management goals (adapted from Vallentine, 1990; Henning et al., 2000; Reece et al., 2001; and Blanchet et al., 2003).

Grazing System Season-long continuous

Advantages • Low investment • Low management risk • Increased average daily gains

Best Use • Flat, well watered range where forages have similar grazing value e.g. crested wheatgrass

Deferred rotation

•

•

• • •

Rest rotation

Intensively managed

Disadvantages • Poor forage utilization • Loss of key forage species • Increased labor to checked dispersed animals Maintain vigor of • Potential increase key forage species in fence and water costs Improved grazing distribution and • Lower individual forage utilization animal performance Provides nesting cover for game birds • Increased management risk Extended grazing opportunities in the fall

• Increased vigor of key forage species in rested pasture • Improved grazing distribution and forage utilization • Provides nesting cover for game birds

•

• Increased utilization of forage • Increased flexibility in achieving management goals • Improved control over forage quality

•

• • •

• •

Loss of some key forage species Potential increase in fence and water costs Lower individual animal performance Increased management risk

•

Increased fence and water costs Increased labor for monitoring forage resource Increased management risk

•

Most beneficial on rangeland in moderate range condition or where additional wildlife habitat is desired.

Deferments have limited utility on improved pastures or rangeland with very low range condition.

Rest rotations are most useful to solve specific problems.

Resting pastures is useful in situations such as: following reseeding or interseeding, providing fuel for prescribed burning, or use in conjunction with critical site rehabilitation.

Most useful in areas with fast growing forage species and high regrowth potential. Of marginal use in areas where forage growth 76

is slow and regrowth potential is low. generally requires the least management input because livestock remain on the same pasture throughout the grazing season.  Low stocking density at moderate stocking rates results in livestock selecting the highest quality plants and plant parts and some areas are grazed heavily to the exclusion of others. Continuous grazing can create a patchwork of grazed and ungrazed areas within the pasture, resulting in poor utilization.  Livestock have unrestricted access to repeatedly graze the highest quality plants in the stand. Although average daily gain for growing animals may be a little higher, the heavy grazing pressure on these higher quality plants could result in their disappearance from the stand over time. This will leave the less desirable grasses and weaken the overall stand allowing invasion by undesirable species.

Rotational Grazing  Rotational grazing involves the strategic movement of grazing animals through multiple grazing units based on the nutritional needs of the animals and the requirements for sustainable forage regrowth.  A standard rotational grazing system requires at least two paddocks, but a pasture divided into three or four paddocks is more common. These systems are generally a better match for rangeland and improved pastures in South Dakota than continuous season-long grazing systems. They allow managers to increase stocking density in individual paddocks and use sequential periods of grazing and rest to improve forage utilization by more closely matching rate of livestock intake to forage accumulation rate early in the grazing season and providing key forage species in the pasture with recovery periods (Figure 8.2).  Although initial capital investment costs and commitment to management is higher for rotational grazing systems, these costs are quickly recaptured through lower grass stand maintenance costs (reseeding, herbicides) and increased production from better forage utilization on both improved pastures and rangeland.

Deferred Rotational Grazing  Deferment prohibits grazing from the braking of dormancy until after seedset or equivalent vegetative reproduction. The objectives of deferment from grazing are to increase seed production, enhance seedling establishment, and to prevent overgrazing during low forage availability in early spring.

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ď&#x192;ź Grazing multiple pastures with one grazing period per pasture per year at recommended stocking rates is often an efficient method of maintaining key forage species, maintaining or improving range condition, and minimizing areas of heavy use (Figure 8.1).

Figure 8.1. Examples of grazing period and recovery period arrangements in season-long continuous, rest-rotation, deferred rotation, and intensively managed grazing systems (Reece et al., 2001).

MAY

JUN

JUL

AUG

SEP

OCT

Season-long Continuous

Rest-Rotation 1 2 3 4 5

Deferred-Rotation 1 2 3 4 5

Intensively Managed MAY

JUN

JUL

AUG

SEP

OCT

1 2 3 4 5 6 7 8 9

78

N u m be r of P as tu re s

10

Rested Grazed  Although higher stocking densities in individual pastures will improve overall forage utilization, improved grazing distribution will limit the availability of cover for wildlife. Because each individual pasture is only grazed one time per year, animal performance may suffer slightly in the last pastures grazed each season due to advanced plant maturity.  Dormant season and growing season grazing also can be rotated among pastures where possible: however, lack of protection from weather and other factors may limit the possibility of dormant season grazing. When appropriate, most key forage species can be maintained by delaying initial turnout until the onset of the rapid growth phase and providing periodic deferment of each pasture until after the first killing frost.  Pasture deferments should not be applied to improved pastures with intensive agronomic inputs. Deferments are generally unnecessary to maintain vigor in improved pasture and often times will shorten the green growth period because of extensive litter build up. Reduced forage quality and excessive wastage also may result because forage accumulation rate often times will exceed intake rate of grazing livestock resulting in relatively mature forages.

Rest Rotational Grazing  This system was initially developed to improve range condition by requiring at least one full calendar year of non-grazing for one pasture in the system (Figure 8.1). In some cases rest is continued through a second year or applied in alternate years. The pasture that is rested is then rotated among the pastures in the system in subsequent years.  Stocking rates are typically increased in grazed pastures to compensate for the unused forage in the rested pasture. Increased stocking density in grazed pastures will improve grazing distribution and ultimately forage utilization, but also will result in reduced animal performance in the last one or two pastures grazed each year compared to other rotation systems.  The use of a full calendar year of rest as a routine maintenance technique included in a grazing system is often considered unnecessary and an inefficient use of forage. The primary use of a rest rotation likely should be as a management tool to remedy specific problems. Resting pastures is useful in situation such as following reseeding or interseeding of pastures, providing fuel for prescribed burning treatments, or in conjunction with critical site rehabilitation associated with historic overgrazing or heavy traffic areas.

79

 Rest rotation grazing systems also can be used to increase habitat for wildlife.

Each spring, the rested pasture and the pasture grazed first during the preceding year will provide the greatest amount of nesting cover for upland game birds.

Deferred grazing in these pastures until mid-June or early July will ensure optimal use of nesting or brood-rearing cover.

Intensively Managed Rotational Grazing  Intensively managed rotational grazing systems allow the manager much more flexibility in managing animal movements through a series of smaller paddocks and adjusting the length of grazing and recovery periods through the grazing season (Figure 8.1).  In an intensively managed system, generally > 8 to 12 paddocks are used.

Increasing the number of paddocks and decreasing the size of paddocks increases the stocking density, resulting in more uniform grazing, higher quality regrowth, and provides more flexibility to manage rapid rates of grass growth.  Because the number of animals in a paddock in an intensively managed system is increased compared to other rotational systems, animal movements are more frequent, allowing the manager to better match livestock intake rate with forage accumulation rate.

