Vulvovaginal laceration as a risk factor for uterine disease in postpartum dairy cows.

The main objective was to evaluate the association between vulvovaginal laceration and uterine diseases in dairy cows. The secondary objectives were to evaluate the association between vulvovaginal laceration and cyclicity, and reproductive performance. The vulvovaginal region of 660 Holstein cows from a 5,000 lactating-cows herd was inspected at 4d in milk (DIM) for the presence of lacerations, and scored (VLS) as follows: 0=no laceration; 1=laceration <2cm at the dorsal commissure of the vulva or lateral walls of the vulva/vagina; 2=laceration ≥2cm at the dorsal commissure of the vulva or at the lateral walls of the vulva/vagina, or both. Vaginal discharge was scored at 4, 6, and 8 DIM for diagnosis of metritis, and then at 32 DIM for diagnosis of purulent vaginal discharge (PVD). Data were analyzed using LOGISTIC and PHREG procedures of SAS. Cows with VLS 2 had greater incidence of metritis than cows with VLS 0 (69.1 vs. 42.4%), and cows with VLS 1 tended to have greater incidence of metritis than cows with VLS 0 (52.0 vs. 42.4%). Cows with VLS 2 had greater incidence of PVD than cows with VLS 0 (56.5 vs. 43.1%). A lower proportion of cows with VLS 2 than VLS 0 were cyclic by 64 DIM (70.0 vs. 86.8%). A lower proportion of cows with VLS 2 than VLS 0 were pregnant at 60 d after first AI (28.7 vs. 33.6%). Proportion of pregnant cows at 60d after AI tended to be lower for VLS 1 than VLS 0 (28.4 vs. 33.6%). Hazard of pregnancy by 300 DIM was not affected by VLS. Hazard of pregnancy was decreased for cows with metritis, PVD, and anovular cows. In summary, vulvovaginal laceration was associated with uterine disease and cyclicity, which were negatively associated with reproductive performance. Vulvovaginal laceration was recognized as a risk factor for postpartum uterine disease.