Genetic and phenotypic correlations between linear type traits and milk yield in Sahiwal cows

Abstract

The traits of economic importance in farm animals are mostly controlled by many gene pairs and hence show correlations. The knowledge of such correlations is very much needed while making multiple traits selection in farm animals. The present study was planned with the objectives to find out genetic and phenotypic correlations between linear type traits and milk yield in Sahiwal cows. Freshly calved 310 cows were scaled and scored for traits on a linear scale of 1-9 following the guide lines of International Committee on Animal Recording. The variance and covariance components were estimated using residuals or restricted maximum likelihood (REML) procedures. The linear mixed model was fitted for estimation of variance. Bivariate animal model analysis was performed for estimation of genetic and phenotypic correlations. Stature, angularity, rear udder height, fore teat length, dewlap width, foot angle, udder depth and rear udder width were significant sources of variation for score-day milk yield (P<0.05-P<0.001). The 305-day milk yield was influenced by linear type traits of rump angle, rump width, central ligament and rear udder width (P