β-Lactoglobulin variation in milk from individual cows

Abstract

Summary: The β-lactoglobulin types of 812 individual cows of various breeds were determined by paper and polyacrylamide gel electrophoresis. The results support the hypothesis that β-lactoglobulins A and B are controlled genetically by codominant autosomal alleles (Lg^Aand Lg^B).Milks from 5 heterozygous cows (Lg^A/Lg^B) were examined by free electrophoresis and column chromatography to estimate the relative quantities of β-A and β-B produced by these animals. The results indicate that β-A and β-B are produced in approximately equal amounts, with β-A being slightly in excess of β-B.Lacteal secretions were obtained from 2 castrated males and typed for β-lactoglobulin by means of paper electrophoresis. These animals were found to produce β-lactoglobulins (B and AB) consistent with their expected genotypes as deduced from pedigree analysis.