Feeding Signals - English edition by Roodbont Publishers

Feeding signals

This book contains a fascinating array of practical tips and valuable guidelines about the essence of healthy, economical feeding. Did you know that a cow that can’t eat with the group eats her meals faster and takes in less feed overall? That a dairy cow produces about 200 litres (53 US gal.) of saliva a day and pumps about 15,000 litres (4000 US gal.) of blood through her udder? And that most farms prefer not to feed early in the morning? In addition, Feeding Signals shows you what you as a dairy farmer can do today to improve your feed management, with reliable information, short explanations and lots of images taken on working farms.

Feeding Signals is part of the Cow Signals® series. These books present highly practical knowledge on animal-focused dairy farming in an accessible way. ISBN 978-90-8740-156-6

9 789087 401566

Jan Hulsen Dries Aerden Jack Rodenburg

e Fe

Health

Space

Feeding Signals answers the four practical questions that every dairy farmer and worker on every dairy farm asks: 1. What should I feed and how much? 2. What is the best way to make sure every animal gets the right ration? 3. How do I check that every animal is eating what they should be eating? 4. How do I make adjustments and solve particular problems?

The basic needs of the cow can be summarised by seven key words, which form the corners of the Cow Signals Diamond. These seven basic needs are feed-water, light-air, peace-space and health. As a dairy farmer you should always pay close attention to these needs, in order to ensure good health and welfare and optimum milk production. For effective feed management, you will also need to pay special attention to the corners of the Cow Signals Diamond.

Light

Jack Rodenburg advised dairy producers in Canada on feeding and management of their herds for 34 years as an extension specialist with the Ontario Ministry of Agriculture. In this role he did extensive work on ration formulation, feed storage and manger design and on the nutritional impact of water quality. He has worked with the Vetvice team on numerous projects and currently operates DairyLogix, a Canadian consulting firm that focuses on farm application of robotic milking and other precision technologies. He has co-authored two other CowSignals books, on robotic milking and on barn design.

Good feeding is the basis of your farm’s success, not only financially but also in terms of production, animal health and fertility. Did you know that almost 50% of the differences in milk production between farms is determined by the ration composition? And that the rest is down to other things such as housing, animal health and cow management?

Jan Hulsen - Dries Aerden - Jack Rodenburg

Dries Aerden studied at the K.H. Kempen University College in the western Belgian town of Geel. After acquiring international experience at a number of large specialised dairy farms in Denmark and the USA, he joined the Belgian consultancy LIBA. Dries has a strong interest in feed and the impact it can have on the economics of dairy farming. LIBA specialises in the financial side of dairy farming – business accounting and drawing up business plans – and in operational management. It also offers an online application called the Cowdashboard™, which is an easy way for dairy farmers to track their feed balance. LIBA provides advice on how to improve the feed balance and financial management on a dairy farm.

An old Dutch farmers’ saying

The Cow Signals Diamond

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Jan Hulsen grew up on a farm with dairy cows and pigs. He studied veterinary medicine and also has a particular interest in communication. After working as an agricultural vet for three years, he decided to focus on knowledge transfer and consulting and undertook further training in journalism, marketing, communication and business administration. With his company Vetvice, Jan developed the Cow Signals® concept and wrote the successful Cow Signals® series of books. Vetvice gives talks and training sessions on all aspects of Cow Signals® in more than 30 countries. Vetvice’s main speciality is dairy farm management. In addition to animal care, it also focuses on staff welfare and productivity. Vetvice advises and trains livestock farmers on barn design, work organisation and disease prevention.

‘You feed with your eyes’

Feeding signals

About the authors

Feeding signals A practical guide to feeding dairy cows for health and production

www.roodbont.com

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www.vetvice.com

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03-12-13 21:32

Credits

Feeding Signals

For books, digital content and customised editions

Authors Jan Hulsen Dries Aerden Jack Rodenburg Editors Ton van Schie Christel Lubbers Translation Agrolingua English content editors Owen Atkinson Jack Rodenburg

Illustrations Trudy Michels, Studio Michels Herman Roozen Design Varwig Design

For farming and barn construction advice

Vetvice® Group Moerstraatsebaan 115 4614 PC Bergen op Zoom The Netherlands T +31 165 30 43 05 E info@vetvice.nl I www.vetvice.nl

