Effect of gene polymorphisms on milk production of Siboney de Cuba cattle

Abstract

The objective of this study was to estimate the variance components, genetic parameters, and the individual effect of eight single nucleotide polymorphisms (SNPs) in the corresponding genes [α_S1-casein (CASA1), β-casein (BCAS), α_S2-casein (CASA2), κ-casein (KCAS), α-lactoalbumin (LAA), β-lactoglobulin (LAG), growing hormone (GH), and prolactin (PRL)] in the milk production of Siboney de Cuba cattle at 305-d of lactation.  In total, 1904 lactation records of 913 cows from 17 farms were analyzed under a repetability model. The minisequencing technique was used for uncovering the polymorphism in genes. The eight loci studied had a polymorphic behavior. The heritability and repeatability coefficients estimated for milk production were 0.12 and 0.33 at 305 days. LAG (p≤0.05) and PRL (p≤0,10) loci had a significant effect on milk production. Such coefficients were moderate, indicating that it is possible to obtain a positive response to selection in this population. The selection for both the LAG^AA and PRL^BB genotypes will result in cows having a higher milk production.

Key words: caseins, α-lactoalbumin, β-lactoglobulin, growth hormone, prolactin, heritability, milk production.