Randomized clinical trial of intrauterine cephapirin infusion in dairy cows for the treatment of purulent vaginal discharge and cytological endometritis

The objectives of this study were to quantify the effect of an intrauterine infusion of cephapirin on reproductive performance at first service of postpartum dairy cows affected by purulent vaginal discharge (PVD) and cytological endometritis (ENDO) using different diagnostic strategies, and to determine if the presence of prolonged anovulation would influence the magnitude of treatment benefit. In total, 2,259 Holstein cows in 28 herds were enrolled in a randomized clinical trial. At 35 (±7) days in milk (DIM), cows were diagnosed with PVD using the Metricheck device (Simcro, Hamilton, New Zealand), with cytological endometritis using endometrial cytology (ENDO-CYTO), and with cytological endometritis using leukocyte esterase (ENDO-LE). Regardless of reproductive tract disease status, cows were randomly assigned to receive an intrauterine cephapirin infusion or to not be treated. Serum progesterone was measured at 35 and 49 (±7) DIM (14 d apart); cows were considered to have prolonged anovulation if progesterone was <1 ng/mL at both times. Reproductive events of cows were collected until 200 DIM. Statistical analyses were conducted using multivariable mixed logistic regression models. Intrauterine cephapirin treatment was associated with an increased first-service pregnancy risk in cows diagnosed with PVD (no treatment: 15.4%; treatment: 31.4%), ENDO-CYTO (no treatment: 16.2%, treatment: 24.4%), and ENDO-LE (no treatment: 15.8%; treatment: 25.1%), but not in cows unaffected by any form of reproductive tract disease (no treatment: 34.8%; treatment: 32.6%). Cephapirin treatment was also associated with an increased first-service reproductive performance in cows affected simultaneously by both PVD and ENDO-CYTO (no treatment: 8.7%; treatment: 23.4%). The effect of cephapirin treatment in anovular cows (no treatment: 21.0%; treatment: 26.4%) was numerically lower than in cyclic cows (no treatment: 22.7%; treatment: 34.1%). Overall, an intrauterine infusion of cephapirin improved first-service pregnancy risk in cows with postpartum reproductive tract disease and this effect was influenced by postpartum anovulation status.