ASSOCIATION OF CSN3 GENOTYPES WITH THE DEVELOPMENT OF LIVE WEIGHT IN REPLACEMENT YOUNG CATTLES OF THE BREED

The frequency of occurrence of CSN3 genotypes and their association with body weight at birth, at the age of 6, 10, 12, 18 months and at the 1st insemination in repair young animals was studied. The study showed that the frequency of occurrence of genotype CSN3 was 53.1%, genotype CSN3 – 35.7%, genotype CSN3 – 11.2%. An analysis of the association of CSN3 genotypes with live weight indicators showed that despite the fact that the repair young of the Kholmogorsky CSN3 breed had a significantly higher live weight at birth than their peers with CSN3, the opposite situation was subsequently observed between animals with the same genotypes in terms of live weight at the ages of 6 and 10 months. Also, a significant superiority of young CSN3 over their peers with the CSN3 genotype was observed in terms of weight at the age of 10, 12, 18, and at the 1st insemination. In addition, a significant superiority in the development of live weight at the time of the 1st insemination was revealed in the repair young with CSN3 relative to the young with CSN3. Thus, individuals with CSN3 gain live weight better in the prenatal period of development, taking more biological resources from maternal cows during pregnancy, and then they lose weight gain in the postnatal period to animals with CSN3 and CSN3 genotypes. It follows from this that young animals with the CSN3 and CSN3 genotypes have greater growth energy and are predisposed to faster weight gain necessary for the 1st insemination and increased productivity during the first and subsequent lactation. Thus, we conclude that the CSN3 allele has an effect on the rate of weight gain in the repair young.