The lipidic diet of the cow and its impact on the production, composition and technological properties of milk

The addition of commercial fat supplements to dairy rations is common practice. The high caloric value of these ingredients supports the high requirements of early lactation cows. The fatty acid (FA) profile of commercial fat supplements has a significant impact on the content and composition of milk fat. In Quebec and Canada, producers are increasingly using saturated fat supplements to produce milk that is fatter and therefore more in line with market needs. Because of the efficiency of transferring palmitic acid (16:0) from the ration to the milk, supplements enriched with this GA are becoming more and more popular among producers. Previous studies have shown that the addition of saturated fat to the ration decreases the casein:total protein ratio, and therefore cheese yield. Also, the fat profile of the milk is a key determinant of yields in butter production. However, very few studies have compared the different saturated fat supplements currently used in cow diets with respect to their effects on the technological properties of milk and its suitability for processing, whether for cheese or butter production.

The general objective of the proposed research program is to identify nutritional and management strategies aimed at producing milk of ideal composition for the processing market and, ultimately, to identify adjustments in processing conditions that are most likely to improve yields based on the fine composition of the milk. We therefore propose to conduct a first animal phase where four (4) rations (with or without saturated fatty acids and high or low protein degradability) will be served to the animals, with the aim of determining the impact of saturated fatty acid supplements on milk production and composition, its GA and protein profile, as well as its technological properties, and to verify if these impacts can be modulated by the other ingredients of the ration. A second animal phase will be carried out where rations with or without saturated fats will be combined with different milking regimes (2x vs 3x/day). This second experiment will allow us to verify if the potential effects of lipid supplements on the technological properties of milk are influenced by milking frequency. A technico-economic analysis will allow us to evaluate the impacts of the different nutritional strategies on the sustainability of our dairy production and processing enterprises.