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Photography Jan Hulsen (unless otherwise stated) Anneke Hallebeek (31) Broer Hulsen 7, 9 (2x), 31 (2x), 50, 78) Bertjan Westerlaan (28)

Roodbont Publishers B.V. Postbus 4103 7200 BC Zutphen The Netherlands T +31 575 54 56 88 E info@roodbont.com I www.roodbont.com

With the collaboration of Joep Driessen, Dick de Lange, Bert van Niejenhuis, Pieter Paschyn, Nico Vreeburg, Bertjan Westerlaan, Jaap van Zwieten

Special thanks to Owen Atkinson, Jack Rodenburg, Freek van Essen, Kees Haanstra, Paul Hulsen, René Knook, Roel Koolen, Adri Maas, Aart Malestein, Niek Mangelaars, Ria en Ronald Raats, Kees Simons, Lucas Talsma and a great many livestock farmers, advisors, vets and others involved with dairy cows and dairy farming

Feeding Signals is part of the successful Cow Signals® series. Koesignalen® and CowSignals® are registered trademarks of Vetvice®. © Jan Hulsen, 2014

Vetvice provides dairy farmers and their advisors and suppliers with practical and reliable information on cattle farming that has been acquired through scientific research and practice. By doing so we are endeavouring to achieve maximum welfare and health for animal and man in an economically profitable production system that delivers top quality foodstuffs.

For training sessions, workshops and presentations

CowSignals® Training Company Hoekgraaf 17A 6617 AX Bergharen The Netherlands T +31 6 54 26 73 53 E info@cowsignals.com I www.cowsignals.com

No part of this publication may be duplicated, photocopied, reprinted or reproduced in any form without prior written permission from the publishers. The authors and publishers have made every effort to ensure the accuracy and completeness of information contained in this book. However, the authors and publishers assume no liability for damage of any kind resulting from actions and/or decisions based on this information. The publisher has made efforts to trace the owners of the visual material. Where a source is uncredited, the owners can contact the publisher. ISBN: 978-90-8740-156-6

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LIBA Dorpsstraat 21 3950 Bocholt Belgium T +32 (0)89 46 46 06 F +32 (0)89 46 11 79 E info@liba.be I www.liba.be Feeding Signals

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Contents

Introduction: Behavioural needs and feeding behaviour Behavioural needs

Feed and digestion in the cow

Rumen function: mixing, passage

4: Measuring and managing via the cow

Identifying and reducing sorting

Rumen fill

Addressing problems; making improvements

Manure consistency scorecard

Digestion of feedstuffs

Feed intake, milk production and rumen pH

Energy and protein drive fermentation Rumen pH

Assessing individual feed intake Rumen fill and function Assessing manure

Feed digestion scorecard

Manure sieving instruction card

1: Eating

Optimal eating

Scheme assessing sieved manure

Water intake

Eating in comfort

5: Measuring and managing as manager

Targeting economy: income over feed cost

Targeting milk production

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Plenty of time to eat Space, rest and peace

Measuring and analysing

Heat stress

Targeting feed conversion efficiency

Walking and lying in comfort Grazing

2: Storage, loading and feeding Optimal feeding

Loading, mixing, feeding

Loading the feed mixer wagon

Measuring = knowing what is really happening Monitoring and calibration The manger

Using the forage separator Ensiling

Optimal grazing

3: Ration calculation Rumen fermentation rate Fibre

Assessing the forage analysis Assessing forage

Forage inventory

Managing forage inventory

Successful dry period and transition

24 25

Ketosis and fatty liver

6: Feeding-related cow problems

Abnormal behaviour and feeding

Milk fever

36 37

70 71

Too much acid production in the rumen

Managing BCS

Foot problems

Hardware disease

Abomasal displacement to the left or the right Nutrition status, production and fertility Minerals: too little or too much

Index 79

40 42 43

Forage analysis: explanation of terms

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Contents

TMR: Total Mixed Ration

PMR: Partial Mixed Ration

Dry period

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Introduction

Behavioural needs and feeding behaviour Cows are social, grazing, ruminating prey animals. It is rumination that sets cows apart from other animals: thanks to the fermentation processes in the rumen, cows can turn low quality forage into high quality food – milk and meat. Tailoring your feeding, housing and care to the needs and attributes of the cow and her digestive system enables you to optimise production, health and welfare.

co pr py ot rig ec h te t d

And that leads to sustainability and a good income.

