163 EFFECT OF PUERPERAL METRITIS ON REPRODUCTIVE AND PRODUCTIVE PERFORMANCE IN DAIRY COWS IN ARGENTINA

The objectives of this study were to evaluate the reproductive and productive performance of dairy cows with and without puerperal metritis and to evaluate the effectiveness of using a long-acting antibiotic (200 mg mL–1 ceftiofur, Excede, Pfizer Animal Health, New York, NY, USA). Dairy cows in one dairy farm calving from July 2009 to January 2010 were examined between 3 and 14 days postpartum and classified based on vaginal discharge into 3 groups: cows with normal discharge (control); cows with purulent or red-brown vaginal discharge without foul smell, and cows with purulent or red-brown vaginal discharge with foul smell (Sheldon et al. 2006 Theriogenology 65, 1516–1530). Cows in the first 2 groups were not treated, whereas those in the third group were randomly allocated to receive 1 mL/30 kg of body weight of Excede subcutaneously behind the ear or remain untreated. From the 640 cows examined, 372 (58.2%) had normal discharge, 86 (13.4%) had a discharge without foul smell and 182 (28.4%) had a discharge with foul smell. Kaplan-Meier survival curves were obtained to compare pregnancy rates across days postpartum, and differences between curves were tested with the log rank statistic. Proportional hazards regression with PROC PHREG Cox of SAS were done to estimate the risk of pregnancy in terms of treatment, parity (first parity or ≥2 parities), type of delivery (normal or assisted), and milk production. Finally, lactation curves were modeled using SAS PROC NLMIXED to estimate the cumulative milk production at 305 days. Survival curves differed between cows in the control group and those with foul-smell discharge that were not treated (P < 0.01) and between untreated versus treated cows (P < 0.01) in the latter group. Survival curves of cows with discharge but without foul smell were intermediate and did not differ from those in the control group (P = 0.2) and those with foul smell discharge and treated (P = 0.1), but tended to be different from those with foul smell discharge and not treated (P = 0.056). The postpartum interval to achieve a 25% pregnancy rate was 72 days for cows in the control group, 73 days for cows with foul smell and treated, 83 days for cows with discharge without foul smell, and 95 days for those with foul smell and not treated. The chance of pregnancy in cows in the control group was 1.98 times higher (95% CI = 1.33, 3.08) and in cows with foul smell and treated was 2.16 times higher (95% CI = 1.37, 3.50) than those with foul smell and not treated. Finally, the chance of pregnancy in cows with discharge but without a foul smell tended to be higher (P = 0.08) than those with foul smell that were not treated, but did not differ with the other 2 groups. Parity, type of delivery, and production level did not affect pregnancy rates. Cumulative 305-day milk production was higher (P < 0.01) in control cows than those with vaginal discharge, regardless of smell and regardless of treatment. It is concluded that puerperal metritis affects the reproductive and productive performance of dairy cows, and the treatment with Excede was effective in reducing the adverse effects on reproductive performance.