We investigated variants of the six major milk proteins in 3,824 cattle representing 113 breeds with wide geographical distribution using whole genome sequencing data.
To date, 63 variants of six major bovine milk proteins (aS1-CN, ß-CN, aS2-CN, ?-CN, a-LA, and ß-LG) have been described. These variants are caused by changes in the amino acid sequence of the mature protein, primarily resulting from missense variations in the exons of genes or splice sites. Several of these variants are known to be associated with milk production traits, cheese-processing properties, and the nutritional value of milk. In the past, milk protein variants have been identified in a limited number of breeds, especially in dairy cattle. The objective of this study was to investigate variation in milk proteins in a large number of cattle breeds based on whole genome sequencing data.