OPTIMIZATION OF DIAGNOSTIC METHODS OF HH6 FERTILITY HAPLOTYPE CARRIERS IN HOLSTEIN COWS AND ITS PREVALENCE

Abstract

The contributors optimized molecular genetic methods for diagnosing carriers of the HH6 fertility haplotype in Holstein cows of the Mezhdurechensk AGRO LLP located in the Ile district of the Almaty region and studied the prevalence of the HH6 fertility haplotype in 150 cows of foreign selection. The results of specialized foreign literature review allowed to identify genetic nature of the HH6 fertility haplotype, which appeared as a result of a point mutation in the coding part of the SDE2 gene (g.29773628 A> G SNP, GTCTCCGCC[A> G]TCTCACCCAGT). Therefore, the classical PCR-RFLP analysis method was used to diagnose heterozygous carriers of the HH6 fertility haplotype mutation in cows. Identification of the wild and mutant types of the SDE2 gene allele was carried out by restriction of the PCR product with BccI endonuclease with the CCATC(N) restriction site. On the electrophoregram of homozygous healthy animals after restriction with BccI endonuclease due to the presence of the restriction site, two fragments were found: 278 bp and 246 bp, in heterozygous carriers three fragments: 524 bp, 278 bp and 246 bp. As an alternative diagnostic method, the KASP method was used and in healthy homozygous individual animals, one 88 bp fragment was found on the electrophoregram. Of the 150 Holstein cows tested, 7 heterozygous carriers of the HH6 fertility haplotype were identified and the prevalence of this genetic defect in the tested animals was 4.67%.