2 NUTRIENT REQUIREMENTS OF ANIMALS
NUTRIENT REQUIREMENTS OF SHEEF; GOAT AND RABBIT
mm. ICAR
Indian Council of Agricultural Research New Delhi
PRINTED THIRD EDITION 2013 SECOND EDITION 2013
Project Director Incharge (English Editorial Unit) Editor
Chief Production Officer Technical Officer (Production) Cover Design
JULY 2013
SHEEP AND GOAT RABBIT
Dr Rameshwar Singh Dr R P Sharma Reena Kandwal Dr V K Bharti Punit Bhasin Dr V K Bharti and Punit Bhasin
Correct Citation:
Nutrient Requirements of Animals - Sheep, Goat and Rabbit (ICAR-NIANP), 2013
Š 2013, All rights reserved Indian Council of Agricultural Research, New Delhi
ISBN: 978-81-7164-137-6
Price: ?200
Published by Dr Rameshwar Singh, Project Director, Directorate of Knowledge Management in Agriculture, Indian Council of Agricultural Research, New Delhi 110 012; Lasertypeset at M/s Dot & Design, D-35, Ranjeet Nagar Comm. Complex, New Delhi 110 008 and printed at M/s Royal Offset Printers, A-89/1, Naraina Industrial Area, Phase I, New Delhi 110 028.
CONTENTS SI. No.
Page No.
Tide Sheep
1. 2.
3.
Introduction
1
2 3 3 6 10 11 12 13 16 18 24
Feeding systems Nutrient requirements Maintenance Growth Gestation and lactation Wool production
4.
5.
Range sheep Minerals Vitamins
References List of Tables
Goat 1.
Introduction
25
2.
Feeding Systems Extensive System Semi-Intensive System Intensive System Dry Matter Intake Energy
26 26 27 27
3.
Protein Minerals Vitamins
27 29 29 29 30
4.
Water
31
5.
Nutrient Requirements Maintenance Growth Lactation
32 33
Reproduction
37
35 35
x
NUTRIENT REQUIREMENTS OF SHEEP, GOAT AND RABBIT
SI. No. 6.
7. 8.
Title
Page No.
Creep Feeding Flushing Feed Formulation
37
38
Concentrates Total Mixed Ration (Complete Feeds) 9.
10.
38 39 40
Strategic Supplementation Round the year Forage System
40
References
42
Annexures
44
A1 Concentrate supplements using locally available feed resources
44
A2 TMRs using locally available feed resources
44
List of Tables
45
41
Rabbit 1.
Introduction
46
2.
Feeding systems
47
3.
Energy and its sources
48
4.
Protein and amino acids
49
5.
Minerals
50
6.
Vitamins
50
7.
Feed formulation
51
References List of Tables
51
52
SHEEP Introduction Sheep, an important component of livestock farming are reared mosdy on grazing in all the climatic conditions that prevail inIndia. Their population was 39.1 million during 1951 which has increased by nearly 90 per cent to 74.0 million heads by 2010. They produced 44,400 tonnes of wool and 0.369 million tonnes of meat during 2010-11 (DAHDF, 2012). Sheep reared in western Rajasthan are famous for their carpet wool. Sheep in NorthÂŹ west Himalayanregion produce apparel quality wool. Other regions produce coarse wool that has industrial use. The demand for animal-based food products is on increase. Between 1981 and 2000 per capita consumption of meat in India increased by 22 per cent compared to 4 per cent increase in the consumption of food grains (Kumar etal., 2003). This will continue to rise in the future (Rao et al., 2004). However, the growth of the livestock sector is affected due to the shortage of feed and fodder. Common property resources (CPRs) - the common grazing land, pasture and wastelandsprovide large proportion of nutritional requirements of sheep and goats in India. The resource-poor farmers depend on CPRs as compared to the rich farmers. Now intensive/ semi-intensive feeding systems are also being adapted because of the decline in the quality and quantity of CPRs.
si
~ÂŁtn Marwari Rams
* Malpura Ram
Indian sheep are highly heterogeneous in terms of live weight and production traits. The adult body weight of sheep ranges from 15 kg (Garol) to nearly 50 kg (Patanwadi, Marwari and Magra). Likewise there is large variation in weaning weight, rate of growth etc. The ICAR first published the nutrient requirements of Indian sheep in 1985 which was subsequently revised in 1998. During the last decade lot of work has been carried out on different aspects of sheep nutrition. Information collectedhas been included in this publication.
