STUDY OF THE INFLUENCE OF THE РIT-1 GENE GENOTYPE ON INDICATORS OF MILK PRODUCTIVITY IN COWS

Abstract

Scientists see measures based on marker-associated selection as a promising direction of use in practical selection work. This makes it possible to select animals based on the assessment of their genotype and to reduce the influence of the external environment. A particularly important factor in the use of marker-associated selection in dairy farming is a significant acceleration of the selection effect. Scientific studies on the influence of the RIT-1 gene on the indicators of milk productivity of first-born cows were carried out on the basis of two breeding plants for the breeding of Ukrainian brown dairy and Ukrainian black-spotted dairy breeds, which belong to the State Enterprise "Experimental Farm of the Institute of Agriculture of the Northeast of the National Academy of Agrarian of Sciences of Ukraine", located in the Sumy district. The polymorphism of the pituitary-specific transcription factor PIT-1 gene was studied in the genetic laboratory of the Institute of Animal Husbandry according to generally accepted methods. Milk productivity was assessed by monthly control milkings with milk sampling. A counter – indicator IU-1 was used to take milk samples. The content of milk components was determined in the laboratory of the Institute of Animal Husbandry of the National Academy of Sciences by the method of infrared photometry on the equipment of the corporation "Bentley Instruments" (USA). Among the studied animals of both breeds, no cows with the AA genotype were found. The majority of black and spotted first-borns had heterozygous AB genotype, brown ones – homozygous BB. The conducted studies proved the superiority in terms of milk yield of cows of the Ukrainian black and spotted dairy breed with the AB genotype, and cows of the Ukrainian brown dairy breed with the BB genotype. First-borns with the heterozygous AB genotype differed in the higher content of fat and protein in the milk of animals of both studied breeds. According to the average content of dry matter, animals with the heterozygous AB genotype predominated among the black-spotted firstlings, and among the bulls – with the homozygous BB genotype. According to the average content of dry skimmed milk residue in the milk of animals of both experimental breeds, firstborns with the homozygous BB genotype prevailed.