The genetic polymorphism and content ofβ-lactoglobulin in milk of yak, cattle-yak and dairy cattle

Genetic variants of β-lactoglobulin(β-LG) are investigated in yak, half-lactating yak, cattle-yak and Chinese-Holstein by PAGE. The dominant genotypes of β-LG are BE in yak and half-lactating yak, however, no A genotype. The dominant genotypes of β-LG are BE in cattle-yak, AB in Chinese-Holstein. Meanwhile, genotype of β-LG with three bands of AA, BB and AB are observed in Chinese-Holstein, but there is no E genotype. The content of β-LG in milk is determined by ELASA. There are some differences between total content and genotypes in yak, cattle-yak, half-lactating yak and Chinese-Holstein. We also can see the different expression of genotypes.