INFLUENCE OF GENETIC FACTORS ON THE PRODUCTIVITY OF COWS
Authors: Polupan Yu. P. , Melnik Yu. F. , Biriukova О. D. 
Published: December 2019

The study was conducted on the materials of primary breeding records in the herd of Ukrainian Red-and-White dairy breed of the State Enterprise of the State Enterprise experienced farm “Khristinovske” of the Institute of animal breeding and genetics nd. a. M.V.Zubets of National Academy of Agrarian Science. The calculations were performed by the methods of mathematical statistics by means of software package "STATISTICA-12,0" on the PC. Observed matrix of observations in the format “*.sta”, which contains data on 448 variables of 1540 cows

Breeding work has provided a gradual increase in dairy productivity of the herd. The average hope for the 305 days of lactation of the firstborn herds in the last 18 years ranged from 2571 kg in 1999 calving to 7106 kg in 2015 year. The fat content of milk ranged from 3.34% (2000 year) to 4.02% (2013 year). In general, the curvilinear increase in milk yields of the firstborn in the analyzed years reaches more than 4500 kg or almost 2.8 times. The biological regularity of increase of dairy productivity of cows with age is realized. The experimental animals that were calved during the control period are the daughters of 31 boogies, belonging mainly to 12 lines and related groups and related to two (Ukrainian Red-and-White dairy and Holstein) breeds. The deterioration of the firstborn's yield in the studied herd was the Holstein breed Ingibitor EТ Red 402151, Jupy Red TV TL 114386090 and the sire of the Ukrainian Red-and-White dairy breed May 5573.

Firstborns demonstrate the realization of the genetic potential of the breed, however, with age, the influence of environmental factors leads to the elimination of intergenerational differences in productivity. In mature age cows, this advantage is offset. No qualitative milk indicators of probable unidirectional patterns of intergroup differentiation of cows of different breeds and conditional blood were found.

Belonging to a lineage or kinship group has a relatively low but significant effect on the phenotypic variability of milk yield and protein content of firstborn milk. By protein content, the influence of the specified genetic factor prolongs (even doubles) to the second lactation. The effect of linear affiliation on the live weight of heifers and cows after the first two calves, the age of the first calving and the length of time between the first two calves were statistically significant.

A statistically significant influence of linear affiliation (on average 8.3%) and paternal ancestry (13.1%) on the variability of individual signs of live weight, dairy productivity and reproductive capacity of cows was established. The influence of the father in the herd under study is 1.58 times more significant than the linear membership of the animals. Revealed a significant level of differentiation of cow groups of different lines, related groups, and half-sisters by paternal father for the first lactation.

For the firstborn, there was a tendency for curvilinear productivity increase with an increase in the conditional share of heredity in the Holstein breed. In the interspecific comparison, a statistically significant excess of the Holstein milk yields over such cows of the Ukrainian Red-and-White dairy breed (404 ± 158.0 kg, td = 2.57, P < 0.02) was established, which is leveled by the third lactation.

A significant level of differentiation of groups of cows of different lines, related groups and half-sisters by father for milk yield for the first lactation was revealed. Combining estimates of enhancing effect and phenotypic consolidation, the most desirable for further use in the herd are the prepotent enhancers Tumpy EТ Red Tl 112367468 and Michel Red 402213, and the most undesirable are the pretentious tadpill Inhibitor EТ Red 403860 and Jupy Red TV TL 114386090.