The Effect of rearing and age at first calving on the performance and longevity of Holstein dairy cattle

This thesis examines the influence of the level of rearing and age at first calving on performance and longevity of Holstein dairy cattle in the company ZD Krásná Hora nad Vltavou C. The quantity of milk per kg in the first lactation, functional longevity in kg of milk, functional longevity and longevity in days belong among the indicators observed by cows of Holstein cattle. The results of the monitored herds can be concluded that extension of age at first calving is statistically significant on the amount of milk in the first lactation, on functional longevity in kg of milk, on functional longevity and longevity in days. In contrast, no significant influence of the weight was elicited by observed indicators. The highest longevity in the monitored herd was achieved by the cows that were excluded for a difficult birth and also achieved the highest milk yield for functional longevity in kg milk and observation for the highest average in the number of lactations for life