Factors Affecting Holstein Cattle Fertility Traits in the Slovak Republic

Abstract

We investigated the influence of the factors herd-year, breed-type, sire, and milk production and lactation length on the fertility traits of Holstein cattle (age at first calving, calving interval, days open, non return rate at 56, 72, and 90 day). The data were received from 87 230 Holstein cows first time calved in period 2000 and 2008 with three full-term lactations. Average age at first calving was 875 days and average milk production on first, second and third lactation was 6816 kg, 7524 kg and 6536 kg, respectively. Coefficient of determination estimated by linear model with factors as join herd-year effect and sire was 0.1164 (P<0,001) and 0.1145 (P<0,001) for variation of calving interval after 1st lactation and 2nd lactation, respectively. When the quadratic effect of milk production and lactation length was included to the linear model, coefficient of determination for calving interval variation increased significantly to 0.7049 (P<0,001) after 1st lactation and to 0.6297 (P<0,001) after 2nd lactation. Basically on these results including milk production and lactation length to the fertility genetic evaluation is needed.

Keywords

• fertility traits
• milk production
• genetic evaluation