IMMUNOGENETIC CHARACTERISTICS OF UKRAINIAN SELECTIONS ORLOV TROTTER HORSES BREED
The article highlights the Ukrainian selections Orlov trotter horses breed gene pool specificity of leading breeding farms and the private sector (n = 2778). The Orlov trotter is a universal breed not only used on the racetrack, but also in classical equestrian sports, in theaters, circus, equestrian tourism, and also replenishes the hobby class horse market. In Ukraine, the Orlov trotter horses breed is the third largest, and makes up 17.9 % of the total number of breeding horses. One of the determining factors for the sustainable, progressive development of the domestic Orlov trotter population is the qualitative improvement of the breeding stock, taking into account the current conditions of their using and the prospects of progressive development, as well as their ability to respond to changing market requirements. This necessitates a comprehensive understanding about the genetic material, the essential element of which is genetic labeling using hereditary polymorphism. Each of the studied Orlov trotter populations of the domestic breeding has a unique immunogenetic profile, which is related both to breed differences and properties, and to breeding methods. Specificity and variability have been established for loci of blood group systems in Orlov trotters. A high frequency of blood group alleles is observed: Aad(0,8651 - 0,9711), Dbcm (0,1515 - 0,3059), Dcgm (0,0845 - 0,4047). Relatively rarely presented alleles: C<sup>a</sup> (0,1032 - 0,3020), K<sup>a</sup> (0,1191 - 0,3090), D<sup>ad</sup> (0,083 - 0,2323), D<sup>dg</sup> (0,0621 - 0,2738). Alleles D<sup>d</sup>, D<sup>de</sup>, D<sup>dk</sup> and D<sup>cegm</sup> in horses breed have the lowest frequency values, which range from 0 to 16 %. The polymorphic A-system of blood groups in Orlov trotter horses is characterized by high saturation of the A<sup>ad</sup> allele. C and K genetic systems are characterized by a slightly lower frequency of C<sup>a</sup> and K<sup>a</sup> alleles. Immunogenetic differences were determined and comparative characteristics of farm horses by blood groups alleles’ frequency and spectrum were performed. The high genetic diversity in the breed was found, in general, which created the basis for breeding activities for Orlov trotter’s consolidation.