Milk lipolysis is defined as the hydrolysis of triglycerides, the major component of milk fat. Short-chain fatty acids consequently released in milk are responsible for rancid flavor, unacceptable for consumers, in milk and dairy products. In addition, the presence of partial glycerides impairs milk functional properties such as foaming and creaming abilities. Milk lipolysis, routinely measured by accredited inter-professional dairy laboratories therefore represents an important criterion to assess the quality of milk. High lipolysis indexes in milk lead to appreciable loss of market access for dairy farms. Milk spontaneous lipolysis is a complex interplay between farming practices, animal physiology and animal genetics. In addition, milk induced lipolysis may occur during milking or dairy products manufacturing as results of thermal and/or mechanical shocks during milking and cooling. Lipolysis can thus occur throughout the "milk way", from "udder to cheese". The LIPOMEC employs a multi-actor approach to meet a threefold objective: ? To study the lipolytic system constituted by the lipase, its substrate (the milk fat globule) and a balance of activating or inhibiting cofactors in the three dairy species through the characterization of lipase regulatory networks in milk and/or mammary epithelial cells; ? To establish breeding and feeding strategies those ensure optimal and stable milk quality all year round; ? To develop tools and techniques to monitor and reduce lipolysis all along the "milk way". Our approach is definitely integrative, including animal science, milk biochemistry, milk biophysics, proteomics, lipidomics, genetics, transcriptomics, cell biology techniques, data modeling, and statistics. Interactions between genetics, physiology, farming practices and technological factors related to the milking process will be considered. LIPOMEC is the first large-scale integrative project to study the lipolytic system in the milk and mammary gland from ruminant species.