Sheep - AgRIS

8.1.2 Supplementry feeding
The slaughter weight in Indian sheep is far lower and the age at which target weight is
achieved is far higher than expected. The system requires input of concentrate which although
cost effective, yet has not been adopted due to socio-economic conditions of the farmer. The
work done in the country on grazing with supplementation have indicated that in addition to
free grazing supplementation of limited quantity of concentrate amounting to 1.5 to 2.0 per cent
of body weight will provide marketable finishing weight of 25 and 30 kg at 6 and 9 months of
age respectively. The lambs under sole of grazing on Cenchrus pasture with concentrate
supplementation @ 1.5 per cent of their body weight achieved 26.7 kg at 6 months of age with
about 100 g average daily germ.
8.1.2.1 Maintenance requirements
An animal has to maintain itself before it is able to produce in the form of tissue growth,
development of foetus and milk or wool production. Maintenance requirments include the
requirements for basal metabolism (BM) plus the normal activity without any production.
Energy is the basic need to keep the animal‘s physiological processes going. The next is
nitrogen (protein) which is required to meet the normal wear and tear of tissues. Mineral and
vitamins are also needed to aid metabolic processes and normal tissue functioning. Several
experiments in India have shown that for maintenance of adult sheep weighing 30-40 kg,350 to
450 g of TDN per day are required. In other words, 10 g of TDN per day per kg body weight
should be ensured to maintain the weight of the animal.
Energy requirement
Energy requirement for maintenance could be met from grazing alone, if a well developed
pasture is available. Generally, during the period from January to June in arid and semi-arid
areas, the energy availability to the animal is even less than the maintenance requirment
thereby necessitating additional supplementation. The TDN content of the pasture, forage is
about 50-55% during lush green season and 35-40% during dry months. Assessment has to be
made at the local level whether the pasture available could maintain the animals. If the animals
are fed in stalls on legume hay or a high quality grass it is sufficient to maintain the animals.
The vegetation resources on the grazing land should be developed in 3 tier system (grass-shrubtrees).
No additional supplementation is required just to maintain the animal if sufficient
vegetation is available in the grazing area. The best system of management should be to leave
the animals to themselves in a paddock although the initial investment is very high to make a
paddock.
Protein Requirement
The protein requirment for maintaining the body weight of animal is based on the
metabolic faecal nitrogen (MFN) and the endogenous urinary nitrogen (EUN) excretion plus
the nitrogen requirements for normal growth of their hair and hoof and nitrogen loss from the
skin. About 2 mg of nitrogen or 12.5g of protein are required per kcal of basal heat
production. This value refers to protein actually needed in the replacement of nitrogen. In
actual feeding practice extra amount should be provided to allow for wastage in digestion and
metabolism. Provision of twice the amount of nitrogen/protein required per kcal of basal heat
would meet the maintenance requirement of the digestible protein. It is reported that 0.32 g of
DP kg body weight could maintain the weight of the rams (Singh et al., 1979). This value is
quite low compared to that reported by Gill and Negi (1971) who found 23 g of DCP was
required for a ram of 30 kg weight. A diet containing 3.4% DCP with a nutritive ratio of 1.13
was found to be adequate for maintenance of a ram (Sharma and Negi, 1977). Grazing studies
at Cental Sheep and Wool Research Institute,Bikaner have shown that even with low level of
digestible protein intake (7 to 9 g per day) during the period from Junuary to June, Marwari
ewes maintained weight. It appears that at low level of intake of protein, the animals recycled
nitrogen and met their protein requirements to maintain weight. On the basis of available data,
it can be concluded that in practical feeding conditions it would be desirable to provide 1g of
DCP per kg of live weight for maintenance of sheep. This requirement could easily be met if
legume fodder is fed or if the animals graze on green pastures. With dry pastures, during
summer or with feeding of straws or low quality grass hay, additional supplementation of
protein would be necessary.
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