DETERMINATION OF THE BREEDING VALUE OF STUDRAMS, TAKING INTO ACCOUNT THE INFLUENCE OF THE LEVEL OF FEEDING ON THE MANIFESTATION OF PRODUCTIVITY IN THEIR OFFSPRING

The article presents the results of studies that were performed on the livestock of gimmers -14 months of age of the Kharkiv intra-breed type of the precos breed. In total, 516 gimmers heads were individually registered for Origin and productivity. Among them-409 heads of offspring of 5 studrams, the breeding value of which was determined by comparing the productivity indicators of the Daughters of individual sheep with the indicators of their peers, and-with the average indicators for the herd. All offspring obtained from studrams from artificial insemination of sheep in three adjacent years were evaluated. At the same time, their cultivation took place at different levels of annual feed consumption. Statistical processing, correlation-regression, and variance analysis were performed in the SPSS-22 software environment. Studies have shown that with an increase in feed consumption by 4-6% per year, there is a likely increase in the average live weight for the herd from 6.7 to 11.6%, – by 15.1-16.1%, wool length – by 6.4–16.0 %. (p<0.001 in all cases), but this had a different effect on the disclosure of the potential of breeding traits in the offspring of individual sheep. So, if the genotype of studram No. 1823 turned out to be stable in terms of transmitting its hereditary qualities to offspring in changing conditions of providing them with food, then the genotype of studram No. 1625 and, especially, No. 1579 turned out to be plastic. In this regard, the indicators of rank correlation (R ± mr) of their score on the quality of offspring in adjacent years significantly differed and ranged from 0.600±0.462 to 0.900±0.252. in general, the indicators of feed consumption in the cultivation of offspring had reliable positive, average correlation (r) with the live weight of 0.439, clipping and wool length, respectively, 0.487 and 0.505. it is shown that the influence of genotypes of studrams (h2 ) for live weight, woolclip and coat length in their daughters was 3.0, respectively; 4.5 and 8.3% (in all cases p < 0.001), while the influence of the annual feed consumption factor was significantly greater, 17.9; 26.4 and 26.2%, respectively. The interaction of two factors (the genotype of the Ram X feed consumption) in relation to the impact on the living mass of gimmers was significantly lower, and amounted to 2.8 %, but remained probable, p< 0.05. to predict the parameters of individual characteristics of offspring productivity, appropriate mathematical models are proposed that take into account the complex influence of the genotype of the Ram and the level of feed consumption on them.