2
NUTRIENT REQUIREMENTS OF SHEEP, GOAT AND RABBIT
Feeding Systems
Sheep rearing in India is mainly based on extensive grazing system. The performance of sheep under extensive system varies depending on the quality and quantity of herbage available. Swards available for grazing depend on the intensity ofrainfall. Indiareceives nearly 80 per cent ofrainfall during 4 months of monsoon. During this period grasses are succulent and animals often fall short of energy intake due to gut fill effect. After the monsoon grasses mature, there is a decline in protein content and increase in lingocellulose fraction. In western Rajasthan, sheep flocks often migrate to nearby states - Punjab, Haryana, Uttar Pradesh and Madhya Pradesh-as there is a shortage of grazing resources in their native tract. Under semi-intensive system, sheep are allowed to graze in the CPRs or cultivable/fallow land for 8 to 12 hours a day and then offered homeÂŹ made/ commercial concentrate mixture. At times, diets are supplemented with good-quality leguminous straws of guar, moth, moong, groundnut and gram. In this system there are fewer fluctuations in the production parameters than under extensive system. However, for sheep farming under sub-urban areas intensive systems are preferred.
*
m
|ggg Magra Sheep
Chokla Sheep
The advantage of intensive feeding system is that there is a complete control over the feed. There are three sub-systems prevailing under intensive management: a) roughage and concentrates are offered to sheep in cafeteria mode; b) limited quantity of concentrate is offered along with ad lib roughage; and c) roughage and concentrate are offered in the form of complete feeds. The intensive system is immune to agro-meteorological variations and at the same time it offers flexibility in modulating the production system. The system can be well adapted to rearing sheep for fat lamb production of desired traits.
NUTRIENT REQUIREMENTS OF ANIMALS
3
Nutrient Requirement Nutrients needed for meeting the requirements for different production functions are the part of dry matter (DM). It is established that with increasing body weight, DM intake in terms of per cent body weight decreases. The estimated requirement of DM for maintenance, growth, gestation and lactation is given in Table 1. Proteins are the main building blocks of the all animal tissues. They are the major contents of wool, meat and milk. Sheep by virtue of being a ruminant, synthesize microbial protein from non-protein nitrogen sources and from dietary protein sources. Ruminally fermented energy or organic matter is one of the important factors that influence microbial protein synthesis. The availability of adequate amount of nitrogenous compounds in the rumen to meet microbial growth requirement is the most important factor. Another important factor related to crude protein need of sheep is urea recycling. Ammonia not used for microbial protein synthesis is absorbed and transported to liver where it is converted into urea (Milano et al., 2000). The urea synthesized in the liver is recycled into the rumen for microbial protein synthesis. Estimates indicated that 42 (Ford andMilligan, 1970) to 61percent (LobleyrTa/., 2000) of urea synthesized is recycled in the rumen. The proportion of urea recycled for microbial proteins in the rumen however depends on the level of intake, type of diet and fermentable energy intake.
Maintenance Requirement Energy required by the sheep primarily is to maintain basal metabolic When the animal is in homeostasis it is considered as meeting the maintenance requirement. Energy requirement is affected by factors such as age, gender, body composition, season, parasitism, type of diet, distance travelled during grazing, and environment. Fasting heat production and metabolizable energy required for maintenance (MEm) decreases as animal ages (NRC, 2007). A curvilinear relationship exists between fasting heat production and advancing age (Freetly et al., 2002). Kearl (1982) suggested MEm of 92 kcal/kg W0 75. One of the factors that influence MEm is level of feed intake (NRC, 2007). As per the Feeding Standards for Australian Livestock (SCA, 1990), MEm varies in relation to ME intake to account for the effect of level of feed intake on energy expenditure by body tissues. Sheep cover long distances duringgrazing, so MEm requirements for grazing sheep will always be higher than for the restrained animals. Estimates of the energy cost of walking were 3.35 (0.80 cal), 31.7 J (7.58 cal) and 13.2 J (3.15 cal)/kg BW/m for horizontal, ascending and descending movement, respectively (Lachica and Aguilera, 2005). SCA (1990) presented prediction equations with independent variables of dry matter (DM) digestibility, terrain rates.
