Ataxia is the incoordination which affects one or more limbs as well as the neck or body. This means that is a lack of communication between the nervous system and the body parts of the horse. Ataxia is not painful therefore he has no sense of the position and movement of affected areas.
The gait changes all the time when it comes to Ataxia. A leg might swing out to the side or a joint might overflex.
If he trips, an ataxic horse may be slow to correct himself and potentially fall. His trunk, neck or both might sway. He may tread on himself, or struggle to turn – or instead of crossing his legs underneath as he does turn, he stays rooted to the spot, rotating while his legs eventually catch up.
When documenting the severity of the problem, a grading system can depict it. Starting with zero for normal strength and coordination.
Certain conditions present at birth can cause ataxia. These include abnormal underdevelopment of the cerebellum and abnormal formation of the first and second cervical vertebrae.
Infectious disease can result in ataxia: viruses, such as the equine herpes virus-1 (EHV-1), which is endemic in the UK, and the exotic disease West Nile virus, which is becoming established in central Europe and likely to come to the UK at some point.
Reaching a diagnosis begins with consideration of the horse’s age and breed and a thorough examination of his history. Has he fallen, for example, or are there stinging nettles in his field?
A routine examination will assess factors such as heart rate, respiratory rate and temperature, to identify any other physical abnormalities that may contribute to or be part of the neurological problem.
A neurological examination then follows, comprising tests to identify the part of the nervous system that is affected. The disease may be focal – centred in one location or affecting multiple places.
THE prognosis for ataxia is variable, depending on the diagnosis. Sadly, many conditions affecting the spinal cord have a guarded to poor prognosis, due in part to a horse’s size and the safety concerns regarding him and his handlers.
Treatments, including surgery, are improving all the time. Repeated neurological examination and diagnostic tests can aid and guide decision-making, ensuring that equine welfare is always put first.
Extracted from Horse & Hound. Why might a horse become weak, wobbly or unable to stand?. https://www.horseandhound.co.uk/plus/vet-clinic/ataxia-explained-why-a-horse-might-become-weak-wobbly-or-unable-to-stand-hh-plus-742892. April 2021.