Reproductive qualities and milk productivity of black-and-white cows depending on sire lineage

Abstract

The paper presents the results of studying the effect of sire lineage on reproductive qualities and milk yield of cows. The study was carried out inIrkutskregion on a herd of Holsteinized black-andwhite cattle of Pribaikalsky type. The analysis of the main characteristics of reproductive capacity of herd cows on a farm was performed during 2013–2018. The material of the research work was based on the informational database of animals from the program of breeding register Selex. Cows were divided according to sire lineage and milk productivity into five groups by the level of milk yield: from 5000 to6500 kg, 6501-8000, 8001-9500, 9501-11000 and more than11001 kg. Successful insemination of heifers took place at the age of 15.7-16.6 months with the live weight of more than400 kg, which corresponds to zootechnical standards. The earliest (15.7 months) insemination was in heifers of Reflection Sovereign sire line, the age of first calving was 753 days with the live weight of561 kg. The latest (498 days) successful insemination was observed in heifers of Montvik Chieftain bull line with the live weight of498 kg. Cows of Sealing Trygen Rocket (8766 kg) and Reflection Sovereign (8704 kg) sire lines had the highest milk productivity with a significant difference (p ≥ 0.90). The cows of these lines had the longest service period (164 and 179 days), as well as the length of the calving interval (445 and 458 days), respectively. The coefficient of reproductive capacity of cows of different sire lines ranged from 0.80 to 0.88, which is a low indicator.