Influence of beef heifers' age on their calving course.

摘要

The aim of the study was to examine the ratio of different calving courses of Angus, Charolaise, Hereford, Limousin and Simmental beef breed cows in relation to the age at first calving as well as frequency of assisted calvings depending on the cow's age at first delivery. 6549 calvings were analyzed. The percentage of difficult deliveries, regardless of age at first calving, was low and amounted to 5.6%. A highly significant dependence between first calving age and its course was noticed. The most assisted deliveries were observed in the group of cows delivering the first calf up to 25 months of age. The cow's breed statistically had a highly significant influence on calving course: The lowest ratio of assisted deliveries was noticed for Simmental and Angus cows, the most for Charolaise and Limousin cows. In case of Angus, Hereford and Limousine breeds there was no statistically significant relationship between age at first calving and its course. Taking into consideration the influence of age of first calving on its course, it should be stated that there are not any contraindications for primiparous cows of Angus, Hereford and Limousine breeds to deliver for the first time at 2 years of age.