Abstract

The analyzed population comprised 970 Polish holstein-friesian cows (PHF) and 372 Jersey cows. The database provided pedigree information on dams and their productivity. Differences between breeds in terms of longevity and culling reasons were investigated. For the group of PHF cows, the average age of culling was 5.2 years, while for Jersey cows, it was 4.81 years. In the PHF group, for the main cause of culling, about 39.5% of all cases, was classified as "other", that is unspecified causes. In the group of Jersey cows, very similar levels were recorded for four culling reasons: "sterility and reproductive system disfunction" and "infectious diseases"; each at about 17%, "low yields" at 16.5% and "metabolic disorders and diseases of the alimentary tract" at 15.6%.

Key words: Longevity, lifetime production, Jersey cows, Polish holstein-friesian cows.