Microsatellite DNA heterozygosity and weight performance in Southern meat cattle breed heifers

The purpose of this study was to determine whether heterozygosity (assessed using microsatellite genotypes) was correlated with the body weight of heifers from birth to 18 months. The study was conducted on the heifers’ herd of the Taurian intra-breed type Southern meat cattle breed at Askaniiske State Research Enterprise (Ukraine, Kherson Region). During the study, we used ten microsatellite loci recommended by International Society for Animal Genetics (ISAG) TGLA227, BM2113, TGLA53, ETH10, SPS115, TGLA122, INRA023, BM1818, ETH3 and BM1824. The heifer’s body weight was measured at birth, at weaning, and at the age 8, 12, 15 and 18 months. Individual heterozygosity estimates (for each microsatellite loci separately) and microsatellite multilocus heterozygosity (for all used loci) estimates (MLH) were used in the analysis. ANOVA was used to determine the relationship of the dependent effects (body weight at different ages) to single locus heterozygosity using two classes: 0 (for homozygous individuals) and 1 (for heterozygous individuals). In addition, the following indicators were calculated for each genotype: the squared distances (d2) between the length of both alleles within the individual genotype for each microsatellite loci, as well as the mean squared distance (multilocus d2) between the lengths of both alleles within the individual genotype for ten microsatellite loci. Spearman’s rank correlation coefficients were used to measure the association between d2 scores (for each microsatellite loci) and body weight at different ages. The influence of different grades of estimates of MLH and mean d2 classes was also assessed based on ANOVA. Heterozygosity at locus BM2113 was significantly (P < 0.01) associated with heifer’s body weight at the age of 15 months and heterozygosity at locus BM1818 was significantly (P < 0.05) associated with heifer’s body weight at the age of 8 months. Significant Spearman’s rank correlations (P < 0.01…0.05) were also observed between the body weight and d2 score for four microsatellite loci BM2113, SPS115, ETH3 and BM1824. Individual mean heterozygosity estimates for 10 microsatellite loci and mean d2 estimates were weakly associated with weight performance in Southern meat cattle breed heifers.