Author's note: Analysis of the effects of procedures and environmental stimulation on horse behavior is an important welfare topic in the equine industry. Relaxed and calm horses tend to be more tractable and willing to work with people, and not as readily provoked into displaying dangerous behaviors.
Examination of a mare’s gynecological tract is a frequent undertaking in veterinary medicine. At the 2016 International Society for Equitation Science, a study was presented that sought to determine stress responses to mares subjected to gynecological procedures, including rectal palpation and transrectal ultrasound [Ille, N.; Aurich, J.; and Aurich, C. Physiological stress responses of mares to gynecological examination in veterinary medicine. Journal of Veterinary Behavior, Aug 2016, vol. 43, pp. 6-11].
Stress responses were measured through salivary cortisol levels and parameters of heart rate and heart rate variability. The 21 mares used in the study had either had previous foals or were in their first breeding season. Examinations occurred at 6-hour intervals or 24-48 hour intervals. All but 13 mares had three exams; those 13 had four exams.
The results were favorable in that “no significant differences existed between experienced and less-experienced mares and among examinations 1 to 4. The lack of changes in heart rate and heart rate variability and only minor increase in cortisol release indicated that gynecological examination was not perceived as a major stressor by the mares.”