Genetic, phenotypic and heritability trends for body weights in Kashmir Merino Sheep

Genetic and phenotypic trends of a breed indicate its progress over decades, and it is important to develop an effective futuristic selection strategy. The aim of this study was to estimate the genetic and phenotypic progress of an important synthetic sheep breed of India, Kashmir Merino. Breeding values, phenotypic averages, heritability and inbreeding coefficients were estimated for the Kashmir Merino breed for body weights at various ages reared in Government Sheep Breeding Farms (GSBF); Kralpathri (1997–2016) and GSBF, Goabal (2013–2016) for body weights of animals. Breeding value and heritability were estimated using Animal Models (Best Linear Unbiased Predictions). Trends were generated for each using R programming language. A change from 3.258 kg to 3.810 kg for birth, 21.489 to 19.660 for 6-month weights, 24.710 to 24.460 for 12-month weights was observed from 1997 to 2016. Trends obtained for phenotypic values for 6-month body weight and 12-month body weights were negative and trends for birth weight were positive. Trends obtained for breeding values for birth weight, 6-month body weight and 12-month weights were positive except for birth weight which had a negative slope. The slopes for breeding values for birth weight, 6-month weight and 12-month weights were -0.00021 ± 0.00012, 0.00068 ± 0.00045, 0.00148 ± 0.00093, respectively. Trends obtained for heritability for birth weight, 6-month weight were negative and 12-month weight were positive. The heritability slopes for birth, 6-month and 12-month body weights were 0.001912 ± 0.00180, 0.00335 ± 0.00222 and 0.00894 ± 0.00469 respectively. Trends obtained for inbreeding coefficients through linear regression found for Kashmir Merino were positive and near zero. It is concluded that an optimal selection strategy that considers both genetic merits as well as the pedigree should be adopted to sustain the sheep breeding programs in Jammu and Kashmir.