Influence of seroreactivity to leptospira and reproductive failures in recipient mares of equine embryo transfer programmes.

This research article investigates the impact of Leptospira seroreactivity on reproductive failures in horses involved in embryo transfer programmes, concluding a significant correlation between Leptospira infection and increased rates of embryonic death, abortion, and perinatal death.

Study Aim and Approach

• The primary aim of the study was to establish a link between seroreactivity to the bacteria Leptospira and the reproductive efficiency of recipient mares in embryo transfer (ET) programmes.
• Leptospira is a genus of bacteria that can cause a variety of medical conditions in animals. In horses, it has been associated with various reproductive complications, including early embryonic death, abortion, and perinatal death.
• To determine the effect of Leptospira infection, the researchers conducted a serosurvey from August 2007 to March 2009 in five herds from Rio de Janeiro, Brazil. These herds have been noted for high rates of reproductive failure.

Results and Findings

• A total of 338 recipient mares were tested using a microscopic agglutination test to determine the presence of Leptospira antibodies. Their findings revealed that 66.9% of the mares tested were seroreactive, suggesting that they had been infected with Leptospira at some point.
• The most prevalent serovars, or distinct variations within a species of bacteria, identified in the study were Bratislava and Copenhageni.
• The study found a strong statistical association between seroreactivity to Leptospira and reproductive failure (p < 0.001). Data suggests that a seroreactive mare is 1.8 times more likely to experience reproductive failure than a seronegative mare.
• The study also established a significant correlation between Leptospira seroreactivity and specific types of reproductive failures: early embryonic death (p < 0.0001; RR 8.4), abortions (p < 0.0001; RR 3.5), and perinatal death (p < 0.05; RR 7.3).

Study Conclusion

• Based on the study’s findings, the researchers concluded that seroreactivity to Leptospira bacteria is linked to reproductive failure at all pregnancy stages in recipient mares.
• Such infection can significantly hinder the success of equine ET programmes, making it a crucial factor to screen for and manage in equine breeding practices.