Figure 8.2. Increased stock density helps to more closely match animal intake with forage accumulation to improve forage utilization. Photo: Eric Mousel.

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 Initial animal movements through paddocks may be as frequent as every 1 to 5 days in the early season, depending on the number of paddocks available. As the season progresses, movements may slow to every 1 to 2 weeks, to allow adequate recovery periods for each paddock. However, with relatively high grazing pressures on individual paddocks and numerous decisions of when to begin and end grazing periods, intensively managed grazing systems require a high level of commitment to monitoring pastures and managing livestock movements.  Intensively managed grazing systems have been successfully adapted to both arid and semi-arid rangelands, however, they are probably less useful on the semi-arid rangelands of western South Dakota than in sub-humid areas of the eastern part of the state because of slower growing grasses, limited regrowth potential, and much larger acreages that generally making fencing and water development cost prohibitive.

Grazing Systems for Special Situations Flash Grazing  Flash grazing is the practice of moving livestock over grazing areas quickly to allow them to consume the highest quality forage over a very short amount of time before moving them to the next area.  Although flash grazing can be a time intensive practice to the grazing manager, its utility lies in taking advantage of early germinating, fast growing forages in the early-season, such as cheatgrass, before the bulk of the season’s vegetation begins spring growth.  Flash grazing is typically applied at much higher stocking densities than the recommended stocking rate would apply resulting is quick and efficient forage use over a short period of time.

Strip Grazing  Strip grazing involves moving livestock every 1 to 3 days to a new grazing unit of fresh forage.  Long strips of pasture are divided by moveable front and back fences (often consisting of a single strand of electric fence) to ensure complete forage usage.  The front fence keeps the animals from advancing until the planned move while the back fence keeps animals off the previously grazed strip to allow undisturbed pasture regrowth.

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 Grazing is very short term where grazing animals are concentrated under a high stocking density to limit forage refusal.  Strip grazing is generally limited to intensive, land-limited, high production enterprises such as alfalfa – orchardgrass pasture, cereal grain forage (oats, rye, triticale), or other high producing forages where significant wastage is a concern (i.e. sudangrass, millet, corn) to justify the high degree of management and investment required.

Intensive-Early Stocking  Intensive-early stocking (IES) is a grazing system that has incorporated the advantage in growing livestock gains from concentrating grazing in the early part of the growing season.  This 1-pasture system is generally used on native grass range in the Midwest and is based on high stocking density during the rapid growth phase associated with grass vegetation found in this region.  Grazing is discontinued at seed set (early- to mid-July), allowing grass plants to make full plant recovery for the rest of the growing season while not reducing the standing crop the next year.  IES is generally based on double stocking density (2X) during the first half of the normal growing season, thereby maintaining the same stocking rate (acres/AUM) as under Season-long Continuous grazing.  The biggest advantage of the IES system is greater forage use efficiency early in the growing season compared to late in the growing season.  IES is well suited for weaned, growing livestock, but is not practical nor necessary for breeding females.

Creep Grazing  Creep grazing permits suckling calves or lambs access to higher quality forage than is available to the dam.  Young calves or lambs are allowed to creep into the next pasture or allotment while the dams are held back by the forward creep fence. This system is most

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often used in combination with a strip grazing program on high producing, high quality forage.  When the mature female herd moves into the next pasture or allotment, the forward creep fence is moved so young animals have access to the next pasture or allotment.  It has been noted that calves are unable to compete with their dams to maintain high quality forage intake even at moderate stocking rates. However, the use of lower stocking rates to favor the calf is impractical because of the reductions in production per acre.  Creep grazing provides an opportunity to increase weaning weights through the higher consumption of forage nutrients by the calf to supplement the milk obtained from the dam; reducing or eliminating the use of expensive, inefficient concentrate feeds.

References Blanchet, K., H. Moechnig, and J. DeJong-Hughes. 2003. Grazing Systems Planning Guide. University of Minnesota Cooperative Extension Service. University of Minnesota. St. Paul, MN. Heady, H.F. 1974. Theory of Seasonal Grazing. Rangeman’s J. 1(2):37-38.

Heady, H.F. 1984. Concepts and principles underlying grazing systems. In: National Research Council/National Academy of Sciences, Developing strategies for rangeland management. Westview Press. Boulder, CO. Henning, J., G. Lacefield, M. Rasnake, R. Burris, J. Johns, K. Johnson, and L. Turner.

2000. Rotational Grazing. University of Kentucky Cooperative Extension Service.

University of Kentucky. Lexington, KY. Kothmann, M.M. 1980. Integrating livestock needs to the grazing system. In: K.C. McDaniel and C. Allison [eds.]. Grazing management systems for southwest rangelands: A symposium. Range Improvement Task Force. New Mexico State University. Las Cruces, NM. Lewis, J.K. 1983. Tentative classification of grazing systems. Society of Range Management. Abstract Papers. 36:231.

Mousel, E.M. 2005. Ecology and management of Sandhills rangeland: Fall grazing of uplands and ecosystem dynamics of subirrigated meadows. Dissertation. University of Nebraska – Lincoln. Lincoln, NE.

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Reece, P.E., J.D. Volesky, and W.H. Schacht. 2001. Integrating management objectives and grazing strategies on semi-arid rangeland. University of Nebraska Cooperative Extension Service. University of Nebraska â&#x20AC;&#x201C; Lincoln. Lincoln, NE. EC01-158.

Salzman, S.E. 1983. Steps and requirements in establishment of grazing systems.

Rangelands. 5(5):212-213.

Stoddart, L.A., A.D. Smith, and T.W. Box. 1975. Range Management. [3rd ed.]. McGrawHill. New York, NY. Vallentine, J.F. 1990. Grazing Management. Academic Press Inc. San Diego, CA.

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Chapter 9 Setting Grazing Goals and Selecting a Grazing System to Achieve Those Goals Ultimately, grazing systems are designed to accomplish management objectives based on known available resources, ecological considerations and economic drivers. Management of grazing can be greatly simplified when goals are based on clearly stated and prioritized natural resource, livestock production, and financial management goals.

Defining objectives  Grazing management objectives can be classified into six major categories (Figure 9.1).  Once these objectives have been prioritized by the grazing manager, goals and expected outcomes can be set.  Not every possible combination of grazing management objectives is included in these categories. However, these are the major management objectives with known effects on a particular grazing system.  Through grazing research the ability of a particular grazing system to achieve each management objective can be predicted.  The predictability of a particular grazing system to achieve certain objectives gives the grazing manager the opportunity to tailor grazing strategies and systems to their management goals and desired or expected outcomes.

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Figure 9.1. Grazing strategies should be based on prioritized objectives that can be classified into six major categories.

