Estimation of genetic parameters for length of functional productive life in selected population Holstein herds in the Slovak Republic | Odhad genetických parametrov dĺžky funkčného produkčného života holštajnského plemena vo vybraných stádach v Slovenskej republike
2010
Strapáková, E., Slovenská poľnohospodárska univ. v Nitre (Slovak Republic), Fakulta agrobiológie a potravinových zdrojov, Katedra genetiky a plemenárskej biológie | Trakovická, A. | Candrák, J. | Strapák, P. | Riecka, Z.
The length of functional productive life of 8,714 Holstein cows in Slovakia (first calving from 1993 to 2008) was analysed using the Weibull proportional hazard model. The percentage of right-censored data was 24.85% for the analysed data set. Fixed effects; age at first calving, herd, lactation number, class of milk production, and change in herd size, as well as two random effects: sire and herd-year-season were included in the model. The relative risk of culling increased for low-production cows on first lactation, and for herds with decreasing size. The animals aged at first calving over 850 days showed the highest relative risk, however this effect was negligible. The variance of sires was 0.02, and herd-year-season 0.138. The heritability of the length of functional productive life was 0.053.
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