The estimation of (co)variance components and genetic parameters for growth and wool traits in Harnali sheep

Abstract

The present study was undertaken to estimate (co)variance components and genetic parameters of important growth and wool traits in Harnali sheep using data records of 1862 lambs born to 144 sires and 591 dams for the period from 1998 to 2018. Six univariate animal models including or ignoring maternal genetic and permanent environmental effects were fitted to birth weight (BWT), weaning weight (WWT), 6 months weight (6WT), 12 months weight (YWT), first clip greasy fleece weight (FGFW) and annual greasy fleece weight (AGFW) and further compared using likelihood ratio test. It was observed that the model including direct additive genetic and maternal additive genetic effect without taking covariance between them into account was the most suitable for BWT and WWT. For remaining traits, only direct additive genetic effect model was found to be most appropriate. The estimates of heritability under the best model for BWT, WWT, 6WT, YWT, FGFW and AGFW were 0.23, 0.10, 0.18, 0.11, 0.08 and 0.31, respectively. The maternal influence accounted for 8 % of variation for BWT and WWT which indicated importance of maternal effect during preweaning period. The genetic and phenotypic correlations of 6WT with other traits were positive and ranged medium to moderate. Therefore, it was concluded that medium genetic variability of 6WT and its potential ability for improving other traits should be exploited to achieve genetic improvement in Harnali sheep.