Goal setting  Once the grazing management objectives have been prioritized, the process of developing grazing goals can begin based on these objectives.  Prioritizing management objectives can be challenging because every objective seems as important in the next; however, no one grazing strategy can meet every conceivable grazing objective.  Therefore, a manager must decide the things that are important to the long-term health of the land and the operation, which things are mutually exclusive, and which things just aren’t that important.

Example  A grazing manager runs about 500 cows on his rangeland, but is working towards developing a bird watching enterprise on their operation so they can charge a fee for folks from Denver and Minneapolis to come and enjoy a variety of different grassland bird species.  This manager wants to maintain current levels of livestock production, but needs to provide habitat at certain times of the year to attract and keep grassland bird species population high in the area.

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 The manager is very inclined to take on management risk and is willing to invest some labor to make this work. The manager is also willing to invest capital in infrastructure, but financially needs to keep it pretty low.  There are obviously a lot of factors to consider that won’t be covered in this example; however, from a grazing perspective, which four or five objectives should be the most important to achieving the ultimate goal?  Referring back to Figure 9.1, the most important grazing objectives to achieve the ultimate goal in order of priority might look like this: Objective 1: Maintain current levels of livestock production.

Objective 2: Improve vegetation cover for wildlife habitat.

Objective 3: Improve vegetation diversity to increase numbers of grassland bird species.

Objective 4: Keep investments to a minimum  Now that objectives are prioritized, this manager can set the goals they think will lead to success if they are achieved.

Selecting the grazing system that will achieve grazing goals  Once objectives and goals have been established, you can now determine which grazing system will best achieve those goals.  To determine which grazing system is most likely to achieve the goals you have set for your outfit, you can use a decision support matrix that was originally designed by Reece et al., 2001.  This decision matrix has been modified to more accurately reflect the grazing environment in South Dakota and has incorporated vegetation response data from studies conducted in South Dakota, North Dakota, and Nebraska.  The purpose of this matrix is to help select a grazing system that will most likely achieve grazing goals by taking into account how those goals have been prioritized in terms of importance to achieving your goals.  In order to be able to use the decision matrix, grazing management objectives need to be ranked using a simple weighting method. The weighting method allows for comparison of the relative value of a given objective to each of the other objectives.  Divide 10 points amongst the chosen objectives, giving the most important objective the most points and the least important objectives the least points. Using

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whole numbers, move points among the objectives until the values correctly represent the relative importance of the objectives.  Looking at Table 9.1, the grazing management objectives from the previous example have been ranked according to their relative importance. Notice that the sum of all of the rankings equals 10.  Table 9.2 gives an indexed value that represents the relative likelihood that a particular grazing system will achieve each management objective.  Using the relative value rankings of the objectives in Table 9.1 and the relative likelihood indexes in Table 9.2, the grazing system most likely to meet the defined management objectives can now be determined.  Following the example in Table 9.3, the relative value rankings for each of the objectives found in Table 9.1 is multiplied by the relative likelihood index for each grazing system found in Table 9.2 to arrive with a weighted likelihood index value for each objective and each grazing system.  The weighted likelihood index values for each management objective are then summed across all objectives for each grazing system.  The sum of these weighted likelihood index values indicates which grazing system is most likely to accomplish a given set of objectives.  Weighted likelihood index values do not indicate whether a particular system is good or bad, just which one has the highest likelihood of achieving the desired goals.  In the example, the rest rotational grazing system has the highest weighted likelihood index value, and therefore, has the highest likelihood of achieving the managers grazing management objectives and goals.  Table 9.4 is a blank template to calculate the weighted likelihood index for personal grazing management objectives.

References Reece, P., J. Volesky, and W. Schacht. 2001. Integrating management objectives and grazing strategies on semi-arid rangeland. University of Nebraska Cooperative Extension Service. University of Nebraska. Lincoln, NE. EC01-158.

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Table 9.1. Example relative value ranking of selected grazing management objectives.

Objective 1 Objective 2 Objective 3 Objective 4

Management objectives Maintain current levels of livestock production Improve vegetation cover for wildlife habitat Improve vegetation diversity to increase numbers of grassland bird species Keep investments to a minimum Total

Relative value ranking 4 3 2 1 10

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Management objectives Low

Minimize

Low

Low

Improve

Heal

Optimize

Uniform &

Habitat for

Maximize

financial

management

labor

management

Management

vegetation

sacrifice

yield &

wildlife

ADG

investment

risk

requirements

input

flexibility

diversity

areas

quality

complete forage use

2

10

10

9

10

8

1

1

1

5

5

Management intensive

6

8

3

2

2

1

10

10

10

8

9

Short duration Flash rotation Strip rotation

1 x x

10 10 10

1 1 1

1 3 3

1 1 1

1 1 1

8 8 8

9 9 9

9 9 9

10 10 10

10 10 10

Deferred rotation

8

5

8

4

7

9

5

8

9

6

6

Rest rotation

10

4

8

5

7

9

5

8

9

6

6

Early intensive stocking

1

10

9

3

5

8

1

7

5

10

7

Set-time rotation

6

6

8

5

5

9

1

7

5

6

6

Grazing System Season-long continuous

Table 9.2. Relative likelihood indexes of each grazing system to achieve each grazing management objective (Adapted from Reece et al., 2001).

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Table 9.3. Example weighted likelihood index values of different grazing systems to achieve management objectives.

Management objectives Easy livestock management Grazing Systems Season-long continuous Management intensive Short duration Flash rotation Strip rotation

Wildlife habitat

Table 9.1 x Table 9.2 = Total

Improve vegetation diversity

Table 9.1 x Table 9.2 = Total

Total weighted likelihood

Low financial investment

Table 9.1 x Table 9.2 = Total

Table 9.1 x Table 9.2 = Total

SUM

4

10

40

3

2

6

2

1

2

1

10

10

58

4

2

8

3

6

18

2

10

20

1

3

3

49

4 4 4

1 1 1

4 4 4

3

1 x x

3

2 2 2

9 9 9

18 18 18

1 1 1

1 1 1

1 1 1

26 23 23

Deferred rotation

4

7

28

3

8

24

2

8

16

1

8

8

76

Rest rotation

4

7

28

3

10

30

2

8

16

1

8

8

82

Early intensive stocking Set-time rotation

4

5

20

3

1

3

2

7

14

1

9

9

46

4

5

20

3

6

18

2

7

14

1

8

8

60

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Table 9.4. Weighted likelihood index of different grazing systems to achieve management objectives template.

Management objectives Total weighted likelihood Grazing Systems

Table 9.1 x Table 9.2 =Total

Table 9.1 x Table 9.2 = Total

Table 9.1 x Table 9.2 = Total

Table 9.1 x Table 9.2 = Total

SUM

Season-long continuous Management intensive Short duration Flash rotation Strip rotation Deferred rotation Rest rotation Early intensive stocking Set-time rotation

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Chapter 10 Grazing Distribution Improving grazing distribution in pastures and on rangeland can provide increased utilization of the forage resource and animal performance. Managing proper grazing distribution is just one aspect of an overall grazing management plan.

