Effect of intrauterine treatment with cephapirin on the reproductive performance of seasonally calving dairy cows at risk of endometritis following periparturient disease

Objective To determine the effect of intrauterine cephapirin (0.5 g) treatment on the reproductive performance of cows diagnosed as at risk of developing endometritis. Methods Cows (n = 1325) from 17 seasonal calving dairy herds were enrolled if they had been calved for more than 6 days and had a condition that placed them at risk of endometritis. Half were treated with intrauterine cephapirin at an examination performed 28-37 days prior to mating start date (MSD). Cows were scored for body condition, their vaginal discharge was scored using vaginoscopy (VV), and the uterus and ovaries were assessed by rectal palpation. Results Overall, there was no significant treatment effect on reproductive performance. In 945 modified at risk (MAR) cows the effect of treatment varied with the calving to treatment interval (CTI) and VV status. For the subset of 229 MAR cows with CTI <= 28 days, treatment improved the proportions of first-service conception (OR 3.1; P < 0.01) and 6-week in-calf (OR 2.1; P < 0.05), and reduced the mean MSD to conception interval by 20 days (P < 0.05). The difference was greater in cows with a positive VV score (1-3). Treated VV-negative cows with CTI > 48 days had a reduced proportion of cows in-calf by 6 weeks (OR 0.58; P = 0.056) compared with untreated cows. Conclusion Intrauterine cephapirin infusion of MAR cows improved reproductive performance, depending on CTI. The greater treatment effect in VV-positive cows suggests that VV scoring is a useful tool for the diagnosis of endometritis.