Rectal examination is a vital tool in equine medicine – both for the investigation of gastrointestinal problems such as colic and in the routine management of assisted breeding in mares.
It is, however, a technique not without risks for both the horse and the operator. Horses appear to be more at risk of serious consequences such as rectal tears compared to other species.
In research conducted at the University of Pretoria, Elize van Vollenhoven and colleagues assessed the stress response of mares subjected to rectal examination. These were Nooitgedacht pony mares that were accustomed to rectal examination.
The procedure (trans-rectal palpation by a veterinary student) lasted 20 minutes for each horse. Samples of faeces and saliva were collected before and after the procedure and tested for salivary glutocorticoids (sGC) and faecal glucocorticoid metabolites (fGCM) respectively.
The research team found no significant differences in median sGC concentrations before palpation and at 10, 40, and 70 minutes after palpation. Neither were there significant differences between median fGCM concentrations before and 26 hours after palpation.
The authors of the report conclude that student transrectal palpation of the reproductive tract in habituated mares did not activate the hypothalamic-pituitary-adrenal axis.
For more details, see:
Salivary Glucocorticoid and Fecal Glucocorticoid Metabolite Concentrations in Pony Mares During Transrectal Palpation of the Reproductive Tract by Veterinary Students
Elize van Vollenhoven, Catharina Cornelia Grant, Lizelle Fletcher, Martin Lance Schulman, Patrick Collin Page, André Ganswindt.
Journal of Equine Veterinary Science (2018) 70, pp 7-12