Grazing distribution factors  Factors that affect grazing distribution include (Schacht et al., 1996): 1) grazing habits of kind and class of livestock, 2) placement of water developments 3) salt and mineral placement 4) palatability of forage 5) vegetation type 6) roughness of topography 7) location of shade 8) fencing patterns 9) pasture size and shape 10) grazing system 11) stocking density 12) prevailing winds Convenience areas  Ideal grazing distribution of livestock occurs when proper utilization extends uniformly over the entire pasture. Livestock generally prefer to expend the least amount of energy possible and therefore are predictable in their grazing behavior.  Convenience areas are areas with in a pasture or management unit that because of their proximity to water, level terrain, and/or high quality forage, are preferred by grazing livestock. Given the freedom of choice and/or the lack of sufficient enticement, livestock will overuse these convenience areas (Figure 10.1).  When stocking rates are applied to a management unit, it is assumed that livestock are evenly distributed across the pasture. However, when this does not occur, convenience areas become overgrazed and less convenient areas are undergrazed.

The result is the delineation of high range condition areas and low range condition areas. Poor grazing distribution in pastures is intensified by placing salt, mineral, and rubs near the water supply.

Results of poor grazing distribution 1. low harvest efficiency because a portion of the pasture is underutilized;

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2. lowered range condition in localized heavily used areas; 3. development of erosion problems in heavily used areas 4. lower animal production (per acre) because of reduced harvest efficiency. ď&#x192;ź Making proper management decisions can improve grazing distribution and increase both forage use and livestock performance.

Figure 10.1. Cattle overusing a convenience area. Photo: Eric Mousel.

Methods for Improving Livestock Distribution ď&#x192;ź Methods to improve livestock distribution can be classified into the following four general categories (Table 10.1). Management decisions can be made to implement the distribution tool.

Table 10.1. Approaches to improving livestock grazing distribution and tools that can help implement the approach (Schacht et al. 1996).

Approach

Tool

1. Enticing animals to specific locations

a. Water development placement b. Salt and mineral placement c. Supplemental feeding location d. Rub and oiler placement

2. Force distribution of grazing animals

a. Fence along range sites b. Pasture size c. Pasture shape

3. Grazing management strategies

a. Rotational grazing b. Stocking density c. Flash grazing

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d. Season of grazing 1. Enticing the grazing animal to forage. Manipulating livestock requirements is an effective tool to draw animals away from preferred areas to less convenient areas.

Water ď&#x192;ź Placement of water is probably the most important single factor affecting grazing distribution (Figure 10.2). Water requirements of grazing animals must be considered when planning water developments. ď&#x192;ź Forage utilization decreases rapidly as the distance to water increases, even in level pastures. Animals will overuse sites near water locations rather than walk greater distances to abundant forage. Consequently, improved animal performance as a result of more efficient use of forage likely will justify the expense of water development on poorly watered pastures.

Figure 10.2. Water location is an important factor affecting distribution of grazing. Photo: Eric Mousel. ď&#x192;ź Topography will affect the spacing of water sources with travel distance varying from 3/4 to 1 mile on level terrain to 1/4 to 1/2 mile on rough terrain. Therefore, a water source on South Dakota pastures and rangelands should be placed every section to one per quarter section.

Where forage production is high, cattle have a tendency to remain closer to water, and forage utilization declines substantially at 800 to 1,000 feet from water. Closer water developments may be justified for highly productive pastureland in the eastern part of the state.

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 Sacrifice areas around water sources will undoubtedly occur. However, the size of the sacrifice area can be kept to a minimum with proper management. Natural water supplies such as lakes, ponds, streams, and springs, and man-made developments such as wells, reservoirs, and dugouts, should be fenced to control loafing around water sources. Quality of the water must not be overlooked. Measures taken to prevent excessive fouling of water sources along with periodic cleaning of tanks should result in increased acceptability and use of water sources.  Periodically changing the accessibility of water locations can be used as a tool to improve distribution in a large pasture. Using wells in conjunction with temporary watering locations (dugouts) can help distribute livestock.

Salt and Mineral  Contrary to popular belief, livestock do not require water following normal consumption of salt and mineral. Therefore, salt and mineral tubs should be placed away from water sources to distribute livestock into seldom used areas.  Salting locations should be more than 1/4 mile from the water and several scattered locations can be used in one pasture. Salt should be moved periodically when forage plants in the area have been properly utilized.

Salt placement is potentially the most economical grazing distribution practice.

Supplemental feeding  When feeding supplemental hay or protein sources in winter, rotating feeding areas among seldom used areas can improve utilization of winter pasture.

Rubs and oilers  Rubs and oilers may be used to attract livestock to lightly grazed areas (Figure 10.3). If efficient use of rubs and oilers does not occur, forced use at access points to water facilities may be necessary. The primary use of these tools is insect control, and their effectiveness should not be compromised.  Adequate fly control has shown positive benefits to good grazing distribution. If flies become a problem, livestock spend more time fighting flies than grazing.

2. Pasture characteristics forcing improved livestock distribution. Physical layout of a pasture, particularly as it relates to fencing, affects distribution of grazing livestock.

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Figure 10.3. Rubs and oilers can be used as tools to improve grazing distribution. Photo: Eric Mousel.

Fencing along range sites or other boundaries ď&#x192;ź Poor utilization in pastures is common because of variability in topography, differences in vegetation, distribution of shelter or shade, and time of plant growth. In pastures with rougher topography, livestock will not use areas that are difficult to get to as they tend to overutilize flat areas that are adjacent to water and generally have lush vegetation and underutilize upland range that is further from water and has a variety of different plant communities. The effects of poor distribution of grazing livestock on pasture utilization and animal performance can be minimized by basing fence placement on such land attributes as range site. ď&#x192;ź Forcing livestock to use inconvenient areas with fences can improve livestock distribution and increase harvest efficiency. Management strategies (e.g., timing and length of grazing periods) are much more effective in a pasture dominated by a single range site than in pastures composed of several sites. Pastures that are fenced by range site can then be incorporated into a rotational grazing system.

Pasture size ď&#x192;ź Pasture size cannot be separated from the effect of distance to water on livestock distribution. The area of a pasture should not result in distances from water that are greater than what livestock will readily use. Generally, livestock distribution can be significantly improved by simply reducing pasture size.

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Pasture shape  Livestock distribution generally is better in pastures that are roughly square, which minimizes distance to water. Long, narrow pastures with water at one end should be avoided because they are typically grazed much more heavily near the water source and are underutilized away at the other end. As pastures become longer and narrower, overuse will increase close to the water source. Shape is much less critical for smaller pastures where livestock are never more than 1/4 mile from water.

