Eligibility Criteria

In the published protocol, we planned to include studies where the post-calving IMI status was determined within 14 days in milk (DIM), to ensure that the new IMI or elimination most likely occurred during the dry period (vs. in the early lactation). However, in some articles, cows were sampled twice after calving (for instance, 3–4 DIM and 5–18 DIM), and a parallel interpretation of the two milk samples was used to define IMI status. Hence, some studies relied on testing within an interval that extended slightly beyond 14 DIM but was mostly within 0–14 DIM. We decided to retain these studies (5, 6, 15). In the published protocol, we indicated CM incidence during the first 0–4 months after calving as a studied outcome. More precisely, we did use the CM data from studies with a shorter follow-up period and otherwise extracted the data up to a maximum of 4 months in milk.