Optimalait: Management of Genetic and Feed Resources to Control Milk Fatty Acid Composition

The Optimalait project collected data from 1,500 commercial farms in 2009–2010, phenotyping the milk fatty acid profile of 190,000 dairy cows, goats, and sheep using mid-infrared spectrometry and genotyping 12,000 individuals with pangenomic SNP chips. It demonstrated that feeding strategies are the most effective lever for modifying milk fatty acid composition, while lactation stage, season, and age at first parturition also significantly influence fatty acid profiles. Genetic parameters for fatty acids showed moderate heritability and consistent genetic variation across species and breeds. Numerous QTL were mapped, many colocalizing across traits and breeds, revealing potential for enhanced dairy management and genomic selection tools.