Simple horse respiratory tests developed

The two non-invasive methods could potentially be used by vets to screen for horses with respiratory problems and to assess whether a horse being treated for a respiratory condition is improving.

The Horse Trust-funded research, led by Professor Sandy Love at the University of Glasgow, developed a technique that allows vets to easily monitor the frequency of coughing in a horse over a long period of time with 100 per cent sensitivity and accuracy.

Cough frequency is known to be a sensitive measure of respiratory inflammation, but manually monitoring the number of coughs for an hour each day is not cost-effective.

Love, who is professor of equine clinical studies at the university, discovered that a digital recorder attached to a horse's headcollar could be used to gather data, which could then be quickly analysed.

One hour of coughing could be analysed within three minutes by manually examining a graph of the audio file. This analysis time could be sped up further in a commercial setting by automating the analysis with computer software.

The audio file analysis was found to be 100% sensitive and specific - picking up every cough and perfectly distinguishing coughs from other noises, such as the horse stamping its feet, or a tractor starting.

The research also led to the development of a device, built with components readily available from a do-it-yourself store, that can be attached to a horse's head to capture its breath and condense the liquids within the expired air.

This was used to analyse whether any substances in exhaled breath could be used as indicators of respiratory inflammation.

Love found that the most useful indicator was the pH of the liquid condensed from the expired breath - the pH of the exhaled breath condensate was higher in horses suffering from respiratory inflammation.

He also monitored the level of various gases within the expired breath - carbon monoxide, nitric oxide and ethane - but found no significant correlation with respiratory inflammation.

"Both of these techniques could easily be commercialised to enable vets to quickly and ethically monitor respiratory inflammation in horses," said Love.

"They could also result in improved treatment of respiratory conditions, as vets will be able to objectively assess which treatments work or don't work for a particular horse."

Both techniques are well tolerated by horses and ponies.

Respiratory problems are common in horses, with various surveys reporting that respiratory airway inflammation occurs in 10 to 50 per cent of competition and pleasure horses.

Respiratory problems not only reduce the quality of life of the horse, but are also a common cause of exercise intolerance.

At present, the only techniques available to monitor respiratory inflammation are invasive, such as endoscopy.

Due to being invasive, such techniques cannot be used frequently, so vets have had no way of objectively assessing whether a particular respiratory treatment or management technique is working.

Paul Jepson, chief executive and veterinary director of The Horse Trust, said the trust was delighted the research led to new, non-invasive ways of monitoring respiratory inflammation in horses.

"These techniques could have a major impact on horse welfare by improving the diagnosis and treatment of this common condition," he said.

The Horse Trust, founded in 1886, is the oldest horse charity in Britain.

The research project led by Love is ongoing. His research team recently submitted a paper entitled "The measurement of exhaled breath condensate pH in horses" to The Veterinary Journal. They have also submitted a paper entitled "Validation of a method for the objective assessment of coughing in horses" to Research in Veterinary Science.

The research team includes Kris Hughes, Tim Parkin, Marco Duz, Mike Cathcart and Andrew Whittaker. Previous breath analysis projects have involved Cathy Wyse, David Murphy, David Sutton and Dominic Mellor.