[Nutritional factors and mammary inflammatory infection in the dairy cow. Ecopathological approach during the peripartum period].

The relationships between nutrition and udder inflammation/infection were studied in the dairy cow using an ecopathological approach. The study ('enquête écopathologique Bretagne') was performed over 4 yr in French herds with high-lactating cows. A long distribution time of Italian ryegrass silage and a low quantity of dietary cereal-based concentrates in the first 2 months of lactation was linked with low milk leukocyte counts, probably due to a high dietary energetic level or to a polyunsaturated fatty acid imbalance and a subsequent decrease in the synthesis of leukotriene LTB4. In the late gestation period, a long distribution time of fresh English rye-grass, which induced high uraemia and a larger distribution of vitamins A, D and E, was related to lower frequencies of major pathogens in the milk.