Sheep - AgRIS

8.1.2.5 Concentrate and Hay feeding, feed lot experiments and their impact on growth,
carcass yield and quality
Post-weaning growth is primarily affected by hereditary factors, plane of nutrition,
prevailing meteorological conditions, animals ability to adapt to the environment and
managemental stresses. In agriculturally advanced countries post-weaning phase of growth is
mainly used for fattening and finishing purpose, whereas, in our intensive mutton production
strategies the active growth is completed by 5 to 6 months of age depending on the weaning age
of lambs. In view of lower growth rate of native sheep, under All India coordinated Research
Project on Mutton, improvement in their rate of gain and productivity was attempted through
crossbreeding local sheep with superior mutton breeds. The crossbred weaner (90 days) lambs
in 90 days intensive feeding exhibited superior growth rate (180 g average daily gain (ADG)
compared to their native (127 g ADG) counterparts. In view of similar growth performance of
different genetic lines of evolved crossbreds lambs, the defined exotic crosses were merged
together and renamed as Mutton synthetic. These Mutton synthetic (MS), Malpura selected
(IM) and Sonadi (S) weaner (90 days) lambs could achieve 170, 150 and 118 g—with 1:5 to 7
feed efficiency ratio under inten-sive feeding on 50:50 roughage (Pala leaf) and concentrate
based ration. In the experiment out of 99 MS lambs used, 90 percent lambs achieved finishing
weight of 30 kg live weight in 56 days of inten-sive feeding and out of 7 IM lambs 71 percent
achieved target weight in 66 days. Similarly fed native Nali, Chokla and their crosses with
Merino/Rambouillet weaner lambs had average daily gain of 111 to 135g with 1:12-15
feedefficiencyratio. Fastergaininfeedlotlambs is associated with higher fat content of carcass
some time exceeding 20 percent, hence, the weaning age of lambs can be reduced from 90 to 60
days to irnprove feed conversion efficiency, save higher feed input in undesirable fat deposition
and to provide early economic return. Accordingly lambs after weaning at 60 or 90 days were
put to feedlot experiment on a 50:50 roughage concentrate ration for further 90 days. The
Mutton Synthetic lambs had 160 and 151 g ADG, 16 and 12 percent feed efficiency,
respectively, in groups weaned at 60 and 90 days of age and respective figures for Malpura
lambs were 139 and 146 g ADG and 16 and 14 percent feed efficiency. In slaughter studies it
was observed that irrespective of age of slaughter and feeding regimen carcass of the finisher
lambs weigh ing around 25 kg and provided desirable carcass characteristics. In accordance
with th/e findings the lambs can be weaned at 60 days of age and fed intensively till they
achieved 25 kg live weight and slaughtered thereafter. In such feeding regimen also with 50:50
concentrate and roughage based feed lot ration, the MS; IM and MC lambs achieved finishing
weight of 25 kg in 73, 91 and 136 days of intensive feeding with 162, 135 and 112 g ADG and
18, 16 and 14 percent feed efficiency, respectively. Inaorporationdof different sources of
energy (maize, barley, jowar, bajra and damaged wheat) in feedlot rations of weaner lambs
indicated that all these sources could be effectively utilized in growing animals as their ADG
ranged between 92-114 g in different groups . Similarly while exploring use of different protein
supplements in feedlot ration (groundnut cake, cotton seed cake, mustard cake and guar meal)
and its complete replacement with urea it was observed that growth response was better with
groundnut and cotton seed cake (137 g ADG) compared to guar meal, mustard cake and urea
replacement (112 g ADG) groups.
8.1.2.6 Feed Compounding
The sheep production practices in our country are different from that in most of the
advanced sheep producing countries. The land left after grazing by large animals is generally
available for sheep. Thus sheep have to depend largely upon meager grazing on natural
vegetation, crop stubbles and straw and other agricultural and in dustrial by products that can
not otherwise be used by the human beings and large ruminants. For obtaining moderate
production from indigenous as well crossbred animals only grazing may serve the purpose but
in recent time under the situation where sheep are blamed for surface vegetation removal,
deforestation and soil erosion be- cause of their close grazing habits, then alternative feeding
practices are required to be adopted to obtain higher production under intensive feeding
management specially for fat lamb production. For this, available raw material be suitably
compounded to arrive at economical concentrate mixture. Research conducted in this area
indicated that feed mixture (crude protein content 16-17%) prepared by using equal quantity
oftree leaves, seasonal grasses, legume straws straws and kadbies along with coarse grain, bran
and oil cakes etc is ideal growth ration for fat lamb production. Feed conpounding should be an
important aspect of mutton production in future under the situation where grzaing land is
437