Random regression model analysis for total milk solids in first lactation dairy cattle

Abstract Text:

Total milk solids in first lactation were analyzed using random regression models, given that there were repeated measures for cows. Age (d) and days in milk were used as covariates. The additive genetic, permanent environmental and residual variance components, from which heritability was obtained, were estimated. The model containing sixth degree orthogonal Legendre polynomials best fit the data. The lowest heritability estimate was at 123 d (0.19) and the highest at 5 d (0.59). This implies greater genetic influences in early lactation, which should be an indicator of the time to select animals that are potentially the best producers of total milk solids.

Keywords:

dairy cattle

total solids

milk production