Özet:

The aim of the study was to compare the milk performance, age of first calving and inter-calving interval in Holstein-Friesian black and whites imported from Sweden with domestic cows of the same breed. We also evaluated the process of birth of tested animals and body weight of newborn calves. Domestic cows were more productive and obtained better PFC (the difference between fat and protein content) and PFR values (protein to fat ratio) in both lactations. In the first lactation, animals from Poland were characterized by better average milk yield and average protein content whereas imported cows produced higher milk yields with higher fat content (P ≤ 0.01). In the second lactation Polish cattle achieved better results in terms of average yield of proteins and fat as well as protein and fat content when compared to Swedish cows (P ≤ 0.01 and P ≤ 0.05, respectively). Heifers imported from Sweden were younger at first calving (P ≤ 0.01) and required longer inter-calving intervals. Regardless of country of origin, births were not problematic, without any complications, and calves were of similar weight.

Anahtar Kelimeler: