Ataxia – a lack of voluntary muscle co-ordination – can be a death sentence for a horse. Now, researchers from the University of Copenhagen and the Royal Veterinary College in Britain have shown that there can be marked disagreement among veterinary surgeons about whether or not a horse is ataxic.
Veterinarians and horse owners can often put mild cases down to lameness.
At least one in 100 horses at some point in its life will lose the ability to control its gait as a result of ataxia.
Once found to be ataxic, the horse is often put down, or undergoes an expensive operation with questionable results.
Ataxia caused by Wobbler syndrome affects one in 100 horses, and is one of the greatest sources of missed training days and frustration for horse owners and veterinarians alike.
A trip to the veterinarian may prove fatal to a horse, even if it is not necessary to put the animal down. In Europe, if a horse is found to be ataxic, which is most often due to the disease, wobbler syndrome, it is likely to be put down immediately.
If a horse suffers from the disease, putting it down can be a necessity, as the animal can be dangerous to ride and handle. But the British and Danish researchers have shown there is marked disagreement among experts about when a horse is ataxic and the severity of the ataxia.
It is particularly a problem if the ataxia is subtle, as it makes it more difficult to assess, they said.
“It is a problem for both the horse and the owner if the specialists disagree,” said veterinarian Emil Olsen, from the Department of Large Animal Sciences, who headed up the new research.
“A horse which could potentially recover might be put down, as an ataxic horse eventually becomes a hazard to the owner due to the risk of a fall during riding or handling,” he says.
The results were recently published in the Journal of Veterinary Internal Medicine.
Wobbler syndrome occurs due to pressure on the cervical spinal cord, which can be diagnosed in humans and small animals by MRI or CT scans – but there are no scanners with a diameter large enough to accommodate a horse’s neck and shoulders.
The foundation of the veterinarian’s assessment is therefore the clinical examination of small changes and irregularities in the horse’s gait.
Olsen said: “In this study, specialists in the areas of large animal internal medicine, specialists in equine surgery, and residents evaluated the gait during a neurological examination of 25 horses, and then videos of the horses.
“They completed a questionnaire, and based on their responses we could see that there was wide disagreement on whether or not they believed a horse was ataxic, and particularly on the severity of the ataxia.”
Horse owners and veterinarians often assumed horses with mild ataxia were mildly lame, he said, allowing ataxia to progress to the point of sudden falls during riding or handling.
If the disease is discovered when the horse is a foal, treatment options can include restrictive feeding, and at all ages there is a surgery to stabilise the neck by fusing the cervical vertebrae.
For horses with ataxia caused by articular process joint (facet joint) osteoarthritis, injecting steroids into the joint can improve the horse’s condition for a period of time.
“We hope that our findings will lead to the establishment of clearer definitions for what constitutes normal and abnormal gait patterns in horses, and the relationship between spinal cord disease and ataxia,” Olsen said.
“This could lead to greater agreement among specialists and practising veterinarians. The current disparity also raises the need for quantitative diagnostics, using equipment that can measure the horse’s movements in detail.”