Abstract

RAJENDRAN, R. et al. Bayesian estimates of genetic parameters for bodyweights in Mecheri sheep of India. S. Afr. j. anim. sci. [online]. 2022, vol.52, n.2, pp.234-240. ISSN 2221-4062.  http://dx.doi.org/10.4314/sajas.v52i2.13.

An understanding of genetic information and relationships among traits is required for an improvement programme to be successful. Therefore, this study aims to estimate certain (co)variance components for bodyweights Mecheri sheep collected at various ages. The data consisted of 2 768 records that were produced by the progeny of 110 sires and 748 dams maintained in the tropical climatic conditions of Tamil Nadu, India, between 2010 and 2020. Computations of the genetic parameters were made using Bayesian methods with Gibbs sampling. The direct heritability estimates for weight at birth (BWT), weaning (WWT), 6 months (6WT), 9 months (9WT) and one year old (12WT) were 0.155, 0.262, 0.069, 0.111 and 0.067, respectively. The maternal heritabilities obtained for the pre- and post-weaning traits were low, with the mean values for BWT, WWT, 6WT, 9WT and 12WT being 0.067, 0.030, 0.036, 0.040 and 0.039, respectively. The estimates of additive genetic correlations between bodyweights at the various ages were positive and of variable magnitude ranging from 0.198 (BWT-12WT) to 0.970 (6WT-9WT). The heritability of WWT was higher than the weights at other ages, and indicated the presence of significant genetic variation in this trait. There were also high correlations between WWT and post-weaning weights. Thus, WWT, recorded early in life, could be used as a selection criterion for improving the growth traits.

Keywords : Bayesian analysis; Gibbs sampling; genetic parameters; Mecheri sheep; non-genetic factors.

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