Influence of bulls on the results of calving of their daughters

Improving the reproductive qualities of cows is one of the modern problems of domestic breeding. The scientific article examines certain issues of assessing the reproductive qualities of dairy cattle. The research was carried out in one of the farms in the Orel region. A retrospective analysis of the calving results in the herd was used, including an analysis of the pedigrees of the dairy cows. To clarify the origin of the breeding sires, official sources were used, including the Alta Genetics Russia website and the Orlovsky Kolos subsidiary farm. The studies showed that the fathers in the pedigrees of the cows belonged to the lines Annas Adema 30587, Wis Back Ideal 1013415, Reflection Sovereign 198998, Seiling Triune Rocket 252803, Montvik Chieftain 95679, etc. It was established that the daughters of the sire Don 1919 (104 calvings) did not produce twin calves or stillborn calves. In the daughters of the sire Emir 35, it was found that out of 175 born calves obtained from his daughters, 14.6% of the heads were twins, but 4.6% of the calves were born dead, including twins. Sire Proudy 51, as the father of cow mothers, contributed to the fact that out of 29 calves received, 8 were dead (this amounted to 27.6% of the number of calves born). In total, 27 twins and 41 dead calves were treated in the herd studied. The correlation between the number of twins and the number of stillborn calves was r=0.524. Based on the results of the research, it was concluded that preference should be given to those sires that contribute to the ease of calving and, accordingly, the absence of stillborn calves. The presence of twins in dairy cows should also not be a priority in breeding and selection for reproductive qualities.