The objectives of this study were to assess the efficacy of
antibiotic treatment for preventing postpartum
uterine disease among cows at high risk of
uterine disease, and to assess the efficacy of
PGF(2α) for treating cytological
endometritis (CYTO) and purulent
vaginal discharge (PVD). A total of 2,178 Holstein cows in 6 herds were enrolled in a randomized clinical trial. Within 24h after parturition, cows were classified at being at high risk of
uterine disease (HRUD; n=1,017) if they had twins,
dystocia, or
retained placenta. All remaining cows were classified as being at low risk of
uterine disease (LRUD; n=1,161). Cows in the HRUD group were randomly allocated in a factorial design to receive
ceftiofur crystalline free
acid (CCFA) at 24h after parturition or be untreated, and to receive
dinoprost (
PGF(2α)) at 35 and 49 (±3) days in milk (DIM) or to be untreated. Cows in LRUD were randomly allocated to receive
PGF(2α) at 35 and 49 (±3) DIM or to be untreated. Serum
progesterone was measured at 21, 35, 49, and 63 (±3) DIM. Cows were examined at 35 (±3; exam 1) and 56 (±3; exam 2) DIM for CYTO (by cytobrush device; ≥6% polymorphonuclear cells in endometrial cytology) and for PVD (by Metricheck device; mucopurulent or purulent
vaginal discharge). Statistical analyses were performed using multivariable logistic regression models accounting for herd clustering. Treatment with CCFA in HRUD cows was not associated with the probability of metritis overall, but interactions occurred such that CCFA decreased the incidence of metritis among HRUD cows that did not have
retained placenta and among cows of parity ≥2. Treatment with CCFA in HRUD cows decreased the probability of PVD at exam 1. Treatment with
PGF(2α) did not affect the probability of cure of CYTO or PVD irrespective of
progesterone concentration at the time of treatment. Among cows affected by CYTO or PVD at exam 1, 66 and 63%, respectively, had spontaneously cured at exam 2. Cows persistently affected at exam 2 had an increased time to pregnancy and were more likely to have both CYTO and PVD at exam 1. Administration of
PGF(2α) at both 5 and 7 wk postpartum did not mitigate the effects of CYTO or PVD on reproductive performance. Clinical approaches to treatment of chronic postpartum
reproductive tract infection and
inflammation should be reassessed.