Evaluation of androgenized mares as an estrus detection aid.

The research paper investigates the use of pony mares, which have been treated with anabolic steroids to develop stallion-like behavior, as a method for detecting estrus in other mares. The paper concludes that although some estrus mares can be identified based on their response to the treated mares, the method is only partially successful.

Background

• The research was borne out of the need for reliable methods of estrus detection in mares, a crucial part of equine breeding management.
• Ten pony mares that had been treated with the anabolic steroid boldenone undecylenate to develop stallion-like behavior were used in this study. This treatment was administered once a week for 12 injections.

Methodology

• The researchers evaluated the mares’ effectiveness in detecting estrus through across-the-fence trials and 10-minute pasture trials.
• In the across-the-fence trials, androgenized mares were not successful in eliciting signs of estrus or diestrus.
• In the pasture trials, each androgenized mare was placed with a group of 10 cycling mares. Of these, six were in estrus. Seven out of ten androgenized mares managed to elicit estrous behavior from one or two of the mares.

Results and Conclusion

• Further observations of the androgenized mares amongst a larger group of 21 cycling mares indicated that around a third of the mares in estrus could be identified based on their response to the androgenized mares.
• The partial success of the method suggests that using androgenized mares may indeed aid in estrus detection. However, the variability in results also implies that other factors may be at play, and the effectiveness of this technique may be dependent on additional contributing factors not explored in this study.