3. Grazing management strategies that influence livestock distribution Rotational grazing  Rotational grazing involves moving livestock through two or more pastures with each pasture grazed one or more times during the growing season.  Rotational grazing can be used to affect grazing distribution within a pasture because multiple, smaller paddocks can decrease distance to water and increase stocking density (number of animals per unit area at any point in time) while making pasture size and shape more uniform.

Stocking density  Rotational grazing increases stocking density in individual pastures because, livestock are no longer spread over one large pasture but consolidated into a subunit of the entire grazing area. As the number of animals in a pasture increases the amount of forage available to each animal decreases. Therefore, increasing stocking density frequently improves grazing distribution and harvest efficiency because of competition between animals for limited forage.  With heavy grazing pressure and rapid removal of forage, a greater portion of the pasture forage is consumed by livestock and less is lost to such things as trampling, spoilage by animal wastes, and plant maturation and leaf death. As stocking density increases, livestock performance (e.g., daily gain) should be monitored closely. Individual animal performance typically declines as stocking density increases.

Season of grazing  There are a number of environmental factors, plant characteristics, and animal requirements that change through the year and affect livestock grazing distribution.

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 Decisions concerning grazing schedules should take into account seasonal changes in plant acceptability and livestock grazing behavior. Many plants that are unpalatable at maturity are acceptable to grazing livestock in immature stages. Pastures dominated by plants with seasonal shifts in palatability should be grazed when utilization and distribution are optimum.  Grazing distribution of cows will generally improve during the late fall and winter because of decreased water needs and lower nutrient requirements after weaning. Utilization across a pasture also will be affected by environmental factors such as frost. Frost tends to reduce the coarseness of some forage plants and improve their utilization.

References Schacht, W.H., J.D. Volesky, and S.S. Waller. Proper livestock grazing distribution on rangeland. University of Nebraska Cooperative Extension Service. University of Nebraska – Lincoln. Lincoln, NE. G80-504-A. Horn, B.E. 2005. Livestock grazing distribution. University of Wyoming Cooperative Extension Service. University of Wyoming. Laramie, WY. MP-111.05.

Waller, S.S., J.T. Nichols, and J.P. Buk. 1980. Proper livestock grazing distribution.

University of Nebraska Cooperative Extension Service. University of Nebraska – Lincoln. Lincoln, NE. Ohlenbusch, P.D. and J.P. Harner III. 2003. Grazing Distribution. Kansas State University Cooperative Extension Service. Kansas State University. Manhattan, KS. MF-515.

Chapter 11 Pasture Monitoring

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Pasture monitoring is the orderly collection, analysis, and interpretation of resource data to evaluate progress towards meeting management objectives. Monitoring forage response to grazing is an essential feature of any grazing management plan. It provides measurable data that will allow determination of the effect a grazing management plan is having on the forage resource. Without a pasture monitoring program, managers are unable to evaluate the effects of a management plan and are unable to adjust the plan if forage species are not responding towards the management objectives. Monitoring activities also should be set-up to evaluate condition of pastures and rangeland over the short- and long-term.  Monitoring should occur in areas of the pasture that are representative of the total use of the pasture and should reflect the overall acceptability of the current management strategy over the entire pasture.  Areas near water sources, stream crossings, fence lines, and mineral tubs are generally not good monitoring points because of they are areas where livestock habitually congregate.  It is preferable to have at least one monitoring point in every pasture; however, it is also important to limit the number of monitoring areas so that they can be evaluated in a consistent and timely manner.  Monitoring programs should take place at the same time each year and should be repeated at regular time intervals. Generally, both short- and long-term monitoring points should be evaluated between May and October depending on the type of vegetation and its location.  Short-term monitoring points should be evaluated at least once or more per growing season. Long-term points should be monitored every 2 to 5 years.  Monitoring points should be evaluated either before or after the grazing period with follow-up monitoring activities being conducted under similar conditions.

Short-term monitoring Short-term monitoring allows managers to determine the current effect of their management strategy on the forage resource. Conducting a monitoring program midseason allows for evaluation of whether or not the grazing system is meeting the management objectives for the operation and adjustments to the grazing program if necessary. Several methods of short-term monitoring are available to evaluate grazing programs; however, the three simplest monitoring activities that will provide excellent data for evaluation are: 1) measuring stubble height of key forage species, 2) forage utilization mapping, and 3) using a pasture use index.

Stubble height

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Measuring stubble heights of key forage species following grazing allows managers to evaluate the intensity of grazing that has occurred during the previous grazing period. Here are some key points to remember when measuring stubble heights:  When measuring stubble heights of key forage species it is important to remember to use the average stubble height of species over a representative area or areas. A few measurements in an unrepresentative area (e.g. near a watering source) can give a very skewed look at what effect the grazing program is really having on the forage resource.  Appropriate stubble heights for selected key forage species following a grazing period are listed in Table 11.1.  Stubble heights are only useful for short-term evaluation of grazing intensity, they give no indications as to what long-term effects a management system is having on the forage resource.  Stubble heights are an excellent method of monitoring forage use in improved pastures in the eastern one-third of the state. In the western two-thirds of the state, care must be taken when using stubble heights to evaluate key forage species.

Stubble heights as numeric values on western rangelands should be used in combination with measurements of utilization and a pasture use index to evaluate short-term grazing management effects on the forage resource.

Forage Utilization Mapping Utilization is defined as the proportion of the current year’s forage yield that is consumed or trampled and wasted by grazing livestock. Distribution of grazing livestock and consequently, forage utilization can vary significantly within a pasture. Factors such as topography and distance to water can cause some areas of a pasture to be over-grazed while other areas are under-grazed. Generating maps that identify over-used and underused areas with in a pasture can allow the manager to make critical management decisions based on pasture use.  Forage utilization can be measured in a variety of ways, but measuring residual stubble heights of key forage species and the use of grazing exclosures are the easiest and most effective tools.  Table 11.1 indicates the stubble heights of different key forage species when approximately 50% utilization has occurred.  Stubble heights greatly in excess of those in Table 11.1 suggest under-grazing of key forage species. Stubble heights of key forage species that are less than those suggested in Table 11.1 may indicate over-grazing of those species.

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 Grazing exclosures allow for the comparison of current forage use to the current year’s forage production for that site (Figure 11.1).  After taking stubble height measurements of grazed key forage species outside of the exclosure to heights of ungrazed plants within the exclosure, you can then calculate utilization of forage by grazing livestock by using the following equation:  current utilization (%) = inside stubble height – outside stubble height inside stubble height

Figure 11.1. The use of a grazing exclosure to assess forage utilization. Photo: Eric Mousel.

Pasture use index Pasture use index systems are tools used to evaluate the integrated effects of multiple environmental and management variables on the forage resource. An index system attaches numerical values to different levels of management and environmental factors to create a summative index score from which management decisions next year can be made (Reece et al., 2003).

