Causes of abnormally long coats in ponies

An abnormally long coat in a pony is the majority of cases is a symptom of the onset of Cushings disease. This is a metabolic disease that most commonly affects ponies who are suffering from a problem with their endocrine (hormonal) system. Another sign that a pony has cushings is abnormal hoof development.

Feeds for Cushings Disease

One of the most important considerations when feeding a horse with Cushing's disease is ensuring the horse is receiving a balanced, low NSC diet with good levels of quality protein, vitamins (especially vitamin E) and minerals (including chromium). Using the recommended dose rate of a good quality vitamin and mineral supplement will help to ensure these requirements are met.

Avoid feeds that change post-feeding blood glucose and insulin concentrations and that could cause insulin resistance

Horses suffering with Cushing's disease lose much of their ability to control the levels of glucose and insulin in their blood. The ingestion of sugars by a Cushing's affected horse causes abnormally high rises in blood insulin levels that can remain elevated for long periods of time. A recent study (Asplin et al. 2007) has found that high levels of circulating blood insulin can cause laminitis, which may explain why horses affected by Cushing's disease are especially prone to laminitis.

Since insulin resistance can be associated with Cushing's disease, any feeds that cause a significant increase in blood glucose and insulin concentrations post-feeding, such as high starch cereal grains, cereal grain by-products such as pollard and bran, molasses and improved pastures or pastures that are stressed or growing under sunny but cold conditions, should be avoided. Feeds and forages that are low in sugars and starches (<12% NSC) and high in digestible fibre and/or oil, that provide readily available energy, without changing blood glucose or insulin levels are desirable for a horse with Cushing's.

Selecting Suitable Feeds.

Forages such as mature, stemmy grass hay and mature lucerne hay are suitable for most horses with Cushing's disease, though to be on the safe side you should have your hay tested by a laboratory such as Dairy One to make sure the NSC content is less than 10-12%.

The Stance Equine Feeding System outlines several feeds with low NSC. These include

CoolFibre contains a low NSC (7%), high level of digestible fibre, and MCT
CoolStance contains <12% NSC, which reduces the amount of fermentable sugars that can cause an increase in blood glucose and insulin.
CoolStance and PowerStance contain MCT in the coconut oil.

What is Equine Cushing's Disease?

Cushing's disease is a disease of the endocrine system and is caused by an abnormality in one of the endocrine glands, the pituitary, which is found at the base of the brain, causing production of large amounts of ACTH, which in turn causes the production of excessive amounts of the hormone cortisol. Cortisol is a natural steroid hormone produced by the adrenal cortex, and is required in the body to regulate blood pressure and cardiovascular function as well as control the body's use of proteins, carbohydrates, and fats. However the continuous and excessive production of cortisol, is harmful. Cushings Syndrome appears in horses from 12 years and older, and also appears in geriatric and senile horses. It is considered that Cushings is part of the ageing process.

Do you Think your Horse has Cushings Disease?

Increased appetite, which can be combined with weight loss.
Insulin resistance (not always)
Increased susceptibility to laminitis
Abnormal fat distribution, with a cresty neck and fat deposits over the back and tailhead, and the appearance of bulges above their eyes
Excessive thirst, excretion of an unusually large volume of urine, profuse sweating
A pot bellied appearance and loss of topline muscle
A thick wavy hair coat in the winter that fails to shed before summer
An increased susceptibility to infection; and
Lethargy

Feeding a Horse with Cushing's Disease

The management of a horse with Cushing's disease requires a holistic approach involving environmental management, the use of drug therapy (talk to your vet about this) and balanced nutrition. Good feeding practices can go a long way to preventing serious complications like laminitis and enhancing the quality of life for a Cushing's horse

Use Good Feeding Management Practices

Because Cushing's horses are particularly sensitive to dietary changes, always introduce any new feeds and forages (especially lucerne) into the diet slowly. Feed them in small meals and always make sure they have constant access to a salt lick and clean fresh water. And finally, manage their weight carefully as excess body fat will make their problems with insulin resistance worse.

The Final Word

Feeding a low NSC diet is the key to managing a horse with Cushing's disease. Stay well away from anything that contains soluble sugars and starches (including processed feeds that contain any sort of grain or grain by-product) that are more than 10-12% NSC and instead use feeds that contain fats and digestible fibre. Adhere to the good basic principles of feeding a balanced diet, feed little and often, and make any dietary changes very slowly as outlines in the Stance Equine Feeding System. Most horses with Cushings disease are prone to laminitis, and of feeding a low NSC feed may help offset the added effects of laminitis. This will go a long way to maintaining a horse with Cushing's disease in good health