Spontaneous Lipolysis in Milk Throughout the Stages of Lactation of Individual Cows

Summary The milk from each of four cows maintained under controlled conditions was checked for spontaneous lipolysis four times a week during a complete lactation by the silica gel method. The average acid degree values (ADVs) were: Cow 1—0.57, Cows 2—0.75, Cows 3—1.25, and Cow 4—1.28. The ADVs increased as lactation progressed with Cows 2, 3, and 4. Samples that were rancid organoleptically were produced only by Cows 3 and 4. Most of these samples were taken during the last month of lactation. There was considerable week-to-week and cow-to-cow variation. The average p.m. ADVs of Cows 2 and 3 were significantly higher than the average a.m. ADVs.