Understanding the Regulation of Milk Fat Synthesis and Its Potential Application in Herd Management

摘要

There is growing interest in nutrition strategies focused on increasing the yield of milk components. The yields of milk fat and protein are the major contributors to the price that producers receive for milk. In an economic analysis assessing the value of milk components, a 5% increase in fat yield, protein yield, and milk yield increased net farm income by 13%, 15%, and 2%, respectively (St-Pierre, 2017). This reinforces the importance of focusing on increasing the yield of milk components and notmilk yield per se to maximize milk price and income. Synthesis of milk fat in the mammary gland is a highly-coordinated process involving de novo synthesis of fatty acids (FA) and incorporation of preformed FA. Importantly, several factors can influencemilk fat synthesis, including genetics (breed and selection), stage of lactation, parity, mastitis, dietary forage and grain levels, diet fermentability, dietary FA level and profile, and seasonal and regional effects. Furthermore, the potential utilization of milk FA as a management tool has recently received attention. We will briefly review the biological processes for milk fat synthesis, the interrelationship between different FA in the regulation of milk fat synthesis, and the potential for nutrition and management decisions based on milk FA analysis.