LETHAL INDICATORS A HEREFORD X BLACK AND MOTLEY BULLS DEPENDING ON GENOTYPES OF GENES OF A TIREOGLOBULIN (TG5) AND A MIOSTATIN (MSTN)
Authors: Epishko O. A. , Sonich N. A. , Kuzmina T. I. , Tanana L. A. , Cheburanova E. C. , Vertinskaya O. V. 
Published: December 2018

Objective: to study the lethal indicators a Hereford x black and motley bulls depending on genotypes of genes of a tireoglobulin (TG5) and a miostatin (MSTN).
Methods: genetic, biological, and zootechnical.
Exert impact on production efficiency of production of livestock production a set of factors, one of the most considerable is genetic the potential of the animals used in breeding work. The majority of economically significant indicators such as meat efficiency have the polygenic nature and can be defined by many genes, for example, miostatin (MSTN), tireoglobulin (TG). Marker selection as an additional method can become the powerful instrument of selection selection of animals. Thus, genetic progress in achievement of a definite purpose in herd accelerates several times in comparison with traditional methods of selection. For production of meat (beef) use animals of all breeds of cattle, however most more effectively use forages and animals of highly specialized meat breeds transform them to the most high-quality meat.
Main results. As a result of research in the population bulls with MSTNBBTGTT genotypes all lethal indicators were higher in comparison with animals of genotypes of MSTNAATGCC. They surpassed animals with alternative genotypes in the mass of pair ink on 26,1 kg or 9,4% (Р < 0,01), in an exit of ink – on 3,6 items (Р < 0,05), in lethal weight – on 23,2 kg or 7,6% (Р < 0,05), in a lethal exit – on 3 items (Р < 0,05).
Bulls with MSTNABTGCT genotype also surpassed animals with MSTNAATGCC genotypes: on the mass of pair ink – on 19,5 kg or 7% (Р < 0,05), on an exit of ink - on 2,9 items (Р < 0,05), on lethal weight – on 17,5 kg or 5,7% (Р < 0,05), on a lethal exit – on 2,4 items (Р < 0,05).
On an exit of internal fat of difference between groups were insignificant and made 0,78–0,39 items (Р < 0,05).
The analysis of morphological structure of half carcasses of experimental animals showed that at slaughter in 16 monthly age hulks with higher exit of meat in comparison with peers of the first and second groups are received from bulls with a genotype of MSTNBBTGTT. So, in half carcasses of bulls with a genotype of genes of MSTNBBTGTT the content of meat was 12,7 kg more or 11,1% (Р < 0,001), in half carcasses of animals with a genotype of genes of MSTNABTGCT – on 8,1 kg or 7,1% (Р < 0,05), than at peers of the first group.
Bulls with a genotype of genes of MSTNBBTGTT surpassed the peers with a genotype of genes of MSTNAATGCC and MSTNABTGCT for 9,8% and 4,8% in meet coefficient respectively.
Conclusions. Studying of lethal indicators of experimental animals at 16 monthly age testifies to that, bull-calves with genotypes of MSTNBBTGTT exceed animals with MSTNAATGCC genotypes on the mass of pair ink, an exit of ink, a lethal exit to 26,1% (Р < 0,01), 3,6 items (Р < 0,05), 3 items (Р < 0,05). Bull-calves with genotypes of MSTNABTGCT surpassed animals with MSTNAATGCC genotypes in the mass of pair ink for 7% (Р < 0,05), in an exit of ink – on 2,9 items, in lethal weight - for 5,7% (Р < 0,05), in a lethal exit – on 2,4 items (Р < 0,05). On an exit of internal fat of difference between groups were insignificant and made 0,78–0,39% (Р < 0,05).
Studying of morphological structure of half carcasses of bulls showed that more meat hulks were received from animals with MSTNBBTGTT genotypes – in their half carcasses the content of pulp was more than 11,1% (Р < 0,001), than peers with a genotype of genes have MSTNAATGCC.