Cells responsible for the production of the neurotransmitter dopamine die faster in Cushing's horses. This malfunction triggers a negative sequence of hormonal events in the brain.
As the cells die, less dopamine is produced, causing the activity of the pituitary gland to get out of control. This dopamine deficiency leads to a massive enlargement of the pituitary gland, which in some cases can be the trigger for the development of tumours.
When the unchecked hormone ACTH reaches the adrenal cortex, it stimulates the production of the stress hormone cortisol. The horse shows increased blood sugar levels and its defences are weakened. Prolonged administration of cortisone can also be a trigger for Cushing's.
Cushing's is a typical age-related disease and therefore occurs more frequently in horses over the age of 15 (20% of horses aged 15+). The prevalence of the disease increases with age, with up to 95% of horses around the age of 30 being affected by Cushing's disease.
The disease generally begins very gradually, and it can take years before the typical symptoms appear. In the early stages of the disease, Cushing's manifests itself through apathy, heavy sweating and the horse tiring quickly.
The surest and most obvious sign is the disturbance of the coat metabolism, which results in unnaturally thick and long coats even in the summer months. As horses affected by Cushing's often have a malfunction of their sugar metabolism, they can be prone to hoof ulcers due to a resulting insulin resistance. Other symptoms may include infertility and the accumulation of fat deposits on the horse's body.
In the advanced stage, the following conditions may occur:
The incurable Equine Cushing's Syndrome can be diagnosed very reliably by means of an ACTH test. If the result is positive, treatment should begin immediately, as early detection and treatment are associated with good chances of success.
Despite the fact that Cushing's is an incurable disease, the horse's quality of life can be maintained or restored through targeted medication. The active substance Prascend, which must be administered to the horse daily for the rest of its life, is particularly successful in the treatment of Cushing's disease. Prascend stimulates the production of dopamine, which makes the pituitary gland stop the excessive production of hormones.
In order to maintain the horse's quality of life, it is recommended that the horse be seen regularly by the veterinarian, as in most cases the dose of the medication administered will need to be adjusted over time.
Monk's pepper can be given to the horse as a dietary supplement
In order to minimise the onset of Cushing's disease, it is advisable to keep the horse in a species-appropriate manner with plenty of room to move. Regular exercise is very important for preventing excess weight and stress, two factors that also contribute to the onset of Cushing's disease.