Effects of endometritis on reproductive performance of zero-grazed dairy cows on smallholder farms in Rwanda.

Endometritis is a prevalent post-partum uterine infection in dairy cows resulting in suboptimal reproductive performance. The hypothesis was that endometritis status is associated with suboptimal reproductive performance of postpartum dairy cows managed under zero-grazing feeding practice on smallholder farms. In this study, there was evaluation of effects of endometritis diagnosed at 38.5 ± 14.7 days postpartum (dpp) on subsequent reproductive performance. Reproductive performance of 436 cows from 345 farms was recorded for 210 dpp. Values for reproductive performance indicators were less (P < 0.05) in cows determined to be positive compared to negative for endometritis. Cows that tested positive, as compared to negative, for endometritis had longer periods after parturition until initiation of oestrous cycles (median, interquartile range; 85.0, 57.5-127.0 and 62.6, 49.0-90.0 days, respectively), longer durations before being detected pregnant (95.5, 61.8-145.5 and 63.0, 50.0-83.0 days, respectively), lesser pregnancy rates as a result of the first breeding postpartum (16.5% and 32.7%, respectively), more natural-mating or artificial inseminations per pregnancy (1.3 ± 0.1 and 1.1 ± 0.0, respectively) and more occurrences of anoestrus postpartum (48.4% and 11.7%, respectively). These results provide evidence of a strong association between endometritis and suboptimal fertility performance in zero-grazed cows on smallholder farms in Rwanda. Considering there were 70.2% of cows in the present study were diagnosed with endometritis, this is indicative of a widespread herd health issue, warranting that field veterinary practitioners prioritise endometritis in their herd health service delivery to smallholder dairy farmers for effective disease management and herd sustainability.