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 of lactation (early clinical mastitis, ECM) were analyzed in 695 Holstein multiparous cows (561 ECM- and 134 ECM+) which were clinical mastitis-free during the previous lactation. They belonged to 44 herds from the French Brittany region and were surveyed for 4 years. Individual biological parameter levels during the last 2 months of gestation, production of the preceding lactation and calving conditions and health were the available explanatory variables. The construction and explanation model used multiple logistic regression run with herd as a fixed effect. High precalving plasma ceruloplasmin oxidase (p < 0.01) and low glutamate dehydrogenase (p < 0.05) activities, high 305-day previous-lactation milk yield (p < 0.001) and milk protein content at the last milk-test day before drying-off(p < 0.01) were the significant risk factors for ECM occurrence. Intensive production and unsatisfactory dietary conditions (energy and antioxidants) would increase ECM risk in the dairy cow. Further studies should be conducted to determine if metabolic and/or genetic factors could explain the relationship between ceruloplasmin and subsequent ECM occurrence. (C) 1998 Published by Elsevier Science B.V.