BIOLOGICAL PREDICTORS FOR EARLY CLINICAL MASTITIS OCCURRENCE IN HOLSTEIN COWS UNDER FIELD CONDITIONS IN FRANCE

Individual risk factors for clinical mastitis within the first month o f lactation (early clinical mastitis, ECM) were analyzed in 695 Holste in multiparous cows (561 ECM- and 134 ECM+) which were clinical mastit is-free during the previous lactation. They belonged to 44 herds from the French Brittany region and were surveyed for 4 years. Individual b iological parameter levels during the last 2 months of gestation, prod uction of the preceding lactation and calving conditions and health we re the available explanatory variables. The construction and explanati on model used multiple logistic regression run with herd as a fixed ef fect. High precalving plasma ceruloplasmin oxidase (p < 0.01) and low glutamate dehydrogenase (p < 0.05) activities, high 305-day previous-l actation milk yield (p < 0.001) and milk protein content at the last m ilk-test day before drying-off(p < 0.01) were the significant risk fac tors for ECM occurrence. Intensive production and unsatisfactory dieta ry conditions (energy and antioxidants) would increase ECM risk in the dairy cow. Further studies should be conducted to determine if metabo lic and/or genetic factors could explain the relationship between ceru loplasmin and subsequent ECM occurrence. (C) 1998 Published by Elsevie r Science B.V.