DOI Number: 10.5958/2277-940X.2015.00039.X Non-Genetic Factors Affecting Growth and Production Traits in Dorper Crossbred Sheep Vikas bin Zaffer, Raman K. Taggar and Dibyendu Chakraborty * Division of Animal Genetics and Breeding FVSc & AH, SKUAST-Jammu, R. S. Pura, Jammu, J & K, INDIA *Corresponding author: D Chakraborty; dibyendu_vet40@yahoo.co.in Received: 04 September, 2014 Accepted: 30 May, 2015 ABSTRACT Data on growth traits of 401 animals used in the present study were collected from history sheet of crossbred sheep maintained at Government Sheep Breeding Farm Panthal, Reasi, J&K, India. Traits included in the study were birth weight (BWT), weaning weight (WWT), 6-month body weight (6-BW), 12-month body weight (12-BW), mature body weight (MBW) and annual wool production (AWP). The statistical analysis was carried out using LSMLMW computer programme. The overall least-squares means were 2.857 ± 0.058 kg, 15.269 ± 0.296 kg, 17.034 ± 0.258 kg, 22.315 ± 0.298 kg, 29.375 ± 0.237 kg and 0.651 ± 0.012 kg, respectively for BWT, WWT, 6-BW, 12-BW, MBW and AWP. The co-effcient of variations for different traits were low to moderate. Period of lambing had signifcant effect on all the traits except for BWT. Moreover, there was no defnite trend for different traits over different periods except for 12-BW, where increasing trend was obtained. Season of lambing had signifcant effect only on WWT and MBW. Genetic group had non-signifcant effect on all the traits under study although, 50% genetic groups were superior for most of the traits. Sex had signifcant effect on all the traits except for 6-BW and 12-BW. It can be concluded from the study that growth traits and production traits are infuenced by different non-genetic factors like period, season and sex. Keywords: Growth traits, Non-genetic factors, Dorper crossbred sheep, Annual wool production. Improved production from our native sheep breeds is, therefore, need of the day and to achieve broad avenues appear to be open. Either the sheep at hand must be induced to yield more by selective breeding or to secure concentrated doses of good genes as replacement from improved exotic breed into our native sheep breeds, which can rather quickly transfer good qualities of exotic breeds in our animals. The genetic improvement can be done, either by selection or by cross-breeding the indigenous breeds with exotic fne wool breeds. Selection of genetically superior animals is infuenced by non-genetic factors such as year, season and sex etc. due to which there is diffculty in estimating the differences in breeding values of individuals being selected, therefore identifcation and their correction factors will help in estimation of genetic parameters. The improvement on account of selection could be achieved only after several generations, but by crossbreeding the desirable goal can be achieved in short span of time. Birth weight, weaning weight, 6-month weight and 12-month weight are the indicators of individual performance and they have direct effect on the productivity and health status of sheep. These are the important factors as they infuence lamb’s survival and growth. The animals weighing heavier at birth and weaning have a better survivability and may grow faster and likely to increase the overall productivity. Early growth traits are important factors infuencing proftability in any meat producing enterprise. The birth weight of an animal and its early growth rate are highly infuenced by genetic potential of sheep. Therefore, genetic studies on growth and production traits will be ideal model for future on the basis of which selection can Journal of Animal Research: v.5 n.2, p. 227-230. June 2015