Reproduction Abstracts

Dairy cow fertility has declined over the past 50 years coinciding with increased milk production. Uterine health is an important factor with endometritis prevalent in high-yielding dairy cows. This study assessed the association between uterine disease on reproductive performance in 78 commercial UK dairy herds. Data from 59 118 lactations (n=29 157 cows) was collected from 2000to 2009 and included presence of uterine disease, calving date, and insemination information. Linear mixed model analyses were performed to determine the association between cows experiencing uterine disease their conception rate, days to first insemination (DFS), calving to conception interval (CCI) and calving interval (CI). The proportion of animals culled was compared using χ²-test. The mean incidence of endometritis was 12% per lactation. The DFS, CCI and CI were extended by 7 (P<0.05), 20 days (P<0.001) and 26 days (P<0.001), respectively in cows, which had experienced uterine disease in that lactation. The extension in the CCI was, in part, explained by a lower first service conception rate (P< 0.0001) in cows that had post-partum uterine disease (24.3%) compared to controls (38.0%). Furthermore, there was an increase of 0.8 services per conception (P<0.001). The culling rate in cows that experienced uterine disease was greater (24.9%; P<0.001), compared with the control group (21.2%). This study has quantified the negative associations between cows experiencing uterine disease and subsequent reproductive performance in UK commercial dairy herds, with the biggest relationship appearing to occur on the ability of cows to re-conceive.