4
NUTRIENT REQUIREMENTS OF SHEEP, GOAT AND RABBIT
score, availability of green or total forage and BW The migration of sheep flocks to long distances for grazing is an acceptable phenomenon in the country. So an adjustment for activity allowance inMEm is required. Paul et al. (2003) estimated the total digestible nutrients (TDN) requirement as 37.0 or 35.3 g/kg W0 75 for BW that ranged between 7 and 15 kg or 15.5 and 30 kg, respectively. Thus MEm was 560 kj (134 kcal) /kg W0-75 or 534 kj (127.8 kcal)/ kg W075 for BW that ranged from 7 to 15 kg or 15.5 to 30 kg, respectively Patle et al. (1991) estimated maintenance requirement of TDN/ MEm for growing sheep of Bikaner breed as 33.34 g TDN (120.36 kcal /kg W0 75). Data generated inIndian researchinstitutions indicated that an intake of 4.16 MJ (1.0 Meal) each day was required as MEm for housed sheep; it increases by 43% for grazing animals (Singh et al., 2004). A higher maintenance requirement (MJ/d) is therefore prescribed for different seasons, viz. winter, 4.85 (1.16 Meal); summer, 5.85 (1.40 Meal); and rainy 6.70 (1.60 Meal) (Shinde et al., 1998). Average ME requirement for maintenance of housed sheep was 90-100 keal/kg W0 75, it increased by 25% for sheep grazing on developed pasture, by 50% for those grazing on open ranges duringmigration and by 75% for those grazing on ranges under hot and arid environments. Data are not available on MEm requirements of migratory sheep flocks that followed an annual cycle of upward (4,000-5,000 m above mean sea level) and downward migration (plains), and were exposed to a variable degree of grazing andenvironmental stresses. The suggested requirement of energy for maintenance is given in Table 1. Protein requirement for maintenance includes losses of nitrogen in faeces, urine, skin and fibre. Maintenance requirement of protein relative to BW or kg W0-75 was determined by regression of intake against performance (NRC, 2007). Tropical animal rearing at times depends much on tree/ shrub leaves. Many of these contain condensed tannins (CT). These can increase faecal nitrogen excretion and in turn decrease apparent digestibility of nitrogen. The estimates of maintenance requirements of digestible crude protein (DCP) were 4.43 and 4.49 g/kg W째 75 for BW of 7-15 kg or 15.530 kg respectively (Paul etal., 2003). A mature sheep produces 2-6 g clean wool/d; therefore the DCP (Table 1) also covers the requirements for wool
production. Efforts were made to understand the interaction between the nutrition of the animal and parasitism and the subject has been extensively reviewed (Swarnkar and Singh, 2005). In infected animal, the reduction in feed intake couldbe immuno-stimulatory that allow the host to become more selective in their diet. The reduction in nutrient availability to infected animal is probably through both reductions in feed intake and/or reduction in efficiency of absorbed nutrients that further depend upon the species of
NUTRIENT REQUIREMENTS OF ANIMALS
5
