Pregnancy loss attributable to mastitis in primiparous Holstein cows

a matched case-control study

Abstract

Several observational studies have produced different levels of strength of evidence indicating that mastitis can be a predisposing factor for pregnancy loss (PL) in dairy cows. In some of those studies, clinical mastitis before or after AI, subclinical mastitis before AI, and clinical mastitis during early lactation in combination with low BCS increased the risk of subsequent PL. Some studies, however, failed to identify a relationship between PL and clinical or subclinical mastitis after AI in dairy cows. To our knowledge, no studies have simultaneously examined the relationships between PL and exposures to clinical, subclinical, or clinical and subclinical mastitis during different exposure periods (for instance, before breeding and during gestation) in dairy cows. The objective of the study reported here was to examine the association between PL and previous exposure to clinical or subclinical mastitis before breeding or during gestation in primiparous Holstein cows.