Charakterystyka wskaźników produkcyjnych i reprodukcyjnych krów mieszańców F1 po czarno-białych buhajach szwedzkich (SLB) i holsztyńsko-fryzyjskich (HF) oraz oraz ich rówieśnic czarno-białych

The data of 234 lactations In 111 bw cows, 217 lactations in 118 crossbred /50% HF/ cows and 275 lactations in 135 crossbred half-blood Swedish-freslan cows were studied. The cows were used in three herds of high productivity /average yield in bw primlgravida during 305 day lactation period reached 390 kg/ in south-west Poland. Statistically significant differences in milk production traits were shown only between F₁ crossbred /HF x bw/ and their bw contemporaries /SF x bw/. The differences between crossbred /HF x bw/ and /SF x bw/ proved to be statistically insignificant. Milk yield of F₁ crossbred /SF x bw/ was higher by 13,6% in the first lactation and by 8,8% in further lactations compered to the yield obtained from bw contemporaries. The differences in fat and FCM milk yield were similar. However, no significant differences in fertility indices were found in the population of the cows studied.