parasites and its location in the gastro-intestinal tract. To maintain body growth in infected animals, protein requirement is increased due to loss or diversion of endogenous nitrogen. Therefore, in the event of infestation, animals would require a high feed energy intake, with a high ratio of amino acids to ME, higher rate of absorption of calcium and phosphorus. Table 1 . Nutrient requirements of Indian sheep (adult ewe, rams, yearlings) for maintenance, breeding, gestation and lactation
BVV (kg)
Energy in Diet (ME, Meal/ kg)
Maintenance 10 2.0 15 2.0 20 2.0 2.0 25 30 2.0 35 2.0 40 2.0 45 2.0 2.0 50 2.0 55 60 2.0 2.0 65 2.0 70 Breeding 2.0 15 20 2.0 2.0 25 30 2.0 35 2.0 2.0 40 2.0 45 50 2.0 2.0 55 2.0 60 2.0 65 2.0 70 Gestation 15 2.4 20
25 30 35 40
2.4 2.4 2.4 2.4 2.4
DMI (g/d)
DMI (% BW)
Energy requirement
Protein requirement
TDN(g)
ME(Mcal)
CP(g)
DCP(g)
0.91 1.00 1.10 1.19 1.27 1.36 1.44 1.53
3.50 3.16 2.94 2.78 2.66 2.56 2.47 2.40 2.34 2.28 2.23 2.19 2.15
0.20 0.27 0.33 0.39 0.45 0.50 0.56 0.61 0.66 0.71 0.75 0.80 0.85
0.70 0.95 1.18 1.39 1.59 1.79 1.98 2.16 2.34 2.51 2.68 2.85 3.01
38 51 63 75 86 96 107 116 126 135 145 153 162
25 34 43 50 58 65 71 78 84 91 97 103 107
0.53 0.66 0.78 0.89 1.00 1.10 1.21 1.30 1.40 1.50 1.59 1.68
3.53 3.28 3.10 2.97 2.85 2.76 2.68 2.61 2.55 2.49 2.44 2.40
0.29 0.36
56 70 82 95 106 117 128 139 149 159 169 178
38 47
0.49 0.55 0.61 0.67 0.72 0.78 0.83 0.88 0.93
1.06 1.31 1.55 1.78 2.00 2.21 2.41 2.61 2.80 2.99 3.18 3.36
63 71 79 86 93 100 106 113 120
0.60 0.75 0.88 1.01 1.13 1.25
4.01 3.73 3.53 3.37 3.24 3.14
0.40 0.50 0.59 0.67 0.75 0.83
1.44 1.79 2.12 2.43 2.72 3.01
77 95 112 129 145 160
51 64 75 86 97 107
0.35 0.48 0.60 0.71 0,81
0,43
55
6
BW (kg)
NUTRIENT REQUIREMENTS OF SHEEP, GOAT AND RABBIT
Enesrgy in
DMI (g/d)
DMI (% BW)
2.4 2.4 2.4 2.4 2.4 2.4
1.37 1.48 1.59 1.70 1.81 1.91
3.05 2.97 2.90 2.83 2.78 2.73
TDN(g) 0.91 0.99 1.06 1.13 1.20 1.27
ME(Mcal) 3.29 3.56 3.82 4.08 4.33 4.58
CP(g) 175
2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4
0.72 0.90 1.06 1.21 1.36 1.51 1.64 1.78 1.91 2.04 2.17 2.29
4.81 4.48 4.23 4.04 3.89 3.76 3.66 3.56 3.48 3.40 3.33 3.27
0.48 0.60 0.70 0.81 0.91 1.00 1.09 1.18 1.27 1.36 1.44 1.52
1.73 2.15 2.54 2.91 3.27 3.61 3.95
92 114 135 155 174 192 210 227 244 260 276 292
Diet (ME, Meal/ kg)
45 50 55 60 65 70 Lactation 15 20 25 30 35 40 45 50 55 60 65 70
Energy requirement
4.27 4.59 4.90 5.20 5.50
Protein requirement
203 217 230 243
DCP(g) 117 127 136 145 154 163 62 76 90 104 116 129 140 152 163
174 185 196
Growth
Among other studies on nutrient intake, its utilization and growth of native sheep (Bhatta et d., 2002; Tripathi etd., 2006; Tripathi and Karim, 2011; Raghuvansi et d., 2007; Karimand Santra, 2000; Santra and Karim, 2000, 2002; Santra et al., 2002) and crossbred sheep (Karim and Santra, 2000; Santra and Karim, 2001; Tripathi et d., 2001, 2007; Santra et d., 2002; Anil Kumar et d. 2002; Singh et d. 2006 and Tripathi et d., 2011) were considered for arriving at the growth requirement. Newborn lambs (1-3 days old) require 117 kcal ME/kg W075 for maintenance and 0.41 kcal ME/g gain in weight (Kearl, 1982). The preÂŹ weaning growth period is crucial. A daily gain of 137 to 163 g could be achieved withDMintake of 3.6 to 4.0 per cent oflive weight and maintaining an intake of 42.2 to 