Additive genetic and environmental variance components for milk traits in goat with test day model

Suzana BREŽNIK; Špela MALOVRH; Milena KOVAČ; Dušan BIRTIČ; Drago KOMPAN

doi:10.14720/aas.2000.76.1.15785

Authors

Suzana BREŽNIK Univ. of Ljubljana, Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale, Slovenia
Špela MALOVRH Univ. of Ljubljana, Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale, Slovenia
Milena KOVAČ Univ. of Ljubljana, Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale, Slovenia
Dušan BIRTIČ Univ. of Ljubljana, Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale, Slovenia
Drago KOMPAN Univ. of Ljubljana, Biotechnical Fac., Zootechnical Dept., Groblje 3, SI-1230 Domžale, Slovenia

DOI:

https://doi.org/10.14720/aas.2000.76.1.15785

Keywords:

goats, test day records, milk traits, genetic parameters, variance components, covariance components

Abstract

Genetic and environmental dispersion parameters for daily milk yield (DMY), fat (FC), protein (PC) and lactose contents (LC) were estimated on 1805 does of Alpine and Saanen breed. During the period 1991-1996, 24044 monthly test days were obtained from 57 herds in Slovenia. (Co)variance components for random effects and residual were estimated by REML using Powell’s algorithm. The models contained season (year-month interaction) and breed as fixed effects, litter size, day of lactation and parity as independent variables, and common flock, permanent environment and additive genetic effect (animal) as random effects. Heritability for DMY was 0.19 - 0.20, for FC was 0.16 - 0.18, for PC was 0.21 - 0.24, and for LC was 0.21 - 0.23. The greatest part of phenotypic variance of FC, PC and LC remained in residual. FC and PC had a negative genetic correlation with DMY (-0.32 and -0.41). Correlation between FC and PC was positive (+0.57), as between PC and LC (+0.27).