If horses experience mounting as unpleasant for whatever reason, they can already become stressed at the sight of the mounting block. Some horses show this very clearly in their behaviour and for others it is in the details. Reading the facial expression can help you determine if the mounting block is causing stress. Katarzyna Olczak, PhD, of the Equine Breeding Division of the National Research Institute of Animal Production, in Balice, Poland, has researched this. 

For this study, multiple facial photographs of 11 horses, ages 6 to 12, were taken while being led to the mounting block and standing next to it. They photographed each horse with and without a saddle. Using the Horse Grimace Scale (HGS), the researchers determined facial expression scores for each horse in each situation. The scores were based on the presence of lowered ears, tense masticatory muscles and muzzle and dilated nostrils, and eyelid covering more than half of the eye. To validate their results, the team had two independent observers evaluate the photos. 

The observers found that, between being led to the block and standing next to the block, horses’ facial expression scores changed dramatically from a non-stressed state to a stressed state. Whether the horse was saddled didn’t matter. What clearly mattered, however, was the presence of the mounting block itself. This could suggests that some horses in this test group have negative associations with the mounting block, possibly related to unpleasant mounting and/or riding experiences.