A nutritional risk factor for early metritis in dairy farms in France

Abstract

A survey was conducted in dairy herds in France (79 herds were surveyed during 2–4 years in six regions). Two groups of herd-years (free of brucellosis) were constructed according to their early metritis cumulative incidence (EMEI) in order to detect nutritional risk factors for the disease. The first group included the 10% of herd-years with the highest EMEI (EME + group; n=24); the second group (EME − group) included the 24 herd-years with the lowest EMEI and with the same number of herd-years for each region and each annual period. Herd-years with both high EMEI and low EMEI/retained placenta incidence ratios were removed from the study in order to rule out herds in which EME was mainly connected with retained placenta. The herd data concerned EMEI and four other clinical disease incidences, Q-fever serology, herd size, breed, housing system, use of a calving pen, milk yield and composition, calving number, season of calving, duration of the dry period, number of feeding days for 14 major feedstuffs given to cows during the dry period and the presence in the diet of vitamins A, D and E. Data were analysed using barycentric analysis (a form of discriminant analysis) to find the variables discriminating EME − and EME + herd-years. EME + herd-years were characterised by longer durations of feeding dry cows with urea and by more winter calvings. These two variables explained 26.9% of the total variation in the barycentric analysis. None of the remaining 26 variables explained more than 10% of the variation. Dietary urea feeding might involve environmental changes in the uterus with subsequent easier bacterial growth and lowered local immune defence. Winter calvings might be associated with poor hygienic conditions which would favour uterine infections in the early postpartum period.