The productivity of the cows during intraline selection and crossing of lines

The article provides an assessment of the productivity of the cows obtained in intraline selection and line crosses in the conditions of an industrial complex. In dairy cattle breeding, much attention is paid to the study of the effectiveness of interline crosses, which confirms the relevance of these studies.The object of the research was Holstein cows which had three or more lactations, in the amount of 249 heads, 104 of them were obtained through intraline selection, 145 heads - interline selection.According to the results of the study, it was revealed that most of the cows in the sample belonged to the lines Reflection Sovereign - 59%, and Vis Back Idiala - 38%, the Pabst Governor line accounted for 3% of the cows in the sample. The best indicators of milk yield and fat content were the first-calf heifers of the Pabst Governer line - 8517 kg of milk and 4.24%, respectively.During the third lactation, cows of the Reflection Sovering line had superior milk yield - 10,407 kg, the highest percentage of milk fat content was found in cows of the Pabst Governor line - 4.47%.When analyzing different selection methods, it was noted that fat content of milk of the cows from intraline selection was significantly more (+0.19 abs.%, P≥0.99) in comparison with the cross Reflection Sovering - Pabst Governor, and with the cross Reflection Sovering - Montvik Chieftain: fat content +0.10 abs.% and protein content - +0.06 abs.%.Thus, intraline selection should be used to increase milk productivity in the herd because the cows had the greatest productivity. Between the direct and reverse crosses, the cows of the direct cross Reflection Sovering - Vis Back Idiala had superiority significantly - in terms of fat and protein content.