Phenotypic and genetic trends of body weights in corriedale sheep under temperate conditions

Sheep is an important genetic resource of Jammu and Kashmir, India. Corriedale sheep was imported for improving the production potential of sheep maintained at Sher-e-Kashmir University of Agricultural Sciences and Technology of Kashmir (SKUAST-K). A study was undertaken to study the heritability, phenotypic, and genetic trends of Corriedale sheep over the years under temperate conditions. Data from 1969 to 2016 were collected for body weights at birth, weaning, 6, 9 and 12 months of age. Mean phenotypic values, heritability and estimated breeding value (EBV) estimates by BLUP animal model were used for regression on the birth year to estimate trends over four decades. Adecline in body weights from 16.71 to 12.78 kg for weaning, 21.03 to 15.26 kg for 6 months, 24.09 to 18.21 kg for 9 months and 28.34 to 21.12 kg for 12months was observed from 1969 to 2016 in Corriedale sheep. Average heritability values for body weight at birth, weaning, 6, 9 and 12 months showed a change from 0.19±0.01, 0.16±0.01, 0.22±0.02, 0.21±0.01 and 0.15±0.01 to 0.28±0.01, 0.28±0.01, 0.20±0.01, 0.19±0.01 and 0.18±0.01, respectively. Change in EBVs for body weight at birth, weaning, 6, 9 and 12 months from 0.0021±0.0067, -0.0011±0.0093, -0.0020±0.0138, 0.0067±0.0130, -0.0006±0.0078 to 0.0010±0.0070, -0.0238±0.0159,-0.0092±0.0177, -0.0078±0.0238, -0.0133±0.0171, respectively were observed. Phenotypic trends for all the traits were significant (P<0.01) except for birth weight. Heritability trends were significant (P<0.05) for weaning weight and genetic trends for 6 month body weight. It was observed that selection may not have taken place except for body weight at 6 months which is a matter of concern. A robust breeding programme for selection of sheep on the basis of economically important traits may be framed.