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Motor Neuron Disease In Horses

What are the signs of motor neuron disease (MND) in horses? How is MND diagnosed in horses? MND  is a condition in which sporadic degeneration of muscle nerves in mature horses leads to muscle weakness and wastage. If you suspect your horse may have MND, it is important to know whether or not your horse needs to visit a veterinarian, or if the solution may be taken care of without the extra expense. Online Experts are available to provide accurate information. Read below where Experts have answered questions for other horse owners.

What are the signs of MND in horses?

In the beginning of MND, the most common signs of the disease are trembling or muscle fasciculations (looks like worms wriggling under the skin), frequent shifting of weight on the hind legs, excessive lying down, muscle wasting and abnormal sweating. These horses have a normal appetite and are not lame. As the disease progresses, the chronic signs more likely to be seen are camped under stance (four legs drawn in under the body), an elevated tail, a lower than normal neck carriage, and abnormal brown pigment around the retina of the eye. A veterinarian would need to look through an ophthalmoscope to see this, (it is reportedly present in about 30% of cases), fatigue, tying-up, or Stringhalt-like episodes, and poor performance. Not all horses with MND will show all signs.

How is MND diagnosed in horses?

The diagnosis of this disease involves a muscle biopsy of a muscle near the tail head, or biopsy of the ventral branch of the spinal accessory nerve (more complicated). These procedures catch 90% of cases and find only about 10% false positives. Bloodwork can also be helpful, often muscle enzymes, such as CK and AST/SGOT will be increased (although primary tying up can also do this) from muscle damage, and in most cases Vitamin E levels are low. The vet will need to send blood to a specific lab to check the Vitamin E levels as they are not included in a usual CBC of chemistry done at most clinics.

What is the cause of MND in horses?

The cause of the disease is postulated to be a Vitamin E deficiency, and hence the relation of pasture grazing in some horses, but no one knows for sure if there are other causes.

Could a horse’s sweating, tying up, tremors and muscle degeneration be a sign of MND?

Yes, these symptoms resemble MND, but without a veterinarian visit it is impossible to properly diagnose. The horse needs the proper diagnostic tests to determine the exact cause of the symptoms. It has been described as similar to Lou Gehrig’s disease in people. This disorder is uncommon and often misdiagnosed.

Is MND the cause of a 24-year-old horse to have a sudden onset of crab walking in hindend?

Case Details: Symptoms get better with rest and worsen with movement. The horse eats well. The horse rolls every day. When massaging, the horse is very sensitive in the neck, shoulders and girth box.

MND is unlikely because extreme muscle wasting is usually associated with this condition. The most common reason for hind end ataxia (drunken gait) in a horse is Equine Protozoal Myeloencephalitis. The other disease, although more common in drafts and quarter horses, is Equine Polysaccharide Storage Myopathy. The fact that the horse improves with rest, tilts the scales toward a diagnosis of Equine Polysaccharide Storage Myopathy. The other much rarer cause could be a tumor of the spine or nervous system. The horse should be tested for Equine Protozoal Myeloencephalitis first (as this is most likely) and if the test comes back negative, the horse should have a muscle biopsy to look for Equine Polysaccharide Storage Myopathy.

Can fear in a horse cause the horse’s hindquarters to tremble, or is this a sign of MND?

Yes, horses may tremble from anticipation or fear, but this is usually very short-lived. MND can also cause muscle trembling due to a nerve problem, but typically these horses have other physical signs of a problem.

What is the treatment for MND in horses?

At the present time, there is no specific treatment for MND; but high doses of oral Vitamin E supplements and increased pasture turn out on green grass, have proved to be helpful in many cases.

Horses are an important part of many people’s lives. If your horse is in pain or has unexplained symptoms, it is important to know where to turn for accurate, reliable answers to all your questions. Online Experts can help and put your mind at ease regarding your horse’s pain or symptoms. If you have other questions regarding Motor Neuron Disease, online veterinarian Experts can assist you day or night, at your convenience.

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