Induction of parturition in the mare with prostaglandin F2 alpha.

This study investigates the use of the hormone prostaglandin F2 alpha (PGF2 alpha) to induce labor in mares of Thoroughbred and Quarter Horse breeding. The researchers monitored the effects on both the birthing mares and their offspring, noting any side effects and the viability of the newborn foals.

Objective of Study

The aim of this research was to evaluate the effectiveness of prostaglandin F2 alpha (PGF2 alpha) for inducing parturition (birth) in horses and to assess any impacts this procedure could have on the overall health and viability of the foal.

Experiment Design

• Two experiments were carried out using a total of 31 Quarter Horse and Thoroughbred breeding mares.
• In the first experiment, five mares were given a 5 mg dose of PGF2 alpha on the 338th day of gestation.
• In the second experiment, seven mares given 3 daily injections of 10 mg estradiol cypionate (ECP) on gestation days 326, 327 and 328 were infused with PGF2 alpha at a rate of 1.3 mg/hr for 24 hours or until parturition occurred.

Results and Effects

• Injection of PGF2 alpha induced labor in a majority of mares studied. Three out of five mares in the first experiment and four out of seven mares in the second experiment foaled within hours of being treated.
• Side effects from the hormone treatment were observed, including sweating, hypothermia, increased respiration rate, and transient diarrhea, but these were temporary.
• The treatment did not negatively affect the viability of the foals born as a result of induced labor.
• However, it was noted that some foals born 12 days prior to expected parturition displayed weaker pasterns (a part of a horse’s lower leg) when compared to those of control mares.

Conclusion

The findings indicate that using prostaglandin F2 alpha to induce labor in mares is overall effective, with temporary side effects to the mares and no significant harm to the foals. Some caution may be necessary when inducing parturition significantly early, as it may cause the resulting foals to have slightly weaker pasterns.