Oestrus and fertility following progestagen treatment of mares showing clinical evidence of early pregnancy failure.

The research article investigates the effects of progestagen treatment on mares exhibiting signs of early pregnancy failure. The study found no significant impact on pregnancy continuation and future conception rates, with no increase in twin or deformed foals.

Research Methodology

• The researchers selected 383 mares demonstrating signs of early fetal resorption, occurring between 20 and 60 days post-mating. This condition is indicated by a reduction in progesterone levels and can lead to early pregnancy failure.
• Among these, 217 mares received a single injection of 200 mg of CAP, a synthetic progestagen. Progestagens are substances that maintain pregnancy by imitating the action of the natural hormone, progesterone.
• The remaining 166 mares did not receive any treatment and were used as control for the experiment.

Findings

• The treatment did not have any observable effect on the progress of pregnancy. It neither improved the chances of pregnancy continuation nor did it have any adverse impact.
• Post-loss of the conceptus (embryo and associated tissues), higher conception rates were observed in lactating mares compared to non-lactating ones. This suggests that lactation may have some influence on the ability to conceive following a failed pregnancy.
• The research also tracked any abnormalities in the offspring born post treatment. The observations showed no increase in the incidence of twin foals or those with deformities among the treated animals. This suggests that the treatment likely does not adversely affect fetal development.

Conclusion

The findings indicate that administering progestagen to mares experiencing early pregnancy failure does not significantly affect the continuation of pregnancy nor occurrence of deformities in foals. The research provides substantial guidance for veterinary practitioners when considering synthetic progestagen treatment in early-pregnancy-failure mares. However, its role does not seem to intervene positively or negatively with the natural course of pregnancy, and additional research is needed to identify effective interventions for mares with early pregnancy failures.