When a senior horse is diagnosed with Pituitary Pars Intermedia Dysfunction (PPID) — more commonly known as Cushing’s syndrome — it can be worrying for owners. Rest assured, by making informed decisions and adapting their management, they can still thrive.

Over 20% of horses aged above 15 years (and 25% of those over the age of 20) may have PPID, and it can affect all breeds. Although it may seem more common in ponies, this may just be because they tend to have longer lifespans.

What is PPID?

PPID is an endocrine (hormonal) disorder affecting the pituitary gland, a small organ found at the base of the brain which regulates, produces and stores hormones.

In short, horses with PPID over produce some hormones, including adrenocorticotropic hormone (ACTH).  How this increase in hormones leads to the clinical signs of PPID is still not fully understood, but it’s clear PPID can have a significant impact on a horse’s overall health and appearance.

Clinical signs of PPID

Severity of signs will vary between individuals, and some equines may only show mild signs of Cushing’s.

Common clinical signs of PPID are listed below:

  • Excessive coat growth (Hypertrichosis)
  • Coats being slow (or failing) to shed
  • Muscle wastage
  • Weight loss
  • Excessive sweating
  • Increased drinking and urination
  • Lethargy and poor performance
  • Behavioural changes
  • Pot-bellied appearance
  • Abnormal fat distribution
  • Delayed wound healing and increased infections
  • Increased susceptibility to parasites

Diagnosing PPID

Diagnosing PPID involves a veterinary examination of the clinical signs. A blood test will be carried out to measure the concentration of ACTH in the horse’s blood — elevated levels indicate PPID.

Test results maybe ambiguous, and your vet may suggest a more refined thyrotropin-releasing hormone (TRH) stimulation test to confirm diagnosis.

Managing a senior horse with PPID

Equines suffering with PPID may be under or overweight, retired with multiple age-related issues, or active in good condition.

The following are key strategies for managing a horse’s symptoms and will help them to stay as healthy as possible.

Regular vet checks

Regular blood tests (for ACTH and insulin status) help track any progression of Cushing’s, allowing you to make necessary adjustments to your horse’s management.

Body condition, muscle tone, and dental health should also be assessed regularly.

Maintain a healthy weight

Carefully monitoring body condition is essential. Use a body condition scoring system to help you assess your horse’s condition objectively — just casting an eye over your horse isn’t accurate.

However, some horses and ponies may have large regional fat deposits, such as a cresty neck or fat pads over the loins, despite being thin overall. In these situations, body condition scoring systems need to be used with care.

Regular weigh taping is a helpful tracker.

Managing the laminitis risk

If horses or ponies are also insulin dysregulated, they’re at increased risk of developing laminitis. Maintaining a healthy body condition and limiting total starch and sugar intake are priorities.

Exercise helps maintain muscle tone and may improve insulin sensitivity, which could help to reduce the laminitis risk. Tailor the intensity of exercise to the horse’s capability — even light activity may be helpful.

Feeding forage

Ideally, forage should be the cornerstone of all horse’s diets. It helps healthy digestive function, encourages chewing and provides the bulk of calories (energy).

If possible, provide unlimited access to forage. Book regular dental checks, as even mild teeth discomfort can prevent a horse from eating enough forage to maintain a healthy weight.

Forage quality

Soaking hay helps reduce its water-soluble carbohydrate (WSC) or ‘sugar’ content. Results are variable, so best practise is to have your hay analysed (for WSC using the wet chemistry method) to assess its suitability.

Forage replacers maybe required for those with severe insulin dysregulation or dental issues.

Managing grass

Restrict sugar intake by limiting access to grazing. Grazing muzzles, strip grazing and track systems may be useful.

Avoid turning out on sunny frosty mornings or during grass flushes. Higher risk horses and ponies may even require grass-free turnout.

Bucket feeds

Forage alone doesn’t guarantee a fully balanced diet, especially once soaked. Bucket feeds should provide essential nutrients, without high levels of starch and sugar.

Bear in the mind the following:

  • Feed balancers are ideal for horses who maintain weight on forage alone, providing essential vitamins and minerals and protein, without excess calories.
  • Fibre-based feeds, low in starch and sugar, are appropriate for PPID horses where more calories are required. Higher oil feeds can be used for underweight horses.
  • Consider feeding more small meals throughout the day.
  • If unsure, contact a nutritional advisor who can ensure your PPID horse’s diet provides everything they need.

Monitor their temperature

Senior horses may have difficulty regulating their body temperature and this may be exacerbated in those with PPID, so you will need to change/remove their rugs more often.

Thick coats could need clipping all year round. Those prone to heavy sweating may also require extra electrolytes in their diet, while vitamin C supplementation may benefit those prone to respiratory infections.

Looking to the future

Plenty of senior PPID horses continue to live fun active lives. By adapting their management, diet and exercise, and staying vigilant, you can help your horse continue to thrive whether ridden or retired, despite the challenges they face.

Compassionate care, combined with scientific understanding, is the key to supporting your horse.

If you would like tailored advice for your horse or pony, please contact the SPILLERS Care-Line here. For further advice and information about how best to care for your super senior horse and to join the SPILLERS Super Seniors Club click here.

Main image of Sandy, a senior horse with PPID. © Spillers

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