Genetic evaluation of the length of productive life in Holstein cattle in the Czech Republic
Pachova, E.(Vyzkumny Ustav Zivocisne Vyroby, Prague (Czech Republic))E-mail:eva.007@centrum.cz | Zavadilova, L. | Soelkner, J.
Survival Kit V3.12 was used to analyse the length of productive life of 230,028 Holstein cows in the Czech Republic. The model included parity x stage of lactation interaction, herd x year x season interaction, class of milk production within herd and year, breed within years and the time-independent effect of age at first calving and the random effect of sire. The highest risk of culling was found for cows at the beginning of the first lactation and at the end of all lactations. The risk of culling of cows assigned to the lowest milk production class was five times higher than that of cows assigned to the average milk production class. It decreased with parity, age at first calving and decreasing percentage of Holstein breed. Breeding values for sires expressed as a risk ratio of their daughters varied between 0.7 and 1.45. Estimated heritability of longevity was 0.025 on the log scale and 0.041 on the original scale.
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