The paper presents results of studies on the effects of SNPs L127V, F279Y, A257G, CAPN316, CAST282 and C994G in GH, GHR, CAPN1, CAST and CYP3A28 genes on individual animal growth parameters and reproductive performance characteristics in Aberdeen-Angus breed at both individual and population levels.
The cows were analyzed to reveal the constitution parameters, body weight dynamics, reproductive performance parameters and lactation characteristics by calf growth rate. The inbreeding coefficients FIS, FIT and FST and linkage disequilibrium in terms of D’ and r2 were calculated based on allele and genotype frequencies. Cluster analysis was performed based on the Nei’s distance between populations to evaluate microevolutionary processes. Microscopic analysis of forages from storage was performed to determine quantitative and qualitative composition of mycotoxin producing micromycetes.
A positive correlation of wild-type alleles with the key body parameters was established: C-allele of SNP L127V with the size of the sacrum, r=0.94, udder, r=0.93 and the total score, r= 0.91; T-allele of SNP F279Y with musculature, r=0.97 and udder, r=0.99. Cows with ССТТ-genotype for SNPs L127V and F279Y had udder 9% larger than cows with other genotypes and the total score 8% higher. A positive effect of the C-allele of SNP CAST282 on the musculature size was demonstrated, r=0.99, while the allele G of both SNPs correlated positively with the body composition, r=0.78.
The best genotype for SNPs L127V and F279Y according to the productive selection of cows was CCTT. The genotypes CC of SNP CAPN316 and CG of SNP CAST282 were advantageous in relation to the body weight dynamics; after the age of two years differences from other genotypes had reached 40-50 kg or 9-10% and 20-50 kg or 7-13%. The highest growth rate was found in cows with the combined genotype CCCG for SNPs CAPN316 and CAST282.
While assessing cows’ reproductive function, the C-alleles for SNPs C994G and L127V were associated with a lower age of first calving – 78.5±36.0 days and 50.7±45.2 days, with an average age of first calving being 966.8±26.1 days. The cumulative effect of wild-type alleles for SNPs L127V (C), F279Y (T) and A257G (A) was associated with a decrease in the calving interval by 30-35 days. Cow lactation rates estimated by calf growth were associated with SNPs in GH and GHR genes: C-allele of SNP L127V had a positive effect on calf birth weight by +0.5±0.3 kg and bulls weight at 15 months by +15.6±9.0 kg, alleles T and A for SNPs F279Y and A257G were associated with a change in heifers’ and bulls’ average daily gain by -14.5±6.7 g and 29.4±12.7 g and weaning weight by -3.2±1, 4 kg and 5.3±2.7 kg. According to the regression analysis results, the combined effect of C994G and season on birth weight was +0.45±0.22 kg.
The frequencies of genotypes for the SNPs were: for GH gene SNP L127V: CC=10%, CG=48%, GG=42%; for GHR gene SNP F279Y: TT=62%, TA=11%, AA=27%; SNP A257G: AA=73%, AG=25%, GG=2%; for CYP3A28 gene SNP C994G: CC=36%, CG=33%, GG=31%; for CAPN1 gene SNP CANP316: CC=14%, CG=54%, GG=32%; for CAST gene SNP CAST282: CC=59%, CG=38%, GG=3%.
According to SNPs L127V, A257G, CAPN316 and CAST282, the sample under study was in Hardy-Weinberg equilibrium. The negative effect of the inbreeding level in SNP L127V on the calf birth was -6.4±1.8 kg and on the calf average daily gain was -97.93±29.89 g. High value of the inbreeding coefficient FST for SNPs CAPN316, CAST282 and F279Y negatively correlated with body weight before 15 months and were
-113.0±16.8 kg, -91.3±7.4 kg and -64.3±13.9 kg. Found absence of linkage disequilibrium (D’=0,11 and r2=0,004) within GHR gene at the distance of 18 kb is attributed to relatively high inbreeding coefficient value – FST ≤16.1%.
It was shown that the frequency of the C-allele in SNP L127V correlated with the size of the animal body in different breeds, r=0.93, and was influenced by climatic and geographical factors depending on the distance to the equator. The correlation between the T-allele of SNP F279Y and milk yield was established in dairy breeds, r=-0.713. The allelic frequency of SNPs CAPN316 and CAST282 demonstrated the isolation of the Ukrainian Aberdeen-Angus sample in the structure of world breeds and greater contribution of “geographical region” factor over the “breed”.
