Cushing’s disease is a hormonal disease that affects the pituitary gland located at the base of the brain. It can cause hypertrophy (excessive growth), hyperplasia (abnormal multiplication of cells) and adenoma (benign tumour) formation, which results in an increased secretion of certain peptides and hormones particularly ACTH which leads to increased cortisol production. The peptides play a part in controlling a wide range of body functions and the hormonal imbalances cause a wide range of clinical signs. You also get a decrease in dopamine which helps control the size of the pituitary gland. Cushing’s disease is a very common, naturally occurring, progressive condition in more than 10% of horses over 15 years of age. In aged horses, there percentage is higher and results in a range of clinical signs that can be life threatening.
Symptoms and signs of Cushing’s disease
- The most common sign seen is abnormal hair growth and shedding. The horse looks like a “woolly bear.” They have a heavy curly coat (hirsutism) which doesn’t shed in summer; hence they sweat a lot and develop underlying skin infections.
- Sudden onset of polydipsia (drink excessively- average horse drinks 30-50 litres/day depending on exercise and climatic conditions)
- Often excessive urination
- Chronic laminitis or recurrent attacks of laminitis. This can be one of the most devastating symptoms.
- Swayback appearance, pot belly, weight loss with an accumulation of fat, especially on the crest and top of rump, loss of muscle over topline.
- Compressed immune system which can lead to respiratory disease, skin infections, teeth problems, dental infections, foot abscesses and liver disease.
- Fat deposition above the eyes can make the eyes appear bulgy
- Horses with Equine metabolic syndrome (EMS or insulin resistance) may overlap with PPID cases
- Advanced cases, due to size of pituitary gland, can cause lethargy and neurological signs, as the brain become compressed. The horse gives the appearance of having a headache.
- Call your veterinarian for a correct diagnosis. Early recognition of the disease can help to control a lot of the symptoms.
- There are drugs available that will assist in managing the condition, which include Pergolide, Bromocryptine and other herbal remedies. Your vet will determine the best treatment.
- Book your farrier to trim horse regularly ever 4 to 5 weeks. It is essential to keep feet in good condition and control any pedal bone rotation.
- Body clip horse in warm weather to assist in temperature control. When horse is clipped rug accordingly, based on current climate.
- Undertake regular grooming or shampooing to contain skin conditions which can manifest under thick woolly coats.
- Feed a diet low in sugar and starch
- Addition of antioxidants like vitamin C and E
- Minimise stress to keep cortisol levels even
- 6 monthly dental check up to check teeth.