No abstract

No abstract

No abstract

The research goal is to increase the duration of the period of productive use of cows in modern complexes for milk production. The object of research is cows of the newly created intra-breed middle Volga type of black-and-white breed, culled for various reasons from the herd in the period from 2016 to 2018. All animals for further statistical processing of the studied indicators were divided into four groups, taking into account the type of stress resistance according to the method of E. p. Kokorina in the modification described by E. N. Letyagina. It was found that all hematological indicators decrease with increasing stress resistance in cows, except for the content of white blood cells. An increase in the concentration of white blood cells in the blood by 6.8-41.9% is probably a protective reaction of the body. Different reactivity of cows to the action of stress factors has an impact on the natural resistance of their body. A decrease in BASC by 3.2-10.5% was found, LASC – by 3.5-9.0%, FUNK-by 1.8-7.3%. When stress resistance decreases, the concentration of immunoglobulins in the blood decreases: IgG-by 3.9 – 11.2%, IgM-by 1.1 – 22.5%, IgA-by 3.4 – 24.1%. Studies have shown that cows of the first type of stress was superior to their peers with high stress-STU life expectancy at 262,6-1264,8 day (11,6-100%; P<0,05-0,001); in the long-STI period of productive use – on 0,2-2,5 lactation (4,7-125%; P<0.001); the magnitude of the average milk yield per lactation on 487-2175 kg of milk (8,5-53.6 percent; P<0,05-0,001); the value of lifetime milk yield – for 3340-19924 kg of milk (13.5-245.5%; P<0.01-0.001); for milk yield per 1 day of life-0.2-4.7 kg (1,8-73,4%; P<0,001), on the 1st day of lactation – 2,3-5,5 kg (13,9-41,4%; P<0,001). It is recommended that the" breeding core " of the herd be equipped with animals of types I and II of stress resistance. When using type II stress resistance cows, additional attention should be paid to the milk productivity of their mothers when selecting breeding bulls.

The article presents the results of research confirming the influence of intensive technologies used in modern dairy complexes on the level of reproduction and productivity of milking herds. It is noted that when heifers are bred intensively in the specialized farm, at the first successful insemination the animals reach a high live weight (350-360 kg) at the age of 330-340 days. A high efficiency of intensive technology of dairy herd reproduction using sexed semen has been established. Thus, the pregnancy rate of heifers from the first insemination was 61.5% and that of cows of the first lactation, taking into account their health condition and the diseases they had undergone, was 41.1%. During calving, 82.9 - 94.3% of replacement heifers were obtained from the control stock of heifers and cows of the first lactation. Researches have shown that intensive technologies of the maintenance, feeding and reproduction herd realized on modern dairy complex provide high milk productivity of animals (the level of milk yield 10,240 kg of milk, mass fraction of fat in milk - 3.98% and that of protein - 3.17%). In the herd more than 3% of animals completed the sixth lactation (the level of milk yield - 9,940 kg of milk, the mass fraction of fat in milk - 4.35% and protein - 3.2%), which demonstrates the prospects of forming the dairy herd with a long period of economic use of cows. Consequently, intensive milk production technologies in modern complexes contribute to the increase of productivity of young cattle and milking cows, ensure high efficiency of reproduction of the dairy herd and, to a certain extent, increase the duration of productive use of animals.