Phenotypic and Genetic trends in Corriedale Sheep under temperate conditions

Abstract Sheep constitute an important genetic resource to the J&K, India. Considering its worth, the Corriedale breed was imported for improving the production potential of sheep in J&K, India which has since been maintained at SKUAST K. The current study was undertaken to study the phenotypic, heritability and genetic trends of the Corriedale breed over the years under temperate climatic conditions. Data for Corriedale breed from 1969 to 2016 was collected from Mountain Research Station for Sheep and Goat, SKUAST K for birthweight, weaning weight, 6-month weight, 9-month weight and 12-month weight. Mean phenotypic values, heritability estimates and breeding values using BLUP animal model were used for regression on the birth year to estimate trends over four decades. A decline from 3.81kg to 3.84 kg for birthweight, 16.7 kg to 12.184 kg for weaning weight, 21.03 kg to 15.256 kg for 6-month bodyweight, 24.085 kg to 18.212 kg for 9-month body weight and 28.337 kg to 21.122 kg for 12-month body weight was seen from 1969 to 2017 in Corriedale Sheep. A change in EBV’s for birthweight, weaning weight, 6-month body weight, 9-month body weight and 12-month body weight from 0.00206 ± 0.0067, -0.00114 ± 0.0093, -0.00203 ± 0.0138, 0.00665 ± 0.0130, -0.00061 ± 0.0078 respectively to 0.00103 ± 0.0070, -0.02384 ±0.0159, -0.00918 ± 0.0177, -0.00783 ± 0.0238, -0.01332 ± 0.0171 respectively was seen. Average heritability values for birth weight, weaning weight, 6-month body weight, 9-month body weight and 12-month bodyweight showed a change from 0.1896, 0.1552, 0.2227, 0.2086 and 0.1508 respectively to 0.2754, 0.2768, 0.1961, 0.1892 and 0.1749 respectively. Trends for all the traits were found to be significant except birthweight. Significant heritability trends were found for weaning weight and genetic trends for 6-month body weight. Our study indicates that selection may not have taken place except for 6-month body weight at the farm for the traits under study which is a matter of concern. A robust breeding program for selection of sheep on the basis of economically important traits may be the need of the hour.