The Effect of Routine Postpartum Uterine Lavage on Endometrial Cytology, Culture, and Pregnancy Rates in Thoroughbred Broodmares.
Authors: Mitchell Anna R M, Scott Camilla J, Cheong Soon Hon, Carrigan Peter, Diel de Amorim Mariana, Collins Cameron D
Journal: Journal of equine veterinary science
Summary
# Editorial Summary Maintaining rapid rebreeding intervals in thoroughbred broodmares is economically critical for breeding operations, prompting investigation into whether routine postpartum uterine lavage—performed 3 days after foaling—could accelerate uterine clearance and improve fertility outcomes. This Australian retrospective study compared 32 mares managed with (2015) and without (2014) postpartum lavage protocols, collecting endometrial swabs via cytology and culture at both foal heat and second postpartum estrus before natural breeding. Whilst lavaged mares demonstrated significantly lower polymorphonuclear cell (PMN) counts on both foal heat and second heat swabs, indicating reduced endometrial inflammation, the procedure failed to lower bacterial culture rates or enhance pregnancy outcomes between groups. Notably, both lavaged and control mares showed higher positive cultures and PMN counts at foal heat, which resolved by second heat regardless of treatment—suggesting the early postpartum period represents a normal physiological window of endometrial inflammation rather than pathology requiring intervention. For practitioners, these findings suggest that routine postpartum lavage, whilst effectively modulating the endometrial inflammatory response, offers no clinically meaningful advantage in breeding efficiency or infection control compared to allowing natural postpartum involution.
Read the full abstract on PubMed
Practical Takeaways
- •While routine postpartum uterine lavage reduces endometrial inflammation (PMNs), it does not eliminate bacterial contamination or improve pregnancy outcomes, suggesting it may not be necessary for all broodmares on well-managed farms
- •Consider that endometrial inflammation naturally resolves by second postpartum estrus regardless of lavage intervention, so selective rather than routine use may be more cost-effective
- •Endometrial cytology and culture at foal heat do not predict pregnancy success at the second estrus breeding, so their use as decision-making tools for intervention may be limited
Key Findings
- •Routine postpartum uterine lavage at 3 days postpartum significantly reduced polymorphonuclear cells (PMNs) in endometrial cytology at both foal heat and second postpartum estrus compared to control year
- •No significant difference in bacterial culture rates between lavaged and control groups at either foal heat or second postpartum estrus
- •Positive culture and cytology rates were significantly higher at foal heat than at second postpartum heat in both years
- •Uterine lavage did not improve pregnancy rates despite reducing endometrial inflammation markers