139
Rare Genetic Variants and the Regulation of Bovine Milk Composition
Bulking of milk by farm, tanker and factory silo will produce an average milk composition for a collection district. Thus the process of milk collection conceals the extent of natural variation in milk component concentrations between individual cows. Variation in milk composition between individuals is mostly genetically determined and hence can be harnessed through specific selection and breeding strategies.
This brief review gives examples of novel and some rare genetic variants that exist at low frequency in genes relatively well known in terms of their role in milk composition. Such variants have been identified by high-throughput phenotypic analysis of milk and sequencing of the target genes from cattle presenting extreme phenotypes.
Identification of naturally-occurring genetic variations to develop lines of animals with more extreme milk composition phenotypes is relatively straightforward. Industry development of such variants in cattle populations presents several commercial challenges.
Keywords:
Dairy cattle
Milk composition
Genetics
