Thesis has been focused on the analysis of factors affecting gestation length in Holstein cows. It has been observed effects of month and year of fertilization in cattle, month and year of calving, parity, calf’s sex, twins and stillbirth. According to the results, it is obvious that the gestation length is influenced by many factors.

Thesis is concentrated on analysis of the various factors that affect gestation length of Holstein breed. There were also analyzed the economic aspects of gestation length in the dairy cattle. Gestation length was considerably influenced by the month of conception, sex of calves, birth of twins and parity. A significant effect was also recorded for alive and dead calves. The results show that the gestation length in cows is influenced by a number of factors which need attention.