Using oxytocin to prolong diestrus
Researchers have found a promising alternative for long-term suppression of estrus—and aberrant behavior—in mares.
Apr 01, 2014
It's common for mares to display different and even aberrant behaviors during estrus, including attitude changes, stubbornness, "horsing" and potentially impaired performance.
Equine practitioners have explored a variety of techniques to suppress estrus or extend the diestrus period, therefore limiting problematic behaviors and maintaining performance, especially for racing horses in training. Historically, an orally active exogenous synthetic progestin (altrenogest) has been administrated effectively to mares at a dose of 0.044 mg/kg/day to accomplish estrus suppression. Though this method is considered the gold standard for suppressing estrus in mares, the expense of supplemental progesterone, the need for daily administration and safety concerns over the use of steroids in performance horses and for personnel during handling and administration have caused veterinarians to look for alternative techniques.A promising alternative
A common method of prolonging CL function and suppressing estrus is insertion of a glass or plastic intrauterine ball. But this methodology comes with drawbacks and concerns, primarily anecdotal reports of complications with the intrauterine marbles. While Vanderwall was at the University of Pennsylvania's New Bolton Center, one mare with two marbles in her uterus was referred for treatment. The current owner was unaware of the marbles, and upon removal, the glass balls showed pitting on their surfaces from prolonged contact in the uterine lumen. Others have reported glass marbles fragmenting in the uterus.
With these reported complications, Vanderwall says he felt the procedure warranted serious reconsideration, and he began his search for alternatives.