Sheep - AgRIS

eflected by increase in average fleece weight and decrease in average fibre diameter. The
improvement through such crossing has been quite substantial in Uttar Pradesh as neither the
rams of Rajasthan breeds nor their crosses face serious problem of survival as in the more hot
and humid southern states.
6.2.2.2 Crossbreeding with exotic breeds
The improvement in fine wool production can be brought about through selection for the
fleece weight and fleece quality. Although the fleece weight and fleece quality characters are
moderate to highly heritable (transmissible from parent to the progeny) and selection within the
native breeds will improve the wool production and quality, the progress through selection will
be a slow process because the level of performance of indigenous breeds is rather low. Earlier
experiments conducted for improving wool quality through selection have shown considerable
success. Such selective breeding against per cent medullated (hairy) fibres have been
undertaken on Deccani sheep at Sheep Breeding Research Station, Poona and on Bikaneri and
Lohi at Government Livestock Farm, Hisar. There was a considerable decrease in hairiness and
a correlated decrease in average fibre diameter (fibre fineness). Although evaluation of fleece
quality could be made visually, for more accurate evaluation, recording of fibre diameter and
medullation percentage would be necessary and this may not be possible for large scale
selection programme under field conditions.
For faster improvement, it may be desirable to upgrade the in-ferior wool producing breeds
with native superior wool producing breeds or by crossbreeding with exotic fine wool breeds.
Crossbreeding trials with exotic breeds botb Merino and British, have been undertaken
during pre-independence era and the results indicate marked ( 2 to 2.5 times) improvement in
wool production and considerable improvement in wool quality. Merino crosses were observed
to thrive better than those of British breed. Crossbreeding experiments carried out in a number
of states involving a number of exotic fine wool breeds indicate that Rambouillet crosses
performed better than Merino crosses and out of the native breeds the superior carpet wool
breed like Magra produce better crossbreds.
Results of crossing indigenous carpet wool breeds with exotic fine wool, mutton and dual
purpose breeds are presented in Table 6.2. Not only an improvement in greasy fleece
production but also in quality traits like decrease in average fibre diameter and medualltion
percenage was relatively perceptible in crosses than the native breeds. The meduallated fibres
in the crossbred wools were not only finer but also mostly heterotypic. Kemp was also reduced.
Some of these wools are liable to be graded as medium/superior carpet wool.
The results of crossbreeding experiments indicate that there is little difference among the
exotic fine wool breeds in crosses with the native breeds and there is substantial improvement
in greasy wool production especially in low fleece yielding breeds and in fleece quality as
reflected by a decline in average fibre diameter and medullation percentage. There is little
increase in greasy wool production beyond 50% exotic inheritance although there is further
improvement in fleece quality. In general the animals with 75% ex otic inheritance are more
disease susceptible and have higher mortality as is the experience of introducting the halfbreds
and 3/4th rams in the field in North-western region. The experience in Jammu & Kashmir,
however, indicates that under temperate and sub-temperate conditions it may be possible to
sustain 75% exotic fine wool inheritance. It is recommended that in north and southern hilly
regions exotic fine wool inheritance from Merino or Rambouillet may be introduced between
50 to 75% keeping in view the climatic and nutritional conditions and stabilized between these
levels through interbreeding. Further improvement should be brought in greasy fleece
production through selection and for this purpose, the state Government should have large
farms for producing stud breeding rams for distribution to the sheep breeders. In the Northwestern
arid region, the level of exotic fine wool inheritance may be stabilized at 50% and
further improvement in greasy wool production and quality especially the reduction in
medullation percentage may be brought about through selection.
The ad-hoc committee on sheep breeding policy also recommended that in Northern
temperate zone comprising of Jammu & Kashmir, Himachal Pradesh, and hilly regions of Uttar
Pradesh, the crossbreeding with Rambouillet and/or Merino should be undertaken for
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