Experimental models of endotoxaemia related to abortion in the mare.

The study investigates the impact of administering Salmonella typhimurium endotoxin to mares via different methods to understand the effects of endotoxaemia, a condition related to abortion. The findings show that horses are significantly sensitive to endotoxins, and a brief exposure can lead to clinical symptoms and reproductive issues.

Research Methods

• The researchers ran trials of Salmonella typhimurium endotoxin administration via three different routes; these included a single high dose, repeated doses, and a continuous low-dose infusion. Each method was evaluated for its effects on prostaglandin F2 alpha release (a hormone that regulates inflammation), leukocyte count (white blood cells crucial for immunity), and overall clinical response.

Key Findings

• All three methods resulted in a two-phase prostaglandin release and a significant drop in leukocyte count, suggesting horses have a strong reaction to such endotoxins.
• Through repeated injections, the research found that subsequent injections elicited a smaller hormone response, suggesting a refractory or desensitized response over time—or in simpler terms, the body becoming ‘used’ to the toxin and responding less each time.
• A similar desensitization was observed during continuous low-dose infusion of the toxin.

Impact of Flunixin Meglumine

• The use of Flunixin meglumine, a drug that inhibits prostaglandin biosynthesis, was also examined in combination with the endotoxin. The research showed that this compound must be given early to counteract the effects of endotoxemia and prevent harmful impacts on pregnancy.

Conclusion

• The conclusion from the research is that horses demonstrate a notable sensitivity to endotoxins, and even a brief duration of exposure—around 30 minutes—is sufficient to instigate clinical symptoms and reproductive disorders, including potential abortion.