Amino Acid Composition and Biological Value of Proteins in Milk of White-and-Black Cows and their Respective Crosses with Montbeliarde

Abstract

The relevance of the survey is to explore the selection approaches to increasing the mass fraction of protein and its biological value in the milk produced by Black-and-White cows. The objective of the survey is to study the amino-acid composition and the biological value of protein in the milk produced by Black-and-White cows and their respective crosses with Montbeliarde in order to identify the prospects for this breed in the Black-and-White commercial herds. It was ascertained that the mass fraction of protein in milk of the half-blood crosses (1/2 MB × 1/2 BW) made up 3.50%, which was 0.26% higher than that in their Black-and-White peers. Despite full ranges and almost equal proportions of essential amino acids in the milk protein of crossbred and purebred cows, comprising 48.0% each, the crosses tended to have significantly higher contents of both the essential amino acids—isoleucine, lysine, tyrosine, and threonine—except an inferior concentration of tryptophan and the nonessential amino acids: alanine, arginine, and aspartic acid + asparagine. The results provide a profound basis for the evidence to recommend the use of Montbeliarde cows in the Black-and-White commercial herds in order to increase the mass fraction of milk protein and to improve its amino acid composition.