Post-breeding intrauterine infusion of dehydrated amnion product produces similar pregnancy rates as antibiotics

Abstract

Results of two large studies by Pascoe and then Pycock first demonstrated the value of postbreeding treatments in mares. When combined, these authors analyzed pregnancy data from over 2200 mares. In their studies, those treated with antibiotics (ABX) and plasma or oxytocin had a higher conception rate than any other group. However, a Cochrane-style review by Barter and Barrelet (Veterinary Evidence 2018;3(1):1-11. of these and numerous smaller studies didn't convincingly confirm a treatment benefit of any specific therapy. In a 2-part multicenter clinical study involving three veterinary practices, we aimed to determine whether postbreeding intrauterine (IU) infusion with a novel dehydrated amnion-derived allograft1 (DAA) would enhance pregnancy rates in a clinical setting. To achieve this, we first performed a targeted prospective study of postbreeding IU DAA compared to ABX in first-cycle barren Thoroughbred mares. Sixty mares that had either failed to get pregnant on two or more cycles in the previous year or which lost a pregnancy were randomly assigned to either a DAA or ABX treatment group at the onset of the breeding season. Mares with no bacterial growth and <5mm IU fluid prior to breeding were included in the study and administered IU either1 vial LAP diluted in 60 ml LRS or 7.2 million IU procaine penicillin and 600mg gentamicin, extended to 60 mL with LRS within 24 hours postbreeding. Mares with intra-uterine fluid were lavaged or received oxytocin based on clinical presentation. Statistical analysis was performed using a publicly available chi square calculator with significance set at P<0.05. There was no difference in the first cycle pregnancy rate of the DAA group compared to ABX (65% vs 64%, respectively). Based on these results, clinicians used DAA as a component of their reproductive treatment protocols during the 2022 breeding season. Retrospective analysis of over 500 breeding cycles from 386 mares was performed using the same methods as above to compare pregnancy rate in cycles with no treatment, DAA alone, DAA/lavage, ABX alone and ABX/lavage based on the clinical judgement of the attending veterinarian. Pregnancy rates were not statistically different between groups (69%, 57%, 73%, 64%, 62%), however pregnancy rates were numerically highest in cycles treated with DAA/lavage. The above data suggest that the use of IU DAA is safe and support its use as a postbreeding infusion to optimize pregnancy rates in broodmares.