Social behaviour and eating together

Cows eat, lie and walk together in groups. Stress and food aggression occur if not all the animals in a group can eat at the same time. An animal that can’t eat or lie at the same time as the rest of the group will eat her meals faster and will eat less. Cattle use eating to confi rm group relationships and dominance. This is usually demonstrated with very short, rapid signals. Dominant cows make it clear that they are the boss and low-ranking cows indicate that they know their place. This also happens at drinking places. It is essential for the animals.

Grazing cows fill their rumens with grass and then go and lie down in a dry, safe place to chew their cud. They do everything in groups, and all the animals in a group eat and rest at the same time.

Rumen flora make the menu

Vegetable material contains a lot of cellulose. Animals can’t digest this, but microorganisms such as bacteria can. Ruminants have two stomachs in which microorganisms break up the feed they have eaten. This process is called fermentation, the stomachs are called the rumen and reticulum, and all the microorganisms are collectively known as the rumen fl ora.

Sufficient chewing

A high-producing lactating cow eats for 14 to 16 hours a day on average. On an indoor ration she chews for 4 to 6 hours and ruminates for 9 to 11 hours. With 100% grazing it is roughly the other way round. 4

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Suffi cient chewing and, in particular, chewing the cud are a sign of a healthy ration that contains the right amount of fi bre. Chewing well keeps the rumen healthy and encourages plenty of ruminal activity, which is also necessary for a healthy rumen. Feed containing too little fi bre gives rise to abnormal behaviour among calves, such as udder sucking, navel sucking and urine drinking, and forms hairballs in the rumen. With older cows this can lead to rumen problems, gastric ulcers, intestinal problems, pica (eating things they shouldn’t) and diarrhoea.

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Behavioural needs

Cows need rest and peace

Prey animals always keep an eye on each other and their surroundings and react immediately to any threats, other animals’ reactions and unfamiliar situations. A nervous cow eats more quickly. But this also means that she eats less. And she stays standing up instead of lying down. In a relaxed herd all the cows eat at ease, but this is not the case in a nervous herd. Calm is created by giving the cows a sense of safety and certainty. Nervousness can quite easily be prevented if every cow can react safely. Nervousness can be caused by many things, such as confl icts with other cows, fear of people or equipment, and unexpected, frightening events. Not being able to lie down enough also causes a lot of nervousness and stress – this happens when there are not enough lying places, or when the lying places are not comfortable.

Walking is healthy

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Cows don’t have an overwhelming desire to walk around, but walking is very benefi cial to their vitality. If they have enough space to walk in, they will also have enough personal space, room to avoid confl icts and room to escape. In their natural environment cows walk from 5 to 15km (3 to 9 miles) a day, depending on the amount of grass and the distance to water. In a cubicle house, a dairy cow not in heat walks 1.5 to 2.5 km (1 to 1.5 miles) a day.

Young calves housed with one or more other calves eat more and therefore grow better. They also have fewer social problems when they are placed in a group with unfamiliar animals.

Introduction: Behavioural needs and feeding behaviour

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Feed and digestion in the cow

Anatomy of the digestive system, overview Rectum • absorbs water to reduce loss of fluids

Pancreas, gallbladder, small intestine • increase pH • add digestive enzymes • small intestine absorbs nutrients

Anus and vagina • average of 70 litres (19 US gallons) of urine and manure a day with 8-9% dry matter

Water and saliva

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Caecum, large intestine • gut flora ferment the remaining fibres and nutrients • absorb volatile fatty acids and water

Around 300 to 400 litres (80 to 105 US gal.) of water pass through the rumen of a lactating HF cow every day. Feed contains about 50 litres (13 US gal.) of water. A dairy cow drinks 4 to 5 litres of drinking water per kilogram of dry matter that she eats (0.5 to 0.6 US gal. per lb). This amounts to 80 to 120 litres (20 to 32 US gal.) of water a day at an ambient temperature of below 22 to 25°C (72 to 77 °F). And the animal produces 200 to 250 litres (53 to 66 US gal.) of saliva a day. This saliva: • moistens the feed and adds to the rumen fluid • prevents the rumen pH dropping too low • circulates nitrogen (urea) for protein production, as well as phosphorus and sodium. A lot of the water in the feed pulp is absorbed again by the omasum and the large intestine. Cows lose water in their milk, urine and manure, and it evaporates in their breath.

