SIGNS OF POSTEMBRYONAL DEVELOPMENT YOUNG PIGS OF DIFFERENT GENOTYPES BY MELANOCORTIN 4 (MC4R) RECEPTOR GENE AND THEIR PRODUCTIVITY

The results of studies of indicators of individual development, fattening, and meat qualities of young pigs of the large white breed of different genotypes according to the melanocortin receptor 4 (Mc4r) gene are presented, and the level of correlations between traits is calculated, as well as the economic efficiency of the use of animals in experimental groups. The research was carried out in agricultural formations of the Dnipropetrovsk region (Ltd. «Druzhba-Kaznacheivka»), the meat processing plant «Jazz», the laboratory of the genetics of the Institute of Pig Breeding and APP of the National Academy of Sciences, and the laboratory of animal husbandry of the State Institution «Institute of Grain Crops of the National Academy of Sciences». The work was carried out following the scientific research program of the National Academy of Sciences No. 30, «Innovative technologies of breeding, industrial and organic production of pig farming products» («Pig farming»). Assessment of animals according to growth indicators in early ontogenesis, fattening, and meat qualities were carried out taking into account the following characteristics: live weight at the time of birth, at the age of 3 and 6 months (kg), average daily increase in live weight during the period of control fattening, g; the age of reaching 100 kg live weight, days, length of a chilled carcass, cm; length of the bacon half of the cooled carcass, cm; thickness of lard at the level of 6-7 thoracic vertebrae, mm. The «intensity of formation» index (Δt; age periods 0-3-6) was calculated according to the method of Svichin (1985). Biometric processing of research results and calculation of the economic efficiency of research results was carried out according to generally accepted methods. It was established that according to live weight at 3 and 6 months of age, fattening and meat qualities (age of reaching a live weight of 100 kg, days; lard thickness at the level of 6-7 thoracic vertebrae, mm; length of the chilled carcass, cm) young pigs the population under control belongs to the I class and the elite class. Young pigs of the Mc4r AG genotype outperform peers of the Mc4r AA genotype in terms of average daily live weight gain, age at which live weight is 100 kg, lard thickness at the level of 6-7 thoracic vertebrae, and chilled carcass length by an average of 4.50 %. According to the Tyler B. index, the difference between the groups is 11.82 points (td=3.70; P<0.01). The intra-breed differentiation of young pigs according to the «formation intensity» index (Δt; age periods 0-3-6) shows that the difference between the animals of the III and I experimental groups in terms of the average daily increase in live weight is 6.65 %, the age of reaching the live weight of 100 kg - 3.77 %, the thickness of lard at the level of 6-7 thoracic vertebrae - 0.98% and the length of the chilled carcass - 1.13 %. The number of reliable correlations between fattening and meat qualities, the «formation intensity» index (Δt; age periods 0-3-6), and Tyler B. index is 75.0%, which indicates the possibility of their use in breeding tribal work. The use of young pigs of the genotype Mc4r AG and animals of the III group, in which the index «intensity of formation» (Δt; age periods 0-3-6) ranges from 0.715 to 0.947 provides additional production at the level of +2.71 - + 4.77 %, respectively.