Milk Performance Traits Research Articles

Effects of marked chromosome sections on milk performance in cattle

The investigations of paternal half sibs start with the assumption that the transfer of an allele from a father to an offspring also indicates the inheritance of a distinct section of two homologous chromosomes from the father concerned. With the help of 20 gene systems, the transfers of single chromosome sections were marked and tested with regard to influences on milk performance traits. 1,457 German Friesian cattle, registered as daughters of three sires, were used. Some of the chromosome sections showed significant effects on the traits considered. Since especially those chromosomes which bear genes for milk proteins were involved, it was assumed that groups of linked loci influence the genetic variance of milk production. Possibilities for applying the results to the practical breeding situation and their significance are discussed.

Association of polymorphism harbored by tumor necrosis factor alpha gene and sex of calf with lactation performance in cattle.

In a majority of mammals, male infants have heavier body mass and grow faster than female infants. Accordingly, male offspring nursing requires a much greater maternal energy contribution to lactation. It is possible that the maternal-fetal immunoendocrine dialog plays an important role in female preparation for lactation during pregnancy. Immune system genes are an integral part of gene regulatory networks in lactation and tumor necrosis factor alpha (TNFα) is a proinflammatory cytokine that also plays an important role in normal mammary gland development. The aim of this study was to evaluate the influence of the sex of calf and/or the -824A/G polymorphism in the promoter region of TNFα gene on milk performance traits in Black Pied cattle over the course of lactation. We also studied the allele frequency differences of -824A/G variants across several cattle breeds, which were bred in different climatic conditions. The G allele frequency decreased gradually over the course of lactation events in the Black Pied dairy cattle because of a higher culling rate of cows with the G/G genotype (p<0.001). In contrast to the genotypes A/A and A/G, cows with G/G genotype showed significant variability of milk and milk fat yield subject to sex of delivered calf. Milk yield and milk fat yield were significantly higher in the case of birth of a bull calf than with a heifer calf (p<0.03). The G allele frequency varies from 48% to 58% in Grey Ukrainian and Black Pied cattle to 77% in aboriginal Yakut cattle. Our results suggest that the TNFα -824A/G gene polymorphism may have an influence on the reproductive efforts of cows over the course of lactation events depending on the sex of progeny. Allocation of resources according to sex of the calf allows optimizing the energy cost of lactation. This may be a probable reason for high G allele frequency in Yakut cattle breeding in extreme environmental conditions. Similarly, the dramatic fall in milk production after birth of a heifer calf increases the probability of culling for the cows with the G/G genotype in animal husbandry.

Effects of SNPs CAPN316 and CAST282 on quantitative characteristics of offspring produced by dairy and beef bulls

Aim. The aim of the study was to analyze effects of SNPs CAPN316 in CAST282 in calpain and calpastatin genes on offspring productive traits produced by dairy and beef bulls. Methods. Data on offspring productivity included milk performance traits (for dairy bulls), birth weight and average daily gain (for beef bulls). Molecular genetic analysis was performed by PCR-RFLP. χ²-, t-tests and Pearson correlation coefficient were used for statistical analysis at significance levels of 0.05. Results. In progeny of dairy bulls number of alleles C in both SNPs demonstrated negative correlation with milk yield (r=-0.577), fat yield (r=-0.794) and protein yield (r =-0.798). G allele of CAPN316 (“wild type”) was associated with increased number of beef bulls progeny. Body weight and average daily gain was better in GG-bulls offspring. Conclusions. C alleles of SNPs CAPN316 in CAST282 being associated with meat quality traits were found to be ineffective in selection for milk production traits.&#x0D; Keywords: calpain and calpastatin genes, SNP, CAPN316, CAST282, bull’s genotype, evaluation on progeny, offspring productivity.