Productive and biological justification of the efficiency of energy supplements in the technology of cattle growing

The purpose of the research was to study some technological aspects of increasing the productivity and reproductive qualities of cows in the conditions of the Orel region. The objectives of the study included: determination of reproductive qualities in cows of different body types establishment of milk productivity, qualitative composition and biological value of milk in cows of different body types. The object of research was cows of black-and-white breed, with a blood content of 90% or more of the Holstein breed, of various body types, aged 3-4 years, of average fatness, with a live weight of 520-650 kg, calved in the autumn period. The conditions of feeding and maintenance of experienced peers were the same. The cows were fed according to the rations adopted on the farm, taking into account milk productivity, live weight and physiological state of the animals. Zootechnical, physical, chemical and biochemical studies were carried out to realize the purpose of the study. All the studied indicators were performed according to the methods approved by the current regulatory documentation. The animals of group III were inseminated at an earlier age (551 days) compared to the animals of groups I and II (572 days, P≤0.01 and 562 days, P≤0.05). The live weight at the first insemination in cows of the I-st experimental group was 396 kg, II-nd - 405 kg and III-rd - 407 kg. The cows of the third group had a service period of 90 days, and the animals of the first and second groups had 120 and 101 days. The highest value of the coefficient of reproductive ability was observed in cows of group III, and the lowest in group I. The yield of dry matter with milk from cows of group III was the highest (1095 kg) and the animals of group I exceeded this indicator by 174 kg (P≤ 0.01), and the animals of group II - by 101 kg. According to the data obtained, it was concluded that with an increase in the overall score by body type, the content of casein, albumins and globulins in milk increased in the cows studied. In addition, a slight increase in the total amount of amino acids and an increase in its biological value were noted in the milk of the cows studied with an increase in the overall score by body type.