Milk Fat Depression:

Diet-induced milk fat depression (MFD) causes milk fat yields to drop without lowering milk volume or protein percent. All cows are likely to experience a degree of MFD. High-producing cows are the most severely impacted.

With milk fat depression, the fat percentage can fall dramatically, reducing income from milk fat by 25%. Dietary and environmental factors such as rations high in unsaturated fats and starch increase the risk of the formation of the compounds that inhibit milk fat synthesis.