mixed linear models repeated measures fixed regression genetic parameters
Institute of Mathematics and Informatics Bulgarian Academy of Sciences
Pliska Studia Mathematica Bulgarica, Vol. 17, No 1, (2005), 313p-322p
Multivariate and univariate lactation models were applied to test day data to predict genetic value of daily milk yield of a sample of Black and White cows. The models for genetic evaluation include a set of fixed main effects, fixed regression on functions of days im milk, random effects of permanent environment within lactation, random additive genetic effect and residual effect. Under multivariate model for daily milk yield test day records within lactation are considered as repeated measurements, and different lactations are treated as separate traits. Univariate model is applied for each lactation using test day yield as repeated measure. The variance components, genetic parameters and ranging of the animals through the multivariate and univariate metod were compared.