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Abomasum • adds gastric acid and enzymes • digests rumen flora and other nutrients • absorbs nutrients

Half of a cow’s saliva is produced when she chews, and the other half is produced continuously. If a cow doesn’t swallow or has a blockage in the oesophagus, saliva immediately starts drooling out of her mouth.

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Feed and digestion in the cow

Omasum • absorbs large amounts of water, volatile fatty acids and certain minerals • pumps feed pulp through

Throat, oesophagus • direct feed to the rumen • regurgitate the cud. Feed intake per day: 15-23 kg (33-51 lbs) dry matter = 30-90 kg (66-198 lbs) fresh weight

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Omasum orifice • blocks the floating mat and lets digested feed through

Rumen • contracts to mix contents • rumen flora break down the feed for their own energy and growth, producing volatile fatty acids • rumen wall absorbs volatile fatty acids and minerals. Volatile fatty acids meet 50-70% of the cow’s energy needs. Rumen content: 180-200 litre (48-53 US gal.)

Reticulum • regurgitates cud • pumps rumen contents around and to the omasum

Mouth, tongue, teeth • reduce and crush feed • add saliva (200-250 l/ day, 53-66 US gal./day)

Nose, eyes, tongue, muzzle • select feed and take it in Feed intake: • at pasture: 1 kg dry matter per hour • feed fence: 1.5-2 kg (3.3-4.4 lbs) dm per meal of approx. 1/2 hour

Rumen flora and free fatty acids as a food source

So a cow feeds itself from the rumen flora, the residual products from fermentation and nutrients that pass through the rumen and rumen flora. Volatile fatty acids are what is left over from the fermentation of carbohydrates (sugars, starch, cellulose). A dairy cow’s total volatile fatty acid production meets 50-70% of her energy needs. She gets the rest from starch in the small intestine, fat and protein. The feed pulp is fermented again in the caecum and large intestine. The volatile fatty acids produced there provide 10-15% of her energy.

The wall of the omasum is formed of leaf-like folds that resemble the pages of a book. This provides a very large contact surface area for the feed mass.

Introduction: Behavioural needs and feeding behaviour

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Rumen function: mixing, passage

Rumen function Rumen

1. Oesophagus

Photo: Owen Atkinson

Reticulum

Omasum Abomasum

Rumen fluid contains more than 1 billion microorganisms per millilitre – the rumen flora. This biomass consists of protozoa (4050%), bacteria (40 to 50%), fungi (5 to 10%) and archaea (1 to 2%). The large microorganisms in the photograph are protozoa (single celled organisms). The bacteria, archaea and fungi are not visible at this magnification (40x).

co pr py ot rig ec h te t d

In general, there are three layers present in the rumen: gas at the top, fluid at the bottom and a mass of recently eaten food floating on top of the fluid (the floating mat). With dairy rations there tend to be two layers: gas at the top and a floating mat consisting of food mixed with rumen fluid at the bottom.

When feed is eaten, it falls on top of the floating mat in the reticulum. The rumen movements mix it with rumen fluid and move it towards the back. Small, heavy feed particles sink down, becoming trapped in the floating mat. So the floating mat works as a kind of safety net and keeps small feed particles in the rumen for longer.

A healthy rumen contracts roughly twice a minute. You can feel this in the left-hand ‘hunger groove’. Make a fist and press it quite firmly against the hunger groove and wait. When the rumen contracts, your fist will be pressed outwards.

The reticulum contracts, pressing the floating mat against the oesophageal orifice, and the oesophagus sucks out a cud. To encourage rumination, the feed must contain sufficient particles of at least 2.5 cm in length. 8

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The rumen is empty and the cow has diarrhoea. This cow is sick, or the rumen contents are passing through too quickly.

Feeding Signals

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Rumen function: mixing, passage

4. In its mouth the cow extracts the moisture out of the cud and swallows it again. She then chews between 50 and 75 times, depending on what she can feel in her mouth. This process of remastication (re-chewing) reduces the size of the food and crushes it even further, increasing the surface area available to the rumen flora so that they are thoroughly mixed with the feed.

co pr py ot rig ec h te t d

The entrance to the omasum is in the oesophageal groove and acts as a sieve for feed particles passing through and those that remain in the rumen. If there is a smaller floating mat in the rumen and the reticulum, the omasal orifice will intercept far fewer small particles, so more feed that is less well fermented will pass through it. The smaller floating mat will then retain fewer small particles such as maize kernels.

