Essential pet advice with vet Jo Gourlay

Share this article

Over the next few articles we have a look at two equine conditions that are easily confused, Pars Pituitary Intermedia Dysfunction (PPID), which is the more correct term for the condition known as Cushings’s Disease, and Equine Metabolic Syndrome (EMS).

These endocrine (hormonal) conditions are remarkably common and are often a contributory cause of laminitis, among other problems. Given that the laboratory test to check for Cushing’s Disease is free until November 30, it’s worth knowing about the diseases so you can work out if it’s worth discussing testing with your vet.

We start with PPID, a condition primarily seen in ponies over the age of 15. Larger equines do also get the condition and it maybe that the higher representation in ponies is at least partly attributable to the fact ponies generally live longer. It’s thought that up to 30% of aged horses suffer from the condition and this risk directly increases with their age to the point that the majority of horses in their late 20s and 30s are likely to be affected. The classic signs are repeated bouts of laminitis (an inflammatory condition of the feet), despite efforts being made to prevent it; an abnormally long, thick and overgrown coat that is retained longer than expected going into the summer; an increased thirst and urination; increased sweating; chronic infections (due to a weakened immune system); and behavioural changes such as depression and lethargy.

Another, perhaps more subtle, sign is a redistribution of the fatty deposits on the body and loss of muscle condition. This can result in a pot-bellied appearance and a fatty bulge above the eye where there is normally a depression.

The condition is caused by over-activity in part of the pituitary gland (a small gland located at the base of the brain). This gland is responsible for a number of important functions such as production of a number of hormones, which includes one called ACTH that stimulates the adrenal glands (near kidneys) to produce cortisol, the body’s endogenous steroid.

The increase in the hormones produced causes an imbalance which results in the clinical signs seen. There are a number of different tests available to aid in diagnosis of PPID but the clinical signs, especially the coat changes, are often enough for a presumptive diagnosis.

The test being offered free of charge is arguably regarded as the most reliable and checks for the level of ACTH in the blood.

PPID is progressive and there is no cure but medication is available with a drug called pergolide being most commonly used. Not all cases of the condition require medication but all will need special management.

Extra attention to their feet, teeth, worm burden and any wounds is needed due to their reduced immune response and clipping out their long hair when needed will help with their comfort. Generally, 
the prognosis is good for 
animals with PPID if they are 
managed properly. More information and a voucher 
for a free test is available on but if you suspect your horse may be affected, speak to your own vet first for advice.