Le point sur la lipolyse du lait de vache : facteurs de variation et mécanismes biochimiques

Lipolysis is an enzymatic reaction, which leads to off-flavor in milk and impairs technological properties of milk. In some regions of France, lipolysis is one of the milk payment criteria. Cow susceptibility to lipolysis affects tank lipolysis variations. “Non-susceptible” cows’ present low and stable lipolysis rates during their life although “susceptible” cows present fluctuating lipolysis rates, varying with husbandry factors, milking systems and milk storage. According to the type of farming system, lipolysis can be reduced by selecting “non-susceptible“cows, by drying off“susceptible” cows from 6 months of gestation, and by reducing milking frequency to 2 milkings per day. The balance of rations (energy, proteins, lipid supplements) must be considered, especially in early lactation for high merit multiparous cows. Pasture is associated with low lipolysis rates. Careful maintenance of milking systems is important to reduce dysfunctions and their impacts on lipolysis. Lipolysis is on average higher for milking robots than for conventional milking equipment; however, continuous improvements are being made in the field. The biochemical mechanisms of lipolysis are still being studied.