May 23, 2024

Cushing in horses: causes, symptoms, diagnosis and tips for optimal care

Equine Cushing's syndrome (ECS) is a widespread but often underestimated disease in horses that primarily affects older animals. It leads to an overproduction of the hormone cortisol, which can result in a variety of health problems. In this comprehensive article, you will learn everything you need to know about Cushing's in horses, from the causes and symptoms to the diagnosis and practical tips for the care and management of your sick horse.

What is Equine Cushing's Syndrome?

Equine Cushing's syndrome in horses, also known as pituitary pars intermedia dysfunction (PPID), is a chronic disease of the pituitary gland in horses. This gland is responsible for regulating numerous hormones that control essential body functions. Cushing's syndrome causes a degeneration of the dopaminergic neurons in the diencephalon, resulting in an uncontrolled release of hormones. The hormone ACTH (adrenocorticotropic hormone), which stimulates the adrenal glands to produce cortisol, is particularly affected.

Cortisol is a stress hormone that is essential for life in small amounts, but can be harmful to health in large quantities. An excess of cortisol can lead to a variety of problems, from metabolic disorders to an increased susceptibility to infections.

Causes of Equine Cushing's Syndrome in Horses

The exact causes of Cushing's syndrome are not yet fully understood. It is believed that a degeneration of neurons that produce dopamine plays a central role. Dopamine normally inhibits the release of ACTH. If this inhibition fails, the ACTH level rises uncontrollably, which in turn stimulates the adrenal glands to produce more cortisol.

Some factors that may contribute to the development of Cushing's include:

Age : The risk of developing Cushing's disease increases with the age of the horse. Horses aged 15 years and over are particularly at risk.
Genetics : There is some evidence that genetic factors may play a role. Some horse breeds appear to be more susceptible to Cushing's disease than others.
Previous illnesses : Illnesses that affect the metabolism or the immune system can promote the development of Cushing.

Symptoms of Cushing in Horses

The symptoms of equine Cushing's syndrome are varied and can begin gradually. Because the disease is chronic, symptoms often increase over time and can significantly affect the horse's quality of life. Here are the most common signs to look out for:

Long, curly coat (hirsutism) : A classic symptom of Cushing's is a coat that either doesn't shed at all or only sheds incompletely. The coat remains long, often curly, and is not completely shed even in summer.
Muscle atrophy and potbelly : Horses with Cushing's disease often show significant muscle atrophy, particularly in the back and croup. This leads to a characteristic potbelly.
Chronic laminitis : Another serious symptom is laminitis, an inflammation of the hoof capsule that can recur and is difficult to treat.
Increased drinking and urination (polydipsia and polyuria) : Increased drinking and increased urination are common signs of Cushing's.
Weakness and reduced performance : Affected horses often appear lethargic and lose energy and stamina.
Increased susceptibility to infections : The immune system of a Cushing horse is weakened, resulting in increased susceptibility to infections, especially skin infections.
Weight loss despite good appetite : Despite a normal or even increased appetite, weight loss can occur.
Irritability and behavioral changes : Some horses exhibit behavioral changes, such as increased irritability or apathy.

The importance of early detection

Early detection of Cushing's is crucial to slow the progression of the disease and improve your horse's quality of life. Since the symptoms often appear gradually and are initially non-specific, Cushing's is often diagnosed late.

Especially with older horses, you should regularly look for signs of the disease and do not hesitate to consult your veterinarian if you suspect it. An early diagnosis enables targeted therapy that can significantly improve your horse's life.

Diagnosis of Equine Cushing's Syndrome

Cushing's syndrome is usually diagnosed through a combination of clinical examination and specific blood tests. In particular, the ACTH level in the blood is measured, which is elevated in Cushing horses.

Common diagnostic methods include:

ACTH blood test : The ACTH level is measured in the blood. An elevated ACTH level indicates Cushing's syndrome.
Dexamethasone suppression test : In this test, the horse is given dexamethasone, a synthetic corticosteroid. In healthy horses, this leads to a decrease in blood cortisol levels, but this effect is absent in horses with Cushing's disease.
TRH Stimulation Test : This test measures the response of the pituitary gland to the administration of TRH (thyrotropin-releasing hormone). In horses with Cushing's, the response to TRH is increased, resulting in an increase in ACTH levels.

The choice of test depends on several factors, including the availability of the tests and the individual symptoms of the horse with Cushing's. It is important that the diagnosis is made by an experienced veterinarian to ensure accurate assessment and appropriate treatment.

treatment of Cushing's syndrome

A complete cure for Cushing's syndrome is not yet possible, but the symptoms can be significantly alleviated and the progression of the disease slowed down through targeted therapy. Treatment is usually carried out through a combination of drug therapy, adapted feeding and management measures.

Drug therapy : The most commonly used drug to treat Cushing's is pergolide, a dopamine agonist that inhibits ACTH production. Pergolide can effectively relieve symptoms and improve the horse's quality of life. The dosage must be individually adjusted and requires regular veterinary checks.
Adapted feeding : Since horses with Cushing's syndrome often suffer from insulin resistance, a low-carbohydrate diet is important. Avoid feeds that are high in sugar and starch and instead rely on roughage such as hay and feeds specially developed for Cushing horses.
Regular exercise : Exercise helps slow muscle loss and promote the horse's overall health. However, adapt the exercise program to your horse's health condition to avoid overtraining.
Hoof care : Since Cushing horses are at increased risk for laminitis, careful and regular hoof care is essential. Have your horse's hooves checked and cared for regularly by an experienced farrier.
Regular veterinary check-ups : Monitoring your horse's medication and health development through regular veterinary examinations is crucial to ensure the success of therapy and to make any necessary adjustments.

