Genetic Evaluation of Growth Rate and Kleiber's Ratio Traits in Deccani Sheep Using Bayesian Inference

The present study aimed to estimate the contributions of direct additive and maternal genetic effects on growth rate and Kleiber's ratio traits in Deccani sheep. Data from 2590 lambs born between 2011 and 2020 at the ICAR-Network Project on Sheep (Deccani) Improvement, Maharashtra, India, were utilised. Growth traits were assessed as average daily gain from birth to weaning (ADG1), weaning to 6 months (ADG2), and 6 to 12 months of age (ADG3), along with the corresponding Kleiber's ratios (KR1, KR2, and KR3). Bayesian inference was employed to estimate (co)variance components and genetic parameters by fitting animal models that included direct additive and maternal genetic effects, as well as significant fixed effects, using BLUPF90 programs. Estimates of direct heritability for ADG1, ADG2, ADG3, KR1, KR2, and KR3 were 0.07 ± 0.04, 0.05 ± 0.03, 0.08 ± 0.07, 0.03 ± 0.01, 0.04 ± 0.01, and 0.12 ± 0.06, respectively. Maternal genetic and permanent environmental effects accounted for up to 9% and 4% of the total phenotypic variance in the studied traits. A negative genetic correlation between direct additive and maternal genetic effects indicated an antagonistic relationship, whereas positive genetic correlations were observed among the growth and Kleiber's ratio traits. The study results suggested that although additive genetic variation for these traits is low, incorporating maternal effects in selection strategies could enhance growth performance in Deccani sheep populations.