The rumen wall absorbs volatile fatty acids very quickly. The speed differs from one cow to the next and also depends on the size of the rumen papillae. The rumen keeps its pH high by absorbing fatty acids. The rumen contractions cause the contents to flow past the papillae, providing a constant supply of volatile fatty acids.

The rumen wall is covered in papillae and looks a bit like a shag pile carpet. These papillae increase the surface area of the rumen by as much as 45 times.

6. The rumen flora ferment the feed, forming gas bubbles. These stick to the feed particle, causing it to float upwards. When fermentation is complete, gas stops forming and the particle sinks to the bottom where it is carried along towards the reticulum and the omasum via the undercurrent. Legend Microorganisms

Other feed particles

Regurgitated fibres

Gas formation

Ruminal villi

Fresh fibres

Regurgitated fibres/ fibres that have been in the rumen for a while

Introduction: Behavioural needs and feeding behaviour

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The rumen is empty and the cow has produced a lot of manure that looks well-digested. This cow is not eating enough.

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Digestion of feedstuffs

Rumen movements and feed passage Reticulum Oesophagus

Gas formation causes particles to ascend

Omasum

Particles sink (sedimentation) due to gravity

Rumen

Abomasum

Feed that has just been eaten stays at the top of the rumen and is pumped towards the reticulum. During rumination the oesophagus ‘bites off’ a lump of feed from the reticulum.

By contracting in certain ways, the rumen mixes the contents and creates a flow of fluid along the rumen wall and papillae.

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Roughly twice every five minutes, the rumen expels a quantity of gas.

Flow, speed, degradability

Floating mat

The floating mat is a pulp of fibrous, stalky feed particles in the rumen. The cow uses this for rumination, and it remains in the rumen for some time so that the rumen flora have enough time to ferment it. Small feed particles are also trapped by the floating mat and fermented for a long time. These feed fractions follow line 1 in the diagram. If there is only a small floating mat in the rumen or if the rumen contents are particularly acidic, small feed particles will flow through to the omasum very quickly. These follow line 2. Feed fractions that are not digested in the rumen are referred to as ‘undegradable’ (slowly digested). Feed fractions that are fermented very quickly in the rumen are referred to as ‘rapidly degradable’. Slow products such as brewer’s grains and beet pulp stabilise the rumen pH as they are fermented very gradually.

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The rumen creates various flows, including a flow of digested food towards the omasum. This is material from the bottom of the rumen.

Fibre consists of particles longer than 0.8 cm that help form the floating mat in the rumen. They are made up of the carbohydrates that give the plant stability: cellulose, hemicellulose and lignin. The longer it takes for these to ferment, the more they contribute to the floating mat. The quantity of lignin (ADL) in the fibre determines how slowly fermentation takes place. Products containing a large amount of lignin often feel hard or prickly to the touch. Cows usually chew these for a long time. Feed that is shorter than 0.8 cm (0.3 in) does not contribute to the floating mat even if it contains a large amount of slowly digestible fibres such as brewer’s grains and milled hay or straw.

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Energy and protein drive fermentation

Rumen and digestive system

Energy/protein ratio

Heart Liver

All the blood from the gastrointestinal tract first flows through the liver: 1,000-1,500 litres (260-400 US gal.) per hour. This converts all kinds of toxic and unusable substances into usable and safer substances, such as propionic acid into glucose, fatty acids into ketones, and ammonia into urea.

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The rumen flora ferment the feed which in turn enables them to multiply. To grow, the rumen flora need protein and energy in the right ratio. Nitrogen is an important building block of protein. If there is too little protein available in the rumen, this will slow down the fermentation rate. The rumen flora will then be exceedingly sparing with nitrogen, and levels of urea in the milk will be low. The rumen flora can produce some protein itself from nitrogen sources such as urea and ammonia. This is another aspect in which ruminants are unique. Energy can also be a restriction, causing protein to be used as a source of energy. When the rumen flora burn protein, nitrogen is released as ammonia (NH3). Ammonia is poisonous and is converted into urea in the liver. This process also uses more energy so even more ammonia is produced and more urea is formed. Excessive protein in the rumen is undesirable because it can put a strain on the cowâ&#x20AC;&#x2122;s liver, and protein is expensive. waxy layer epithelium

parenchyma

guard cell guard cell stoma

cells adjacent to cell walls

cell plasma plasma membrane

middle lamella lignin pectin

epithelium waxy layer bacteria fungi archaea protozoa

Plant cells consist of the cell contents surrounded by a cell membrane and a cell wall. Cell walls are made of cellulose and hemicellulose, glued together with pectin. All these carbohydrates are fermentable. The older the plant becomes, the more lignin (woody material) it forms in its cell walls.

