Effects of milk protein polymorphism and composition, casein micelle size and salt distribution on the milk coagulation properties in Norwegian Red cattle

Effects of milk protein polymorphism and composition, casein micelle size and salts distribution on the coagulation properties of milk from 99 Norwegian Red cattle (NRF) were studied. Genetic variants of alpha(S1)-casein (CN), beta-CN, kappa-CN and beta-lactoglobulin (LG) affected rennet coagulation properties of milk. Significant effects of kappa-CN and the composite genotype as alpha(S1)-kappa-CN were observed on acid coagulation properties. Relative concentrations of milk proteins were significantly affected by individual casein genotypes and the composite genotype of asi-13-K-CN while, the relative concentration of beta-LG was only affected by beta-LG genotypes. The salts distribution in milk and the concentration of milk proteins affected both rennet and acid coagulation properties. Milk protein genotypes associated with better rennet coagulation, impaired the acid coagulation properties. However, alpha(S1)-beta-kappa-CN BB-A(1)A(2)-BE and BB-A(2)A(2)-BB were associated with poor rennet and acid coagulation properties. Breeding programs should focus on decreasing these genotypes in NRF cattle. (C) 2016 Elsevier Ltd. All rights reserved.