Short communication: Metritis affects milk production and cull rate of Holstein multiparous and primiparous dairy cows differently.

Metritis, a common transition disease in dairy cows, reduces milk production during the duration of the disease. To our knowledge, no work has investigated the short-term effects of metritis on feed intake and the long-term consequences on milk yield and risk of culling. The objectives were to determine the effect of metritis on 305-d lactation curves, dry matter intake (DMI), reproduction, and the probability of being culled. Identifying differences in response to metritis between primiparous and multiparous cows was of interest. Milk records were collected twice daily from Holstein cows diagnosed with puerperal metritis (11 primiparous and 16 multiparous) or classified as healthy (14 primiparous and 43 multiparous) during the first 3 wk after calving. Metritic cows were treated at the discretion of the herd veterinarian. Lactation curves of healthy and metritic cows were compared using a mixed model with a Wilmink function. Differences in DMI, days open, and the number of services per conception were assessed using mixed models. The probabilities that cows with and without metritis were not bred, were bred but never confirmed pregnant, or were culled were compared using Fisher's exact tests. Primiparous and multiparous animals were assessed separately. Multiparous cows with metritis produced less milk (35.1±1.5 vs. 39.2±1.0 kg/d), ate less during the 3 wk after calving (12.2±1.2 vs.14.0±0.8 kg/d), and were more likely to be culled (50.0%) than healthy cows (20.9%). The decision to cull was likely influenced by the lower milk yield in early lactation as a result of metritis; the decision to cull was made early, as 7 of the 8 culled metritic cows were not bred. No differences were found in any measurement between primiparous cows with and without metritis. These results indicate that metritis in early lactation has long-term effects on multiparous cows but not primiparous cows.