The longer the feed stays in the rumen, the more cell plasma the rumen flora can reach and the more cellulose they can break down. The cell plasma contains about half the cellâ&#x20AC;&#x2122;s nutrients, particularly proteins, sugars, minerals and vitamins.

This manure is thin and contains undigested feed. You can see maize kernels and particles of maize meal. The feed passed through the rumen too quickly, so the small and large intestine were not able to digest the large supply of maize starch.

This manure is too thick and lumpy for a cow: it looks like horse manure. There was too little protein and energy available in the rumen. This sometimes happens with dry cows. They often have a very full rumen yet they can still lose weight due to a lack of energy.

Introduction: Behavioural needs and feeding behaviour

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Feed intake, milk production and rumen pH

Feed intake

The quantity of feed a cow can eat is mainly determined by the volume of her digestive system. There comes a point when nothing else will fi t inside. So feed that ferments quickly can be eaten in larger quantities because it passes through the rumen more quickly. But the length of time the cow has to eat and the palatability of the feed also play a role. On average, lactating cows eat 3% of their body weight in dry matter per day. For the average HF cow, this amounts to 21 kg (46 lbs) of dry matter per day.

Optimal fermentation rate high-producing cow

Consumption of nutrients for milk production

Rumen acidosis thin manure

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Rumen fermentation rate

To give more milk, cows must take in more energy and protein. This is achieved mainly by feeding them products that contain high levels of energy per kg (lb) dry matter. Many of these feeds encourage rapid production of many acids in the rumen and therefore increase the risk of rumen acidosis. An important challenge in feeding the modern dairy cow is to ensure that she takes in plenty of energy without harming her health. A too low rumen pH and starch passing through to the intestines too rapidly are the main risks. Producing 50 kg (110 lbs) of milk per day costs the cow: • (50 x 4.6% =) 2.3 kg (5.1 lbs) glucose in the form of lactose • (50 x 3.2-3.6% =) 1.6-1.8 kg (3.5-4.0 lbs) protein • (50 x 3.8-4.6% =) 1.9-2.3 kg (4.2-5.0 lbs) fat. Added to this is the energy she needs to produce these substances and the milk. The glucose is either produced by the liver from propionic acid or absorbed as glucose from rapidly-digested starch in the small intestine. If the cow takes in too little energy, she uses muscle protein to produce glucose and as a source of milk protein. She can also make protein from body fat, but not a great deal.

Balance between fibre and energy in the rumen

Insufficient energy intake solid manure

More milk = higher risk of rumen acidosis

Ration digests too slowly: lots of ADF, low digestion coefficient

Ration digested too quickly: sugars, degradable starch

Digestion rate of carbohydrates in ration

You want to aim for a very high energy intake because then the cow will give a lot of milk. But this increases the risk of rumen acidosis which can impact negatively on feed intake, feed utilisation and cow health.

160 (72) 140 (64) 120 (54) 100 (45) 80 (36) 60 (27) 40 (18) 20 (9) 4 (8.8)

8 (17.6)

12 (26.5)

Picture puzzle What are the success factors for keeping high-producing cows’ rumens healthy?

16 (35.2)

Feed intake, kg (lbs) dry matter per day

A high feed intake means a shorter chewing time per kg (lb) dry matter. High-producing cows eat a lot of feed and therefore chew relatively little. To remain healthy, they need to eat a lot of small meals spread over the day – 12 or more – and chew a lot.

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Yang et al., JDS, 2000

Chewing time in min. per kg (lb) dry matter

Chewing time in relation to feed intake

• • • • • • • •

Plenty of fresh water available Fresh, palatable feed in the manger all day long Plenty of fi bre in the feed Cows can reach the manger easily and without stress All cows can eat at the same time and without stress Each cow has plenty of time to eat the whole day Each cow eats the same feed at each meal Cows are healthy, well-rested, with no stress or pain

Feeding Signals

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Rumen pH

Every meal leads to a drop in pH. Fermentation of carbohydrates produces free fatty acids which reduce the pH value in the rumen. At a pH of above 6.0 the rumen function is optimal; below 5.8 indicates sub-optimal rumen acidity and below 5.5 means subacute rumen acidosis (SARA). Rumen acidosis causes poorer utilisation of the feed and damages the rumen wall. The rumen allows the contents to pass through more quickly, and the bacteria that ferment the crude fibre are ineffective at a low pH. Absorption of acids through the rumen wall is the most important mechanism for keeping the pH at the right level. This depends mainly on the metabolic capacity of the rumen wall cells combined with the surface area of the rumen papillae. The capacity to deal with acids varies between cows.

