Multi-trait bayesian analysis and genetic parameter estimates in production characters of Mecheri sheep of India

Abstract

The present study was conducted to calculate the genetic parameters for direct and maternal influences on Mecheri sheep growth features by Bayesian analysis using multi-trait animal model for designing suitable breeding application and genetic assessment methodologies. The genetic determinants for varying body weights at different ages were calculated using data from 2825 Mecheri lambs born between 2010 and 2020 that were kept in a warm and semi-arid climate. Mecheri sheep body weight (mean ± SE) at various stages viz., BW, WW and BW12 were 2.6 ± 0.01, 11.1 ± 0.05 and 20.7 ± 0.13 kg respectively. The direct estimates of heritability (± SD) for BW, WW, BW6 and BW12 were 0.21 ± 0.041, 0.21 ± 0.041, 0.12 ± 0.052 and 0.13 ± 0.053 respectively and the maternal heritability for BW, WW, BW6 and BW12 was 0.18 ± 0.021, 0.08 ± 0.023, 0.11 ± 0.022 and 0.13 ± 0.033, respectively. Estimates of maternal heritability suggests that even at later stages, there were considerable maternal effects. For several growth traits, positive estimates of additive genetic connections were observed, with values ranging from low to high. The additive genetic correlation between WW and BW6, BW9 and BW12 was 0.70 ± 0.145, 0.57 ± 0.171 and 0.50 ± 0.194. The maternal genetic correlations ranged from 0.06 ± 0.152 (BW-BW12) to 0.86 ± 0.046 (BW6-BW9) and the residual correlation increased progressively from 0.18 ± 0.034 (BW-WW) to 0.85 ± 0.013 (BW9-BW12). The medium to high estimates of heritability and genetic correlation of body weight parameters at various ages in Mecheri sheep indicated the genetic potential for all traits. In general, the features WW and BW6 both refer to the same genetic growth process, hence, it is recommended to undertake single trait selection based on weight at weaning age rather than using the present selection procedure of weight at six-month of age. By choosing the top performers from the Mecheri sheep flocks, it is possible to take advantage of the strong genetic potential for improvement in these parameters.