Exterior features of different Holstein cows’ genotypes

This study presents the results of the relationship of various polymorphic variants of the GH and PIT-1 gene with the exterior in highly productive Holstein cows. Experimental animals were divided into groups depending on the combination of different allele forms of GH and PIT-1 genes. PCR method was used to determine the polymorphism of marker genes. Isolation of genomic DNA was performed using resin «Chelex-100». The reaction was carried out in a thermal cycler «Tertsyk» made by «DNA technology». The research was carried out in the Private Joint Stock Company «Agro-Soiuz» Dnipropetrovsk region. The total set sample was 48 half-sibling cows, which were the daughters of the Holstein bull Kashemir 131671771. All animals were even-aged analogues. DNA samples isolated from the peripheral blood of the experimental animals were examined. Restrictase AluI was used for the GH gene restriction. After restriction, 171 bp and 52 bp long fragments were detected in representatives of the LL genotype, and a non-restriction fragment with a length of 223 bp was found in carriers of the VV genotype. Restriction of the amplified fragment of RIT-1 gene was performed using restriction endonuclease HinfI. Fragments 660 bp, 425 bp, and 270 bp long, after processing the PCR products with HinfI restriction endonuclease, corresponded to the A allele; fragments 660 bp, 385 bp, and 270 bp long indicated the B allele. Restriction products were separated by electrophoretic method in 2% agarose gel in Tris Borate EDTA. Measurements and exterior indices studies were performed during the 2nd-3d months of the second lactation. It was found that cows of the LL / AB genotype complex compared with their peers of LV/BB and LL/BB genotypes were higher at the withers and sacrum by 3.1 and 2.9 cm, respectively (2.1 and 1.9%; at P > 0, 99). It was determined that the skin in the middle of the last rib of the LL / AB genotype cows compared to peers of LV/BB genotype was thinner by 0.5 mm (9.6%) at P > 0.95. Other measurements of the exterior in the investigated groups of animals differed little. Peers of LL/BB genotype took an intermediate position in these traits. The strength of the complex genotype influence on the features of the exterior was in the range from 2.7 to 12.6%. Holstein cows of the LL/AB genotype had a significant difference in the mass index by 3.3% at P > 0.95, as well as a slightly larger body volume by 28 134.9 cm3 (3.4%), a lower body density index by 0.037 g/cm3 (4.7%) compared with peers of the LV/BB genotype. It is proposed to select animals with the following LL/AB and LL/BB alleles in the complex genotype in order to obtain cows with a better exterior features.