Oral Conflict Behaviour is a Potential Indicator of Oral Lesions in Dressage Horses

Veterinary

Health Care

-- This study was conducted by Janne Christensen and Mette Uldahl and presented at the 2024 ISES Conference

Oral Conflict Behaviour is a Potential Indicator of Oral Lesions in Dressage Horses

Summary

A good life for sports horses requires that they are trained and competed without discomfort and pain from ill-fitting equipment or inappropriate training. However, many sports horses have oral lesions, which is a source of pain and a welfare concern.

This study found that dressage horses with oral lesions showed more oral conflict behaviour (mouth opening) during a dressage competition compared to horses without lesions. Increased awareness of behavioural indicators can improve sports horse welfare.

The Study

The welfare of sports horses is debated both within and outside the horse community. For example, the frequent occurrence of oral lesions (ulceration) poses a threat to a good life for competition horses. Lesions may be caused by inappropriate training methods and ill-fitting equipment.

Increased knowledge of behavioural signs of discomfort in horses can increase awareness by riders, trainers, officials, and competition judges, which is a first step to reduce the occurrence.

This study included 11 warmblood dressage horses competing at upper national level (Intermediaire I; 5 mares, 2 stallions and 4 geldings; ridden by 8 female and 3 male riders). The horses were randomly selected (from a total of 22 horses) for a routine inspection for oral lesions immediately after leaving the dressage arena at competition. The inspector made the horse open its mouth with the fingers and examined the oral commisure, the bar and cranial part of the buccal mucosa from both sides.

Five of the 11 horses were found to have ulceration of the skin and/or mucosa at one or both commissures of the lips. The pathology of the lesions was consistent with pressure wounds.

An experienced observer who was blind regarding the outcome of the oral examination, scored oral conflict behaviour (e.g. opening of the mouth, i.e. with clear separation of the teeth) in the 11 horses from official video recordings available online from the event. The frequency of mouth opening ranged from 8 to 59 during the approx. 5.5 min dressage program. Due to the position of the official cameras, the mouth of the horses was only visible for approx. 2/3 of the program for all horses.

Horses with oral lesions had a significantly higher frequency of mouth opening compared to horses without oral lesions (t-test, mean ±SEM; lesions: 34.6±6.7 vs. no apparent lesions: 12.2±2.4, t(9)=3.4, p=0.008). The frequency of other conflict behaviours did not differ significantly between the groups (e.g. tail swishing: MWU-test, median [25;75%]; lesions: 25 [14;27] vs. no apparent lesions: 10 [6;24], U = 7.0, p=0.18).

It is concluded that oral conflict behaviour may be a useful indicator of oral lesions. Further studies are needed to investigate behavioural signs of discomfort in riding horses, as behaviour can be an early predictor of compromised welfare. Increased awareness of subtle behavioural signs is an important first step towards improved sports horse welfare.