Some effects on birth weight of calves and calving difficulty of cows. 2. The results of milking cattle in Hungary

The research was based on data supplied by the Department of Animal Registration and Breeding Organization of the Hungarian National Food Safety Authority. The evaluations were extended to the period of 2005-2010, and examined Hungarian Simmental and Holstein milking breeds. For the data analysis 46787 calf birth weight and calving difficulty scores of cows were available. The effect of breed of calf, age of dam at calving, year and month of birth, sex of calf and type of calving on birth weight of calves and calving difficulty score of cows were analyzed by multi-factor analysis of variance (GLM). Except the calving year in case of birth weight and calving month in case of calving difficulty score, all examined factors had a significant effect on the evaluated traits. The order of importance of the factors was as follows: type of calving, breed of calf, sex of calf, age of dam at calving, year and calving month. Hungarian Simmental calves have reached higher (P<0.01) birth weight (33.29 kg) than Holstein calves (31.24 kg). However, the calvings of Hungarian Simmental cows (1.54 points) were significantly (P<0.01) easier, than calvings of Holstein cows (1.70 points). The calves from 2 to 3 year old (first parity) cows were born with lower weight (31.77 kg) and more difficult (1.74 points), than progeny of elder cows. After four years of age of cows like in beef cattle no significant difference was found in birth weight of calves and calving difficulty score of cows. Twin calvings were more difficult with almost 0.15 points than single calvings. Their results repeatedly support the experience that with growing birth weight the risk of calving difficulty is also considerably increasing.