59.9 g DCP and 4.19 to 5.91MJ (1.41 Meal) ME per day. The required dietary ME ranged from 8.0 to 8.9 MJ (1.91 to 2.12 Meal) per kg and DCP from 7.5 to 8.5 per cent (Tripathi et d., 2011). The CP requirement of 681 g (range 444 to 838 g), ME of 5.14 MJ (1.23 Meal) and DM of 4.2 kg (between 3.7 to 4.9 kg) was needed for every kg of gain during pre-weaning phase of growth. An ADGof 150 g was achieved in pre-weaner lambs when fed a diet containing 8.22 MJ (1.96 Meal) ME and 80 g DCP /kg with DMI of 629 g DM (3.6 % of BW). Crossbred
NUTRIENT REQUIREMENTS OF ANIMALS
7
lambs during post-weaning phase of growth required dietary ME 10.4 MJ (2.49 M cal) in each kg diet and DCP 10.4 per cent to have average daily gain of 112 g (46 to 162 g). A diet that had 32-35 g DCP/Mcal ME was recommended for ADG ranging from 130 tol60 g (Singh et al., 2004). The maintenance requirement of growing sheep is 37.0 g/kg W0 75TDN, 6.68 g/kg W0-75 CP and 4.43 g/kg W0 75 DCP for BW of 7-15 kg; and 35.3, 6.98 and 4.49 g for the BW of 15-30 kg. The corresponding requirements for gain (g/d) in BW were 0.91, 0.47, and 0.31 g for 715 kg BV\( and 1.21, 0.43 and 0.30 gfor 15-30 kgBW (Paul etal., 2003). ME was calculated from TDN values using a factor of 1 kg TDN=15.13 MJME (NRC, 1985). The nutrient requirement for growing sheep is presented in Table 2. Table 2. Daily nutrient requirements of growing Indian sheep BW
(kg)
ADG (g/d)
ME level in diet (Mcal/kg)
DMI (kg/d)
DMI (% BW)
25 50 75 100 150 25 50 75 100 125 150 200 25 50 75 100 125 150 200 250 25 50 75 100 125 150 200
2.40 2.53 2.53 2.71 2.89 2.00 2.00 2.40 2.40 2.40 2.40 2.40 2.00 2.00 2.00 2.40 2.40 2.40 2.40 2.40 2.00 2.00 2.00 2.40 2.40 2.40 2.40
0.22 0.24 0.27 0.29 0.33 0.35 0.38 0.40 0.43 0.46 0.49 0.56 0.55 0.59 0.63 0.56
4.4 4.8 5.5 5.8 6.5 3.5 3.8 4.0 4.3 4.6 4.9 5.6 3.7 3.9 4.2 3.8 4.0 4.2 4.7 5.1 3.3 3.6 3.8 3.4 3.6 3.9 4.3
Energy requirement
TDN(g) 5 5 5 5 5 10 10 10 10 10
10 10 15 15 15 15 15 15 15 15 20 20 20 20 20 20 20
0.60 0.63 0.70 0.77 0.66 0.71 0.77 0.68 0.73 0.78 0.87
146 169 192 215
260 231 253 276 299 322 344 390 305
328 350 373 396 418 464 509 364 394 425 455 485 516 576
ME(Mcal) 0.53 0.61 0.69 0.78 0.94 0.83 0.91 1.00 1.08 1.16 1.24 1.41 1.10 1.18 1.26 1.35 1.43 1.51 1.68 1.84 1.31 1.42 1.53 1.64 1.75 1.86 2.08
Protein requirement
CP(g) 34 46 58 69 93 61 73 84 96 108 131 63 74
97 110 121 145 168 77 87 109 120 130 152
DCP(g) 23 30 38 46 61 33 40 48 56 64
71 87 42 49 57 65 73 80 96 111 50 57 65 72 80 87 102
8
NUTRIENT REQUIREMENTS OF SHEEP, GOAT AND RABBIT
BW (kg)
ADG (g/d)
20 25 25 25 25 25 25 25 25 30 30 30 30 30 30 30
250 25 50
30 35 35 35
250
35 35 35 35 35
75 100 125 150 200 250 25 50
75 100 125 150 200
25 50 75 100 125 150 200 250
ME level DMI DMI in diet (kg/d) (% BW) (Mcal/kg)
2.40 2.00 2.00 2.00 2.40 2.40 2.40 2.40 2.40 2.00 2.00 2.00 2.00 2.00 2.40 2.40 2.40 2.00 2.00 2.00 2.40 2.40 2.40 2.40 2.40
0.96 0.77 0.82 0.88 0.78 0.82 0.87 0.96 1.05 0.87 0.93 0.98 1.04 1.09 0.95 1.05 1.14 0.97 1.03 1.08 0.95 0.99 1.04 1.13 1.22
4.8 3.1 3.3 3.5 3.1 3.3 3.5 3.8 4.2 2.9 3.1 3.3 3.5 3.6 3.2 3.5 3.8 2.8 2.9 3.1 2.7 2.8 3.0 3.2 3.5
Energy requirement