By indexing the interactions between grazing date, precipitation, remaining stubble height, and fertilization, you can come up with a relative index score that can be used as a proxy to evaluate the need for management adjustments.

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Using the Pasture Use Index Grazing Date  Record the index value that corresponds with the month the pasture was grazed. If grazing covers more than one month, add the index values of those months together (Tables 11.2 and 11.3).

Precipitation  Record the index value that corresponds with the precipitation levels that occurred through the calendar year.

Pasture Stubble Height  Record the index value that corresponds with the average stubble height of key forage species after the final grazing period.

Fertilization (Table 11.3 only)  Record the index value that corresponds with whether the pasture was fertilized in the current year or not.

Calculating the Index Score  Add up the index values from each of the 3 or 4 categories to get a pasture score.

Pasture scores can range from -9 to +10.

Management Adjustments  The objective is to avoid negative pasture scores.  (-) If pasture score is negative, the time that the pasture is grazed next year should be changed. If pasture score is negative two years in a row, the time that the pasture is grazed next year should be changed and stocking rate should be reduced to aid recovery.  If pasture score is zero, the time that the pasture is grazed next year should be changed but no stocking rate adjustments will likely be necessary.  (+) If pasture score is positive, the time that the pasture is grazed next year should be changed however, management practices are sufficient to sustain long-term forage production and animal performance.

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Table 11.2. Pasture use index for western wheatgrass-green needlegrass dominated rangeland (Modified from Reece et al., 2003).

Grazing Date April: spring green-up May: early rapid growth June: late rapid growth July: seed set August: summer dormancy Fall: September â&#x20AC;&#x201C; October (new tiller initiation) Winter: November â&#x20AC;&#x201C; March (true dormancy)

Index 0 -1 -3 0 1 -1 +3

Precipitation (April through June) Well above average (greater than 25% above normal)

Index 2

Near normal

0

Drought (less than 75% of normal)

-2

Stubble Height (of key forage species) Key forage species

Index

Excellent: 4 to 8 inches of stubble

+2

Adequate: 2 to 4 inches of stubble

0

Poor: Less than 2 inches of stubble

-2

Table 11.3. Pasture use index for smooth bromegrass dominated pastures (Modified from Reece et al., 2003).

Grazing Date April: spring greenup May: early rapid growth phase June: late rapid growth phase July: seed set August: summer dormancy Multiple events during May - October Fall: September - October (new tiller initiation for next year)

Index 0 -3 -2 1 2 -3

Precipitation Well above average (grater than 25% above normal)

Index 2

-2

Near normal

0

Drought (Less than 75% of normal)

-2

Stubble height (of key forage species) Excellent: Greater than 8 inches of stubble

Index 2

Adequate: 4 to 8 inches of stubble

0

Poor: Less than 4 inches of stubble

-2

Fertilization Fertilized

Index 2

Not fertilized

0

Long-term monitoring Long-term monitoring allows for the evaluation of changes in the condition of pastures or rangelands as a result of your management program. Assessments of increasing or decreasing amounts of key forage species, invasive species, litter, and bare ground are useful in determining whether condition of pastures are improving or degrading. Using combinations of photo points and grazing exclosures are excellent methods of monitoring long-term changes in range condition.

Photo points  Identifying and permanently marking points throughout a pasture and taking an annual photo is an effective way to monitor management effects on rangeland and pasture.  Photos can be an up-close of a specific plot in a pasture or a landscape photo that includes a landmark so the photo can be repeated annually (Figure 11.2).  Using plot frames to mark up-close photo points can be easily achieved by making a 3’ x 3’ frame out of PVC and driving stakes into the ground so you can put the frame in the same place every year (Figure 11.3).

Figure 11.2. Landscape view of pasture use at a photo point. Photo: Eric Mousel.

Figure 11.3. Use of a permanently marked plot frame at a photo point. Photo: Eric Mousel.

References Bruhjell, D. 2005. Monitoring grazing lands. British Columbia Ministry of Agriculture, Food, and Fisheries. Kamloops, BC, CA. Grazing Management Factsheet No. 7.

Reece, P.E., J.D. Volesky, and W.H. Schacht. 2003. Sandhills defoliation response index system: A decision support tool for optimizing grazing management.

Taylor, J.E. and J. Lacey. 1987. Monitoring Montana Rangelands. Montana State University Cooperative Extension Service. Montana State University. Billings, MT. Ext. Bull. 369.

108 Chapter 12 Managing Wildlife Habitat with Grazing Management There is no universal grazing approach that will benefit all wildlife species. Some species are most abundant under heavy grazing while others may thrive under moderate, light, or ungrazed conditions. Livestock affect wildlife habitat directly by removal and/or trampling of vegetation that could otherwise be used for food and cover. Such effects can also benefit wildlife populations by opening dense stands of herbaceous or shrubby vegetation that retard wildlife movement. Since most land in South Dakota is used primarily as a forage source for beef cattle, management can have a tremendous impact on the type and amount of habitat available for use by wildlife. Management practices that sustain relatively high levels of livestock production may be favorable for deer and some species of song birds. However, without high quality cover, populations of upland game birds like sharp-tailed grouse, prairie chickens, and ring-necked pheasants will be limited.  High quality cover provides complete visual obstruction of birds and nesting sites at relatively close distances. Production of high quality cover for game birds throughout a pasture will require the manager to allow accumulation of at least some residual herbage over the growing season by limiting haying and grazing activities. Some residual herbage from the preceding year generally must be combined with current year’s growth to produce high quality cover.  Because South Dakota rangelands are dominated by grasses, grazing and haying decisions on ranches and other management areas will determine the amount of high quality cover that is available for nesting, brooding and loafing each year.

Maximizing livestock production and upland game bird habitat at the same time is difficult, if not impossible. However, optimum production of both livestock and wildlife habitat is achievable through proper management.  Decisions must be made by the manager as to the relative value of wildlife to the operation and determine if the losses in grazing and haying can be recouped through the value of the wildlife habitat produced.  When developing habitat management plans, topographic features such as ridges and draws, thickets of trees and shrubs, location of riparian areas, cropland, and existing high quality cover must be considered to optimize habitat availability for wildlife.  Developing high quality cover in several areas that provide safe corridors of movement between feeding, loafing, and watering areas is often better than a single, large block of cover for quail and pheasants.  Pheasants benefit from a relatively diverse land use that provides a mosaic of 40to 160-acre cover and food resource areas. Very large blocks of grassland are

109 needed to sustain grouse populations where only two to six successful nests per section may occur even with an abundance of high quality cover.  Understanding the annual reproductive cycle of wildlife species is critical for successfully meeting habitat requirements.  For upland game birds and waterfowl, timing and quality of cover are critical as high quality nesting cover must be available at different times during the early spring through mid-summer months (Figure 12.1).  Nesting generally occurs from late March through late July. Young birds will stay with hens for 36 to 84 days. On average bluewinged teal hens will brood chicks for 38 days while brooding time for mallards, grouse, and pheasants will last about 70 days.  Wildlife populations fluctuate cyclically in response to consecutive years of above or below average habitat conditions. Implementing good habitat management practices can maintain higher populations during low cycles and support rapid population growth when favorable conditions return.  Cold wet weather during the hatching period and hot dry weather during the brooding period will limit populations of upland game birds and migratory waterfowl.  Young birds are susceptible to high soil surface temperatures during the summer months in the absence of adequate cover, especially during drought years as air temperatures generally are above average and vegetation cover is reduced over large areas in response to limited soil moisture.

