The prevalence of recurrent airway obstruction among older horses and ponies is considerably higher than the number of diagnosed cases, evidence suggests.
The allergy-based respiratory disease can cause a chronic cough, nasal discharge, and respiratory difficulty, with episodes most likely when susceptible horses are exposed to common allergens from the likes of hay, bedding straw or from a stable environment.
British researcher Dr Jo Ireland and her colleagues said respiratory disease was a common cause of ill health in older horses, with a higher prevalence as horses aged.
However, owners frequently did not attribute the signs to disease and may not seek veterinary attention.
The researchers set out to estimate the prevalence of recurrent airway obstruction among older British horses and ponies using a risk-screening questionnaire and identifying factors associated with the condition.
Owners of geriatric horses and ponies enrolled in a previous study were sent a postal questionnaire asking about horse management, preventive healthcare, and respiratory-specific clinical signs.
They received back useable data for 285 horses and ponies, with an average age of 23.3.
The study team, in a research presentation to delegates at the recent British Equine Veterinary Association (BEVA) Congress, found that coughing, at 27%, was the most prevalent owner-reported clinical sign within the previous year.
The apparent prevalence of recurrent airway obstruction among the study group was 20.7%, which was nearly double the 10.5% of horses and ponies reported to have been veterinary-diagnosed with the condition (the average age of diagnosis was 13).
Factors associated with an increased risk of recurrent airway obstruction were ridden exercise four or more days a week compared to no exercise; residing on a farm compared to living on the owner’s home premises; and having had a respiratory infection within the past 12 months.
Ireland and her fellow researchers said their risk-screening questionnaire showed that the prevalence of the condition was considerably higher than the proportion of animals previously diagnosed with it.
“This suggests under-diagnosis of respiratory problems in geriatric horses, much of which may be unrecognised or undiagnosed recurrent airway obstruction.”
Risk factors identified differed from those previously reported for the general equine population, they said.
The study was funded by the Animal Health Trust.
A summary of their work has been published in the Equine Veterinary Journal, as part of the proceedings from the BEVA Congress.
Ireland, J.L., Christley, R.M., McGowan, C.M., Clegg, P.D. and Pinchbeck, G.L. (2015), Prevalence of and Risk Factors for Recurrent Airway Obstruction in Geriatric Horses and Ponies. Equine Veterinary Journal, 47: 25. doi: 10.1111/evj.12486_57
The abstract can be read here.