In the course of the research conducted at Agro-Soyuz LLC (Kabardino-Balkarian Republic, Chegemsky district), the goal was to study the productivity of 69 first-calf cows of the Gomitinsky black-andwhite breed, the daughters of three breeding bulls, depending on the forms of inheritance or the leading breeding characteristics of dairy productivity (milk yield, fat content), for the definitions of which were used by a new methodology, which is a modified version of the methodology widely used in breeding work with dairy cattle.As a result of determining the forms of inheritance of milk yield in experimental first-calf cows, it was found that the largest share among them fell on animals with milk yield due to such a form of inheritance as regression of the mother (44.9%), the smallest share – on first-calf cows with milk yield due to the dominance of the father (7.3%). When determining the forms of inheritance of fat milk, the same trend was observed as when determining the forms of inheritance of milk yield, that is, among 659 first-heifer cows, the most animals were from the mother regression group (42%), and the least were animals from the father dominance group (4,4%). The established difference between groups of first-calf cows with different forms of inheritance of the breeding trait turned out to be quite significant and reached, in some cases, 2368 kg in milk yield per lactation (p>0,999), 0,32% in fat content (p>0,99).

The problems of adaptation of a highly productive Holstein breed to new natural and climatic conditions and using their productive qualities are relevant. In order to study the influence of paratypical factors on the productive characteristics of Holstein cows, productive qualities of Holstein cows and their paternal half-sisters brought from the USA were compared. It has been established that during their first, second and third lactation periods, Holstein cows had better milk yield parameters than their paternal half-sisters brought from the USA. In Holstein cows, values of repeatability and heritability of milk yield parameters were higher than in their half-sisters. The influence of the “Region of reproduction” factor was observed for the milk yield per lactation. To the least extent, it was observed for the mass fraction of protein. The highest frequency, heritability, and factoriality of milk yield parameters were observed in Pilot’s daughters.

No abstract

The article studies the influence of the frequency and time of consumption of colostrum on the immunobiological reactivity of lambs obtained from mothers of the same age, selected according to the principle of analogues. It has been established that first lambers (9–16 months) with intensive rearing and abundant feeding have an average level of resistance of the organism and its indicators are characterized by stability. The offspring obtained from these first lambers (experimental group) in terms of the level of immune parameters are not inferior to their peers obtained from the ewes of the control group. Lambs from first lambers in terms of lysozyme activity of blood serum, immunoglobulin content are superior to their peers from older ewes (the difference is not statistically significant, P> 0.05). At the same time, young animals regardless of the age of their mothers have the same vitality. The lambs' mortality from birth to wean in the experimental and control groups was approximately the same - 7.2 and 8.0%, respectively.

No abstract