The relative benefit of managing an area for habitat will depend on how well the landscape provides food, water, and cover over the entire year. Habitat requirements should be within average travel distances for the age of selected wildlife species.  Resource areas for young birds should be relatively close in proximity to one another to limit distance of travel. Pheasants are heavy bodied birds with relatively short flight distances often less than ¼ mile.  Mature grouse will commonly travel 2 miles or more between resource areas.  Scattered weed patches, food plots, and cropping systems can benefit many bird species. Key food plant species must be in sufficient number within the plant community to provide an adequate food supply. Row crops and alfalfa generally provide poor nesting sites because cover is limited in the spring and fields are cultivated or harvested during the spring and summer.

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Figure 12.1. Distribution of hatching activities in populations of sharp-tailed grouse, bluewinged teal, mallards, and pheasants (Reece and McDaniel 1998).  However, birds will use these areas for brooding and loafing if they are in close proximity to other sources of high quality cover.

Increasing the amount of edge effect habitat generally increases wildlife populations because most species require several vegetation types to meet their needs.

The edge effect simply describes where two habitat types come together. Roadsides, ditch banks, fence lines, shelter belts, and farmsteads are a few examples of edge effect habitat.  These areas provide the greatest opportunity for nesting cover because residual herbage from preceding years is allowed to accumulate. These areas also provide high quality cover at all times of the year, which is critical to sustaining high populations of upland game birds.  In contrast, cover requirements for ducks are seasonal because they generally migrate in the fall and return in the spring.  When carefully controlled, grazing can be a useful tool for the enhancement of wildlife habitat.

111  Stocking rate is the primary driver of the amount of residual herbage available for use by wildlife as high quality cover. Consequently, the ability of wildlife to carry out daily and seasonal activities without being observed by predators declines as stocking rate increases.  Maintaining adequate amounts of residual herbage for high quality cover during nesting and brooding periods is a key grazing management objective for increasing habitat for wildlife (Figures 12.2 and 12.3).  Rest rotation and deferred rotation grazing systems are beneficial to most upland bird species because they allow the manager to provide pastures free from disturbance during the nesting and other critical seasons.

Figure 12.2. Adequate residual vegetation following early-summer grazing to provide high quality habitat for nesting, brooding, and winter cover. Photo: Sandy Smart.  Deferred rotations also can allow for the optimization of concurrent livestock production as vegetation accumulated in deferred pastures can be used by livestock after critical wildlife reproductive periods (Figure 12.2). Careful attention must be paid to stocking rate use in these systems as the benefit of additional residual herbage to wildlife could be offset by heavy grazing by livestock in non-deferred pastures if stocking rates are set too high.  Uncontrolled livestock grazing has been shown to be quite detrimental to waterfowl species. However, the use of grazing systems, which allow the manager to control grazing activities of livestock, have the potential to

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Figure 12.3. Poor residual vegetation following summer grazing. This situation provides very little habitat for nesting, brooding, and winter cover. Photo: Sandy Smart. enhance waterfowl habitat and optimize livestock production when appropriately applied. ď&#x192;ź Water fowl prefer a mosaic of cover and open water to conduct their critical activities. Tall robust plants in extensive, unbroken stands often dominate areas around stock ponds, lakes, and drainage streams. ď&#x192;ź Excessive accumulation of vegetation can be detrimental to movement and use of these areas by waterfowl for nesting and brooding. Using controlled grazing can help improve waterfowl habitat by periodically disturbing the vegetation in these areas and increasing the utility of cover available, particularly if grazing is delayed until after June.

Grazing Management to Increase Cover Habitat for Ring-Necked Pheasants The relative benefit of managing an area for pheasant habitat will depend on how well the landscape provides food, water, and cover over the entire year (Figure 12.4). Habitat requirements should be within average travel distances for the age of selected wildlife species. Resource areas for young birds should be relatively close in proximity to one another to limit distance of travel.

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Figure 12.4. Management strategies should be based on providing each component required by the pheasant to maintain adequate reproduction and winter survival.

Food  Nearly 80 percent of an adult pheasant’s diet is composed of cereal grains like corn, wheat, oats and barley (Trautman 1982). These grains are usually provided by waste following crop harvest.  The remaining 20 percent of the diet is a combination of insects and weed seeds.

Insects are a substantial component of the diet in the spring and early-summer, but declines through the summer and into the fall (NGPC 1989).  Weeds seeds can account for 5 to 15 percent of the diet while green plant leaves make up about 20 percent of the diet in May but declines through the summer (Knight 1995).  In the winter, fruits from woody vegetation such as buck brush, wild rose, and Russian olives (Johnson and Larson 1999).

Nesting Cover  Understanding the annual reproductive cycle of the pheasant is critical for successfully meeting habitat requirements.

114  Pheasants are highly dependent on agricultural management practices to meet their survival requirements however, quality cover is usually the most limiting factor on lands used for agricultural production.  High quality cover provides complete visual obstruction of birds and nesting sites at relatively close distances.  Production of high quality cover for birds throughout a pasture will require the manager to allow accumulation of at least some residual herbage over the growing season by limiting haying and grazing activities.  Some residual herbage from the preceding year generally must be combined with current year’s growth to produce high quality cover.  Timing and quality of cover are critical as high quality nesting cover must be available during the peak nesting period from April through late-July (Trautman 1982).  Wetlands, unmowed road ditches, and small cereal grains will provide adequate nesting cover.  Pheasants often try to use alfalfa for nesting cover. Although alfalfa is an important component of pheasant habitat, it makes poor nesting cover because many nests are destroyed during alfalfa harvest.

Brooding Cover  Habitat needed for brooding by pheasants must include a significant broadleaf plant component such as annual and perennial forbs and weeds or alfalfa to provide an abundance of insects.  Insects are the major food source for pheasant chicks during their first three weeks following hatch (Trautman 1982).  Lush, tender plant leaves become a progressively more important food source for chicks after the first three weeks.  Ideal brooding cover is layered with vegetation of variable heights and densities.

Cover should be thick from ground level to about eight inches high. Vegetation between eight and 20 inches should be fairly dense, becoming thinner at 20 to 40 inches (Knight 1995).  Areas that can generally provide these cover requirements are generally referred to as edge effect habitat. The edge effect simply describes where two habitat or vegetation types come together.