TDN(g) 637 425 455 485 516 546 576 637 698 483 513 543 574 604 634 695 755 538 568 599 629
689 750 810
Protein requirement
ME(Mcal) 2.30 1.53 1.64 1.75 1.86 1.97 2.08 2.30 2.52
CP(g) 173
1.74
100 110 122 132 143 153 175 197 111 122 133 143 154 165 186 208
1.85 1.96 2.07 2.18 2.29 2.51 2.73 1.94 2.05 2.16
2.27 2.38 2.49 2.71 2.92
99 110 121 132 142 164 185
DCP(g) 117 58 65 73 80 88 95 110 125 65 72
80 95 103 117 133 72 80 87 95 102 110 125 140
Native lambs require a diet having 9.5 MJ (2.27 Meal) ME and 9.04 % DCP for ADG of 124 g. On DM intake between 2.4 and 5.0 per cent (mean of 3.52 %), the native lambs attained ADG of 142 g (97.6 to 196 g). Crossbred lambs had ADG of 112 g (46 to 162 g) on feed that had 10.4 MJ (2.49 Meal) per leg diet ME and 10.44% DCP. Paul ct al. (2003) estimated the ME requirement for growth as 13.7 kj (3.29kcal) and 18.3 kj (4.37kcal) per g BW gain for body weight of 7-15 kg and 15.5-30 kg, respectively. The corresponding values for TDN requirements were 0.91 and 1.21g per g BW gain.
Nutrition of pre-weaner lambs Colostrum provides critical nutrients to sucking lambs. Pre-weaning growth also affects post-weaning growth as a result, enhanced growth (ADG up to 165 g) and weaning weight of 17.4 kg can be achieved (Tripathi et al., 2011). The pre-weaner lambs on free suckling andadlib. creep mixture
NUTRIENT REQUIREMENTS OF ANIMALS
9
feeding with varying levels of CP indicatedthat 18% CP in the creep mixture is adequate for the desired rate of gain of pre-weaner lambs. The lambs in pre-weaning phase on an average consumed 83 g DM, 12.0 g DCP and 48 g total digestible nutrient (TDN)/kg W0 75 amounting to 54 g DCP/Mcal digestible energy (DE) for 140 g ADG. Early rumen development is also known to improve weaning weights. A diet containing 8.45 MJ (2.02Meal) ME and 80 g DCP/kg of feed DM was found to be optimum (Tripathi et al., 2007). Live microbes feeding facilitates early establishment of rumen microflora and rumen development. Milk replacer feeding During the first week of life, suckling of dam’s milk primarily influences lambs’ growth and development. Lambs that have inadequate milk during the first month oflife are more prone to infectious diseases and show overall poor growth. Lambs less than four weeks of age may be fed milk replacer rich in milk fat and quality protein. This alternate feeding arrangement is also important to foster orphan or separated lambs. Lambs below 30 days are functionally similar to non-ruminants, therefore quality of protein is important. The lambs start nibbling on feeds within few days of birth and consume very little in terms of dry matter. Although feed intake is minimal during early age, it is important to introduce creep feed to the lambs at 10 days of age. Milk replacers with added prebiotic and probiotic preparations improve pre-weaning growth, and in turn weaning weights. Addition of lectulose or mannan oligosaccharides (3%) in milk replacer and a probiotic at the rate of 109 CFU (colony forming unit)/kg after one week of birth increases intake, body weight and affects the morphology of the small and large intestine in pre-weaning stage (Bhatt et al., 2008) .
