Milk fat content (MFC)

Milk fat content refers to the concentration of lipids, predominantly triacylglycerols (approximately 98%), secreted in mammalian milk during lactation [2, 14]. It is not a single molecular target but a complex phenotypic trait regulated by a coordinated network of enzymes such as Diacylglycerol O-acyltransferase 1 (DGAT1), Fatty Acid Synthase (FASN), and Stearoyl-CoA Desaturase (SCD), as well as hormonal signaling through the JAK2/STAT5 pathway [3, 6, 7]. In the agricultural sector, milk fat content is a primary target for genetic selection and nutritional management to optimize the energy density and manufacturing properties of dairy products [13]. In human health, the consumption of milk with varying fat content is a significant dietary factor linked to metabolic outcomes, cardiovascular health, and the delivery of bioactive lipids like conjugated linoleic acid (CLA) [9, 11]. Interventions such as the administration of specific CLA isomers or bovine somatotropin (bST) can significantly modulate milk fat synthesis by altering the expression of lipogenic genes or shifting nutrient partitioning in mammary epithelial cells [12, 14].

Other names

Milk fat percentageMilk lipid concentrationMilk fat yieldMilk fat proportion

Modulation of milk fat content is achieved through the inhibition of lipogenic gene expression (e.g., trans-10, cis-12 CLA downregulating FASN and SCD via SREBP1 suppression), hormonal stimulation of mammary metabolic activity (e.g., somatotropin increasing nutrient uptake), or the alteration of rumen microbial fermentation to change the availability of fatty acid precursors (e.g., monensin increasing propionate production).