Associations Between Milk Protein Polymorphism and First Lactation Milk Production Traits in Finnish Ayrshire Cows

Abstract

Genotypic effects of beta-casein (CN), kappa-CN, and beta-lactoglobulin (LG) on milk, fat, and protein production and fat and protein percentages were estimated for 18,686 Finnish Ayrshire cows in first lactation using an animal model. Casein genotype effects were estimated including individual beta-CN and kappa-CN simultaneously in a model and then as composite beta-kappa-CN. The A2 allele of beta-CN and the A allele of kappa-CN, as well as the A1 allele of beta-CN and the B or E allele of kappa-CN, appeared together more frequently than was expected. Because of linkage disequilibrium in the casein loci and, consequently, unbalanced data, some contradictory effects of casein genotypes were obtained with the two models. A well-founded way to estimate the effects of casein genotypes was to use beta-kappa-CN genotypes. Composite casein genotypes including the A2 allele of beta-CN were associated with the highest milk and protein production and the lowest fat content, those including the B allele of kappa-CN with the highest protein content, and those including the E allele of kappa-CN with the lowest protein content. The effect of the beta-kappa-CN genotypes on protein content was moderately strong, and the effect was somewhat smaller for other traits. The AA genotype of beta-LG had a favorable effect on milk and protein production, and the BB genotype had a favorable effect on fat content.

Joint effects of CSN3 and LGB genes on milk quality and coagulation properties in Czech Fleckvieh

“…High yield characteristics were also associated with genotypes BBAA, AABB and AAAB. This is in agreement with Ikonen et al (1999b), who found that CSN3 alleles E and A increase milk yield but decrease protein content. The highest protein content was found in the genotype combinations BBAA, ABBB and ABAB, which illustrates the effect of CSN3 allele B on increasing protein content (Ikonen et al, 1999b;Kučerová et al, 2006).…”

“…This is in agreement with Ikonen et al (1999b), who found that CSN3 alleles E and A increase milk yield but decrease protein content. The highest protein content was found in the genotype combinations BBAA, ABBB and ABAB, which illustrates the effect of CSN3 allele B on increasing protein content (Ikonen et al, 1999b;Kučerová et al, 2006). Similarly, Kaminski et al (2002) reported the highest protein content as well as fat content associated with genotype combinations ABBB and ABAB.…”

QTL mapping in outbred half-sib families using Bayesian model selection

“…For the first extra QTL, the position estimates were close to the marker ILSTS97, which was also reported by Moisio et al (2000) to affect the PP trait. For the second, the estimated position was close to CSN3 and CSN1, as reported by many researchers (Velmala et al, 1995;Maki-Tanila et al, 1998;Leone et al, 1998;Ikonen et al, 1999), and also close to AFR227, as reported by Velmala et al (1999), and to BP7, as reported by Ashwell et al (1998) and Schnabel et al (2005), all of which were found to affect the PP trait. The variance component model can be written as…”

Influence of composite κ-casein and β-lactoglobulin genotypes on composition, rennetability and heat stability of milk of cows of Slovak Pied breed

“…A positive effect of κ-CN B and β-Lg B alleles on the protein content was also reported by Ikonen et al (1999) and Miceikiene et al (2005). It was proved that A variant of β-Lg compared to B variant had higher protein (Ng-Kwai-Hang, 1998) and fat contents.…”

“…The effect of the κ-CN/β-Lg variants and herd on milk composition and technological properties of milk (GLM analysis) (Chrenek et al, 1998;Ng-Kwai-Hang, 1998;Ikonen et al, 1999;Miceikiene et al, 2005). Our results agree with these conclusions.…”