Effect of the kappa-casein gene polymorphism, breed and seasonality on physicochemical characteristics, composition and stability of bovine milk

Abstract

-The objective of this study was to evaluate the effect of genetic polymorphism of kappa-casein, breed and seasonality on the physicochemical characteristics, composition and stability of milk in commercial dairy herds. A total of 879 milk and blood samples were collected from 603 Holstein and 276 Girolando cows, obtained during rainy and dry seasons. Milk samples were analyzed to determine the physicochemical characteristics, composition and ethanol stability, while blood samples were subjected to polymerase chain reaction to identify the kappa-casein genotype. The frequencies of genotypes AA, AB and BB of k-casein were respectively, 66.83, 31.84 and 1.33% for Holstein, and 71.38, 27.90 and 0.72% for the Girolando cows, respectively. The A allele was more frequent than the B allele, both for Holstein (0.827 and 0.173) and Girolando cows (0.853 and 0.147), respectively. Cows of AB and BB genotypes showed a higher milk fat content compared to the AA genotype. There was an interaction between breed and seasonality on the concentration of

Field findings about milk ethanol stability: a first report of interrelationship between α‐lactalbumin and lactose

“…Previous studies have indicated that the correlation between milk ethanol stability and milk protein fractions could be mainly influenced by -casein and -lactoglobulin, which are related to micellar stability. 5,13 By contrast, Botaro et al 32 were unable to find any influence of -lactoglobulin on the ethanol stability of milk. Thus the consensus view is that milk ethanol stability is a phenomenon with many variables, going well beyond micellar clotting and just one dominant role: calcium ion activity.…”

Genetic Variants and Allele Frequencies of Kappa Casein in Egyptian Cattle and Buffalo Using PCR-RFLP

“…On the other hand, Allmere et al (1998) and Oner and Elmaci (2006) reported the presence of 'A' and 'B' alleles for K-Ca, with highest frequency 'B' allele in Holstein breed. Cows with 'AB' and 'BB' genotypes showed significant higher milk proteins and fat content when compared with that of 'AA' genotype (Botaro et al, 2009) suggested that selection of cows with 'AA' genotype for meat production is preferred.…”

Seasonal variation, method of determination of bovine milk stability, and its relation with physical, chemical, and sanitary characteristics of raw milk

“…Other milk characteristics were not consistently related to stability. Some studies have reported significant effects on stability related to the casein composition , while other have not reported significant effects (Marques et al, 2011;Botaro et al, 2007Botaro et al, , 2009. Somatic cell count (SCC) has been controversially related to low stability, as some studies reported a relation between high SCC and low stability (Oliveira et al, 2011;, while others have shown no relation (Kolling, 2012).…”