Creep mixture feeding Creep mixture feeding is a simple way to allow lambs access to extra feed supplements. This means that the lamb is suckling milk and grazing but have extra supplements to make up any shortfall in their intake. Lambs usually commence creep feeding around 10 to 14 days of age, and the amount consumed is inversely proportional to the amount of milk consumed. Inadequate energy intake by suckling lambs is the major cause of slow weight gains. Greater efficiency andlamb weight gains occur if lambs are creep fed. The amount of creep feed consumed by the lambs at 2 to 6 weeks of age is affected by the palatability of the ration (composition and form). Low milk yield of the dam tends to encourage creep consumption but in general the growth of the lamb is affected by the birth weight and milk consumption. Soybean meal is an important ingredient in creep diets because of its high protein content and palatability. For rapid weight gains creep diets must be
10
NUTRIENT REQUIREMENTS OF SHEEP, GOAT AND RABBIT
palatable, contain high energy and adequate protein (14 to 18%), minerals, especially calcium with an ideal calcium to phosphorus ratio of 2:1 and adequate vitamin levels. Gestation and lactation A pregnant sheep need nutrients for foetus, uterus and mammary gland andrelated organs. During the last trimester of pregnancy most of the energy is used by the foetus. Efficiency of energy use in pregnancy is low in comparison to growth or maintenance (NRC, 2007). ICAR (1998) proposed ME requirement of pregnant sheep as 71 - 80 kcal ME per kg BW NRC (1985) suggested requirements for gestation on the basis of birth weight of the lamb, litter size and gestation length. The energy and protein requirement for gestation are given in Table 1. The requirement of energy for lactation depends on the amount and composition of milk. The amount of nutrients required is also dependent upon the number of lambs nursed. The peak milk production in ewes is achieved at around 21 days of lactation and high milk production levels are sustained for 6-8 weeks of lactation. Nutrient requirements are based on the projected milk yield whenindividuallambs are gaining at 75, 65 and 50 g/d, for singles, twins, and triplets respectively from birth to weaning. Calculations are based on the assumption that 0.8 kg milk is required for 200 g gain in nursing lamb, when creep feed is available and llcg of milk without creep feed. Protein and energy are both critical nutrients for milk production. The requirement for milk protein synthesis is determined by the amino acid profile and milk out-put. If either of the nutrient is fed below the requirement, milk yields and subsequently lamb gains tends to reduce. Almost all the ewes lose weight during lactation, because energy intake is well below the requirements and ewes must mobilize body reserves to sustain milk production. Hence, weight loss during early lactation is critical. Therefore, late gestation nutrition should be adequate enough to ensure ewes to regain their average or better body condition at lambing. Traditionally, fat mobilization during lactation was considered as a means of controlling feed costs. However, excess weight loss is not without its costs. Ewes losing less than 0.5 condition score during 60-day lactation will not suffer in terms of milk yield. Since one ‘condition score’ equates to 11% change in body weight. Weight loss during lactation impacts protein requirements, i.e. the more weight ewes lose the higher their protein need. This situation is due to the ewe’s ability to effectively mobilize body fat but having minimal ability to mobilize body protein for milk synthesis. At times it is economical to feed more energy rich grain to limit weight loss instead of feeding extra protein to balance energy from fat breakdown. It is also important to realize that fat conversion to milk is about 60% under protein
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