The influence of the age of mother cows on the efficiency of their rearing and milk production
In the Sverdlovsk region in 2002, the Ural type of black-and-white breed was officially registered. Further, and to date, the use of purebred bulls-producers of the Holstein breed of both domestic and foreign breeding continues, which has further improved the dairy productivity and exterior indicators of the animals. Despite numerous studies, the question of the influence of the age of mothers on the productive qualities of daughters, their growth and development remains unclear to the end. The purpose of the work is to study the influence of the age of mothers of modern dairy cattle on the productive qualities of daughters. The heifers obtained from mother cows after the third lactation (third calving) had the highest live weight - 536.3± 1.93 (P≤0.05, compared with groups 1 and 2 in favor of 3). In second place were heifers from full-aged cows - mothers for the fourth calving - 520.4 ± 1.89 kg, which was less than from cows for the third calving by 13.9 kg or 2.6%, but more than heifers from young mothers for the first and second calving by 8.5 - 9.1 kg. The difference is not reliable. The highest indicators for milk yield were shown by the first heifers received from mothers at the second calving. In second place were the first heifers from mothers on the third calving. The difference between them was 275 kg or 2.7% and was not reliable. Animals from full-aged mothers had higher milk quality indicators - MJ and MDB in milk. Milk production on the farm is profitable, which is primarily due to the high productivity of animals. It is more effective to use first-calf cows for milk production, daughters received from animals at 2 and 3 calves. The profitability of milk production from them is 32.0 and 29.3%, which is 17.3-13.3 and 14.6 - 10.6% more, respectively, compared with peers from other groups.