Risk period for rumen acidosis: start of lactation

pH development

Inflow of saliva with buffer: Rumination activity

Passage to abomasum: ‘pressure relief valve’

Absorption of fatty acids through rumen wall: length of rumen papillae and capacity

Buffer from blood

The processes that determine the rumen pH. If the rumen contents are not properly mixed, the pH can drop in places. The volume of the rumen contents also acts as a buffer: the more contents there are in the rumen, the less the pH will drop after a meal. Live yeasts in the feed can safeguard the rumen pH by moderating lactic acid production.

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Around calving the rumen wall does not yet have the maximum capacity for absorbing volatile fatty acids. It takes 2 to 3 weeks for the rumen papillae to reach their maximum size, depending on the starting point. It can take longer – anything up to 8 weeks – for the maximum absorption rate to be reached. The risk of rumen acidosis is therefore greater during the first eight weeks of lactation. The absorption capacity increases under the influence of volatile fatty acid production. You should therefore feed dry cows sufficient rapidly fermentable carbohydrates in the transition period (from 3 weeks before calving). If the pH is stable there will be fewer lactic acid forming bacteria in the rumen. Lactic acid formation is an important factor in the development of rumen acidosis because it is 10 times more acid than the other volatile fatty acids.

Inflow of rapidly fermentable sugar and starch: quantity per meal

10 to 14 meals per day, mixed ration:

Orange dotted line: the pH above which the rumen is safe

6 meals per day, mixed ration:

Dry matter intake and rumen pH

6.5

G. Oetzel, 1997, unpublished data

Average pH in rumen

7.0

6.0 5.5

5.0 25 (55) 30 (66) 35 (77) 40 (88) 45 (99) 50 (110) 55 (120) 60 (132) Dry matter intake in kg/day (lbs/day)

As can be seen in this graph, the more kilograms (lbs) of dry matter from an energy-rich ration a cow eats, the lower the average pH in her rumen. To avoid extreme pH peaks, therefore, the animal should eat small meals spread out well throughout the day.

An optimal rumen environment WE DEMAND WE WANT PH 6.0-6.5! PH 7.0! PH 5.5 IS THE DEATH OF US

8 meals per day, poorly mixed ration, cows 'sorting'

Cows that eat their rations in a large number of small meals have a more stable, higher pH on average due to the lower acid production per meal. Sudden intake of a large quantity of rapidly fermentable feed causes an extreme drop in pH followed by a period of not eating.

Introduction: Behavioural needs and feeding behaviour

voersignalen_lely UK.indd 13

A stable environment in the rumen creates the healthiest rumen flora and the best general health. Differences between meals can disturb the balance in the rumen flora. The rumen flora that ferment cellulose thrive best in a high pH environment. Starch and sugar fermenting flora prefer a slightly lower pH. Some rumen flora die off below pH 5.5. Live yeasts in the feed consume lactic acid, causing the pH to drop less.

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Feeding signals The Cow Signals Diamond

In addition, Feeding Signals shows you what you as a dairy farmer can do today to improve your feed management, with reliable information, short explanations and lots of images taken on working farms.

Feeding Signals is part of the Cow Signals® series. These books present highly practical knowledge on animal-focused dairy farming in an accessible way. ISBN 978-90-8740-156-6

9 789087 401566

Jan Hulsen Dries Aerden Jack Rodenburg

Health

Space

e Fe

Light

Jan Hulsen - Dries Aerden - Jack Rodenburg

An old Dutch farmers’ saying

co pr py ot rig ec h te t d

‘You feed with your eyes’

Feeding signals

About the authors

Feeding signals A practical guide to feeding dairy cows for health and production

www.roodbont.com

Cover Voersignalen stand UK.indd 1

www.vetvice.com

www.cowsignals.com

www.liba.be

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