Effects of breed and casein genetic variants on protein profile in milk from Swedish Red, Danish Holstein, and Danish Jersey cows

Abstract

In selecting cows for higher milk yields and milk quality, it is important to understand how these traits are affected by the bovine genome. The major milk proteins exhibit genetic polymorphism and these genetic variants can serve as markers for milk composition, milk production traits, and technological properties of milk. The aim of this study was to investigate the relationships between casein (CN) genetic variants and detailed protein composition in Swedish and Danish dairy milk. Milk and DNA samples were collected from approximately 400 individual cows each of 3 Scandinavian dairy breeds: Swedish Red (SR), Danish Holstein (DH), and Danish Jersey (DJ). The protein profile with relative concentrations of α-lactalbumin, β-lactoglobulin, and α(S1)-, α(S2)-, κ-, and β-CN was determined for each milk sample using capillary zone electrophoresis. The genetic variants of the α(S1)- (CSN1S1), β- (CSN2), and κ-CN (CSN3) genes for each cow were determined using TaqMan SNP genotyping assays (Applied Biosystems, Foster City, CA). Univariate statistical models were used to evaluate the effects of composite genetic variants, α(S1)-β-κ-CN, on the protein profile. The 3 studied Scandinavian breeds differed from each other regarding CN genotypes, with DH and SR having similar genotype frequencies, whereas the genotype frequencies in DJ differed from the other 2 breeds. The similarities in genotype frequencies of SR and DH and differences compared with DJ were also seen in milk production traits, gross milk composition, and protein profile. Frequencies of the most common composite α(S1)-β-κ-CN genotype BB/A(2)A(2)/AA were 30% in DH and 15% in SR, and cows that had this genotype gave milk with lower relative concentrations of κ- and β-CN and higher relative concentrations of αS-CN, than the majority of the other composite genotypes in SR and DH. The effect of composite genotypes on relative concentrations of the milk proteins was not as pronounced in DJ. The present work suggests that a higher frequency of BB/A(1)A(2)/AB, together with a decrease in BB/A(2)A(2)/AA, could have positive effects on DH and SR milk regarding, for example, the processing of cheese.

Genetic analysis of Fourier transform infrared milk spectra in Danish Holstein and Danish Jersey

“…Differences in FT-IR milk-spectra between DH, and DJ have been observed, but were, in contrast with our findings, mainly caused by differences in MIR regions associated with fat (Shetty et al, 2017). Breed differences in h 2 for milk fat predicted from FT-IR milk-spectra, and milk protein predicted from FT-IR milk spectra were explained by differences in allele frequencies in major milk genes, such as DGAT1 (Maurice- Van Eijndhoven et al, 2015), and casein genes (study on DH and DJ, Gustavsson et al, 2014). For the study population of the current study, the SNP explaining most additive genetic variation for all wavenumbers was ARS-BFGL-NGS-4939.…”

“…Breed differences in milk traits have been observed, both phenotypically and genetically (Poulsen et al, 2015). Breed differences in genetics have been observed for DGAT1 (Poulsen et al, 2015) and casein genes (Gustavsson et al, 2014). However, a knowledge gap still exists regarding the genetic basis of FT-IR milk spectra.…”

A Novel SNPs in Alpha-Lactalbumin Gene Effects on Lactation Traits in Chinese Holstein Dairy Cows

“…There are significant differences in the distribution of α-LA gene polymorphisms in different bovine breeds [16,27,28]. Our direct sequencing results of Chinese Holstein α-LA gene were aligned with the sequences of three other kinds of cows [Sequence ID: AB052166 (Holstein), AB052163 (Jersey), AF249896 (Bos Taurus)] in NCBI database, indicating that the α-LA gene were significantly different between bovine breeds.…”

Characterization of the bovine milk proteome in early-lactation Holstein and Jersey breeds of dairy cows

“…The Jersey MFGM contained a higher abundance of proteins with antimicrobial and angiogenic activities, whereas the Holstein MFGM contained proteins involved in immune system modulatory processes including antioxidant, anti-apoptotic, anticancer, and host cell protection activities [24]. Breed differences in alveolar dynamics [25], feed conversion efficiency [26, 27], susceptibility to heat stress [28, 29], and genetic variants existing for protein types [30] could have contributed to the observed differences in MFGM protein profile. However, additional factors known to affect milk composition in cattle, including diet, cow health, parity, environment, management practices and stage of lactation [31-33], could have also contributed to the observed breed differences.…”