Adapted feeding for Cushing horses

Feeding plays a central role in the management of horses with Cushing's disease. Since these horses often suffer from insulin resistance, a diet that keeps blood sugar levels stable and minimizes the risk of laminitis is required.

Roughage : Hay should form the basis of the diet. Make sure to feed good quality hay that is low in sugar and starch. In some cases it may be useful to water the hay to further reduce the sugar content.
Concentrated feed : If concentrated feed is necessary, choose a feed specifically formulated for Cushing horses that is low in starch and sugar. Many feed manufacturers offer such products.
Oils and fatty acids : To provide energy, feed oils or high-fat additives such as linseed oil can be used. These provide energy without having a major impact on blood sugar levels.
Vitamins and minerals : Since Cushing horses often suffer from reduced nutrient absorption, it is advisable to give them a high-quality mineral supplement. Make sure that the supplement contains the necessary vitamins and trace elements in sufficient quantities.
Treats and snacks : Avoid sugary treats and snacks. If you want to make your horse happy, unsweetened carrot pieces or specially developed Cushing-friendly treats are suitable.

The Role of Exercise and Training

Regular exercise is essential for the well-being of a Cushing horse. Exercise helps to slow muscle loss, promote blood circulation and support metabolism. However, training must be adapted to the horse's state of health to avoid overexertion.

Light exercise : Start with light exercise, such as walks or easy trots that do not cause overexertion.
Targeted muscle building : Exercises that promote muscle building are particularly important. These include floor work, gymnastic exercises and targeted stretching exercises.
Regular breaks : Make sure to give your horse regular breaks, especially in hot temperatures or after intensive sessions.
Adaptation to the state of health : Observe your horse closely and adapt the training program if there are signs of fatigue, overexertion or health problems. Work closely with your veterinarian to develop the optimal exercise program for your horse.

hoof care and laminitis prevention

Cushing horses are particularly susceptible to laminitis, a painful and often serious disease of the hoof capsule. Proper hoof care and preventative measures are therefore essential.

Regular hoof care : Have your horse's hooves checked and trimmed regularly by an experienced farrier. Good hoof care can help minimize the risk of laminitis.
Adapted horseshoes : In some cases, special horseshoes can be useful to reduce the strain on the hooves and support the healing process in existing laminitis.
Monitoring diet : A low-carbohydrate diet is an important component in reducing the risk of laminitis. Avoid feeds that are high in sugar and starch.
Keep an eye on body weight : A healthy body weight is crucial to minimize stress on the hooves. Being overweight significantly increases the risk of laminitis.

Dealing with behavioral changes and psychological stress

Cushing's syndrome can have not only physical but also psychological effects on your horse. Many affected horses show behavioral changes such as increased irritability, apathy or even depressive symptoms. It is important to recognize these changes and respond to them appropriately.

Patience and understanding : Your horse may become more easily irritated or show unexpected reactions. Be patient and sensitive to these changes.
Maintain a routine : Horses are creatures of habit and a set routine can provide them with security and stability. Try to make the daily routine as predictable as possible.
Avoid stress : Reduce stress factors in your horse's environment by avoiding loud noises, frequent changes of location or excessive demands.
Working with your veterinarian : If your horse exhibits behavioral changes that do not improve with management measures, consult your veterinarian. In some cases, medication adjustments or additional therapeutic measures may be necessary.

Tips for the long-term care of a Cushing horse

Caring for a horse with Cushing's disease requires long-term commitment and comprehensive care. However, with the right measures, you can significantly improve your horse's quality of life.

Long-term planning : Cushing's disease in horses is a chronic disease that requires lifelong attention. Create a long-term care plan that includes regular medication, feeding, exercise, and veterinary checkups.
Training and information : Keep yourself regularly informed about new findings and treatment options. Exchanging ideas with other horse owners and experts can also provide valuable tips and support.
Dealing with setbacks : Even if you take the best care of your horse, setbacks can occur. Be prepared and react flexibly to changes in your horse's health.
Emotional support : Caring for a chronically ill horse can be emotionally stressful. Seek support from friends, online forums, or support groups for horse owners.

Living with a Cushing Horse: A Personal Account

Many horse owners initially face a great challenge when they receive a diagnosis of Cushing's disease. However, with the right attitude and the right measures, it is possible for your horse to lead a fulfilling and happy life despite this disease.

One example is Bella, a 20-year-old mare who was diagnosed with Cushing's syndrome five years ago. There was great concern at first, but with appropriate feeding, regular exercise and medication, Bella's condition has stabilized. Today she still enjoys long rides and is full of zest for life despite her illness.

Conclusion on Equine Cushing's Syndrome in Horses

Equine Cushing's syndrome is a serious disease in horses, but it can be managed with the right diagnosis and treatment. It is important that you recognize the symptoms in your horse early, consult an experienced veterinarian, and adapt the care and management of your horse to its special needs.

With patience, knowledge and the right support, you can give your horse a long and fulfilling life, despite the challenges that Cushing's syndrome brings. Make sure to provide a balanced diet, regular exercise and veterinary check-ups to ensure the best possible quality of life for your horse.