Comparative analysis of vocalizations of thoroughbred mares (Equus caballus) between estrus and diestrus.

This research investigates the variation in vocalizations of thoroughbred brood mares during estrus and diestrus, and how this could be used to distinguish between the two reproductive stages.

Objective and Methodology

• The main aim of the study was to explore differences in vocal behaviors between mares in estrus (a stage of the reproductive cycle when the mare is receptive to mating) and diestrus (a phase when the mare is not sexually receptive).
• The researchers used a sample of 89 thoroughbred brood mares who were exposed to a teasing procedure for 3 minutes while their reactions, particularly vocalizations, were recorded.

Findings

• The results showed that a higher percentage of mares in diestrus emitted calls (78.6%) towards an approaching stallion as compared to those in estrus (56.5%). This suggests that mares in diestrus are more likely to verbally respond to an approaching stallion than those in estrus.
• The study specifically analyzed the squeals of 25 mares in estrus and 22 mares in diestrus towards an approaching stallion.
• The analysis of these vocalizations showed that the duration and the third formant (a parameter in acoustics related to frequency) of the mares’ calls could be potential distinguishing parameters between estrus and diestrus.

Significance of the Study

• The research adds to the body of knowledge concerning the behavior of thoroughbred brood mares during their reproduction cycle.
• The findings could be valuable in animal husbandry and veterinary medicine, as it offers a potential non-invasive method to monitor the reproductive cycle of mares through understanding and observing their vocal behaviors.