FACT SHEET – Feeding Horse and Ponies Prone to Cushing’s/PPID

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What is Cushing’s Disease?

Cushing’s Disease, also known as Pars Pituitary Intermedia Dysfunction (PPID), is a hormone imbalance which is commonly caused by enlargement of the pituitary gland. The pituitary gland is a small gland at the base of the brain and controls many body processes through the secretion of different hormones. In horses that suffer from PPID, the middle section of the pituitary has become enlarged which causes an increase in the production and release of certain hormones, one of which is ACTH (adrenocorticotrophin hormone). This hormone makes its way to adrenal glands around the horse’s kidneys and causes them to over produce cortisol (a type of steroid). It is the over production of this steroid that causes the classic Cushing’s/PPID symptoms. 

Cushing’s disease has become increasingly diagnosed over recent years, perhaps as like people, horses are now living longer. Although it can affect younger individuals, Cushing’s generally affects older horses and ponies; ponies often seem to be more prone to this than horses but there isn’t currently a particular breed or sex that seems to be more predisposed to the condition

Cushing’s disease has become increasingly diagnosed over recent years, perhaps as like people, horses are now living longer. Although it can affect younger individuals, Cushing’s generally affects older horses and ponies; ponies often seem to be more prone to this than horses but there isn’t currently a particular breed or sex that seems to be more predisposed to the condition

What are the Symptoms of Cushing’s/PPID?

There are a number of symptoms that horses/ponies prone to Cushing’s may exhibit, and individuals may show one or several of the symptoms below:

  • Long/thick/curly coat
  • Excessive sweating
  • Pot belly
  • Significant loss of topline
  • Increased thirst and appetite
  • Laminitis
  • Abnormal fat distribution particularly above eyes/on the crest of the neck
  • Lethargy
  • Increased predisposition to infection/worm burden

The Importance of Nutrition in the Management of Cushing’s

It is important to remember that the diet you previously fed will not have caused Cushings to develop, but equally, diet cannot cure the condition either. Indeed, unfortunately there is currently no known cure for Cushing’s so whilst medication and veterinary support are important, careful management and the correct nutrition is also key in ensuring your horse/pony lives as normal a life as possible. As a general rule, horses prone to Cushing’s should be fed as though they are prone to laminitis. This means that all meals should be kept as low in starch and sugar as possible, so avoiding any traditional cereal-based mixes or cubes. Consider using a fibre-based bucket feed to provide calories from digestible fibre rather than starches and sugar and ensure that correct levels of minerals and vitamins are also provided, either in a high fibre complete feed, or as an additional supplement.  Monitoring these horse’s ‘fat covering’ regularly is really important. Being overweight can place oxidative stress on the horse’s body, and this stress, over a period of time, may itself cause some of the symptoms of the condition. Additionally, being overweight may contribute to the horse developing insulin resistance; PPID can cause this to become worse. 

Forage will play a large part in the management of horses and ponies prone to Cushing’s. If hay is being fed, this ideally should be tested to ensure it contains a WSC (water soluble carbohydrate) level of less than 10%. However, this can be both costly and time consuming as hay can vary a huge amount from bale to bale. Some varieties of bagged forage are safe to feed to horses and ponies prone to Cushing’s but ensure you choose the correct calorie option for your horse or pony’s requirements. In an ideal world we all know our horses should have ad lib access to a fibre source of some sort, however, this is not always an option for horses and ponies prone to Cushing’s who may hold their weight well. Feeding a low calorie, low starch and low sugar bagged forage in small holed or double-netted haynet and splitting their allowance up into as many small meals as possible will all help to ensure they’re never stood for too long without anything to eat. Remember that your horse will consume large amounts of calories if turned out in a field full of grass, so restricting their intake is key. There are various techniques including the use of grazing muzzles and strip/track grazing. Try to ensure your grazing has been properly managed for horses and isn’t very rich, fertilised cattle grazing, also ensure that access is restricted after a sharp frost, particularly when followed by a bright sunny morning as grass fructans (a type of carbohydrate thought to increase the risk of laminitis) are likely to be higher at this time. 

Although somewhat less common, some horses suffering from PPID may require a little extra help maintaining or gaining weight. As already discussed, good quality forage should always form the basis of the diet, but if bucket feeds are required it is particularly important to remember the “little and often” rule. This is so ensure we limit any insulin response as much as possible and therefore reducing the chance of laminitis (even underweight individuals may have a higher predisposition to an attack).

Top Tips for Feeding Horses and Ponies Prone to Cushing’s

  • Try to keep your horse at a healthy weight.
  • Choose fibre-based feeds that are guaranteed to be low in sugar and starch.
  • Ensure you supply a balanced diet – recommended amounts of vitamins and minerals are essential.
  • Feed little and often to avoid peaks and troughs in blood glucose.
  • Keep a careful eye on your grazing. Horses often consume far more calories than we think whilst turned out.