115  Ungrazed or lightly grazed pastures that include some annual and perennial forbs or weeds, roadsides, ditch banks, fence lines, shelter belts, and farmsteads are a few examples of edge effect habitat.  These areas provide the greatest opportunity for nesting and brooding cover because residual herbage from preceding years is allowed to accumulate. These areas also provide high quality cover at all times of the year, which is critical to sustaining high populations of pheasants.

Winter Cover  Winter cover is generally the most limiting component of pheasant habitat. With field vegetation cover mostly eliminated by crop harvest, grazing, and haying, pheasants must rely heavily upon marshlands (sloughs), CRP fields, shelterbelts, and farm groves that are in close proximity to a food source for places to roost, loaf, and for protection against storms and predators (NGPC 1989).  Even with an abundance of wooded areas for pheasants to congregate, understory cover can be limited because of old aged stands or by livestock grazing.  Herbaceous understory in winter cover should be at least 15 inches high to protect birds from snow, bitter cold and high winds (Knight 1995).  Cattails and bulrush in wetlands and along rivers and streams provide pheasants with excellent winter cover. Summer management of these areas is critical to produce the proper vegetation characteristics needed.  Livestock should be excluded from these areas in most situations to prevent extensive trampling and overgrazing of vegetation (Gersib 1991). However, livestock can be used intermittently in mid- to late-summer to break up wetland vegetation that has become too dense to be useful winter cover for pheasants.

Grazing Management  When carefully controlled, grazing can be a useful tool for the enhancement of pheasant habitat. Seasonal stocking rates are the primary driver of the amount of residual herbage available for use by pheasants as high quality cover for nesting and brooding.  Consequently, the ability of pheasants to carry out daily and seasonal activities without being observed by predators declines as stocking rate increases (Reece et al. 2001).  Using a conservative seasonal stocking rate to maintaining adequate amounts of residual herbage for high quality cover during nesting and brooding periods is a key grazing management objective for increasing habitat for pheasants.

116  Having both cool-season and warm-season grass dominated pastures in a complementary forage system can increase the availability of quality cover for pheasants and enhance livestock production.  Big bluestem, indiangrass and switchgrass are warm-season tallgrasses that provide excellent winter cover for pheasants and can be used by livestock after cool-season grasses like smooth bromegrass or western wheatgrass have ceased production during the hot, dry summer months.  Leaving a minimum of 12 to 15 inches of residual stubble in pastures at the end of the grazing season will ensure optimum winter protection and nesting cover the following spring.  Using proper grazing management can give managers the opportunity to successfully maintain adequate residual grass stubble for pheasant cover without significantly reducing livestock production.  Rest rotation and deferred rotation grazing systems are beneficial to most upland bird species because they allow the manager to provide pastures free from disturbance during the nesting and brooding periods (Duff 1979).  Rest-rotation systems require one full calendar year of non-grazing for one pasture in the system (Figure 12.5).  The pasture that is rested is then rotated among the pastures in the system in subsequent years. Deferred rotation systems require one full growing-season of non-grazing for one pasture in the system (Figure 12.6).  Deferred rotations also can allow for the optimization of concurrent livestock production as vegetation accumulated in deferred pastures can be used by livestock after critical pheasant reproductive periods. However, careful attention must be paid to stocking rate use in these systems as the benefit of additional residual herbage to wildlife could be offset by heavy livestock grazing in nondeferred pastures if stocking rates are set too high.

117 Rest Rotation Grazing System

Figure 12.5. Example scenario of a rest rotation grazing system that allows one calendar year of rest for one paddock to provide nesting, brooding, and winter cover for pheasants.

Grazing begins May 1 and ends September 30. Quality cover may be available in other paddocks if grazing time is managed appropriately.

118 Deferred Rotation Grazing System

Figure 12.6. Example scenario of a deferred rotation grazing system that allows one paddock to be deferred from grazing after an initial grazing period in May to provide winter cover and one paddock to be deferred from grazing until September to provide nesting and brooding cover for pheasants. Grazing begins May 1 and ends September 30.

Quality nesting and brooding cover may be available in other paddocks if grazing time is managed appropriately.

119 References Belanger, L., and M. Picard. 1999. Cattle grazing and avian communities of the St. Lawerence River islands. J. Range Management. 39:332-338.

Connelly, J. W., M. W. Gratson, and K. P. Reese. 1998. Sharp-tailed Grouse (Tympanuchus phasianellus). In The Birds of North America, No. 354 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA. Duff, D.A. 1979. Riparian habitat recovery on Big Creek, Rich County, Utah. In: Forumgrazing and riparian stream ecosystems. p. 91-92. Trout Unlimited. Denver, CO. Gersib, R. 1991. Wetlands. In: Wildlife habitat improvement guide. Nebraskaland Magazine. Nebraska Game and Parks Commission. Lincoln, NE. 69:1. p. 54-57.

Giudice, J. H., and J. T. Ratti. 2001. Ring-necked Pheasant (Phasianus colchicus). In The Birds of North America, No. 572 (A. Poole and F. Gill, eds.). The Birds of North America, Inc., Philadelphia, PA. Johnson, J.R. and G.E. Larson. 1999. Grassland Plants of South Dakota and northern Great Plains. South Dakota State University. Brookings, SD. B-566.

Kaiser, P.H., S.S. Berlinger, and L.H. Fredrickson. 1979. Response of blue-winged teal to range management on waterfowl production areas of southeastern South Dakota. J. Range Management. 32:295-299.

Kantrud, H.A. 1990. Effects of vegetation manipulation on breeding waterfowl in prairie wetlands – A literature review. In: Can livestock be used as a tool to enhance wildlife habitat? U.S. Dept. Agric. For. Serv. Gen. Tech. Rep. RM-194.

Knight, J. 1995. Managing Montana farm habitat for pheasants. Montguide. Montana State University Cooperative Extension Service. Montana State University. Billings, MT. MT-9515.

NGPC. 1989. The ring-necked pheasant in Nebraska. Nebraskaland Magazine. Nebraska Game and Parks Commission. Lincoln, NE. Reece, P.E. and L. McDaniel. 1998. Range Judging Handbook and Contest Guide for Nebraska. University of Nebraska Cooperative Extension Service. University of Nebraska – Lincoln. Lincoln, NE. EC98-150-F. Reece, P.E., J.D. Volesky, and W.H. Schacht. 2001. Integrating management objectives and grazing strategies on semi-arid rangelands. University of Nebraska Cooperative Extension Service. University of Nebraska – Lincoln. Lincoln, NE. EC01-158.

120 Trautman, C.G. 1982. History, ecology, and management of the ring-necked pheaseant in South Dakota. South Dakota Department of Game, Fish, and Parks. Pierre, SD.

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