The equine TRH stimulation test is a diagnostic procedure we use to assess the function of the pituitary gland in horses suspected of having Equine Cushing's Disease (also known as Pituitary Pars Intermedia Dysfunction or PPID). PPID is a common endocrine disorder in older horses that results from dysfunction of the pituitary gland, leading to excessive production of certain hormones, particularly adrenocorticotropic hormone (ACTH). See our previous post for Part I. 

Here's how the equine TRH stimulation test works:

1. **Preparation**: Before conducting the test, the horse is typically fasted from grain for a period of time to ensure accurate blood sampling and minimize the influence of recent feed intake on hormone levels. Access to hay and forage is allowed.

2. **Administration of TRH**: TRH, or thyrotropin-releasing hormone, is a hormone produced by the hypothalamus, a region of the brain that regulates various physiological processes, including hormone secretion by the pituitary gland. In the TRH stimulation test, a veterinarian administers a specific dose of synthetic TRH intravenously or intramuscularly to the horse.

3. **Blood Sampling**: Just prior to and following the administration of TRH, blood samples are collected from the horse at specific time intervals, typically at baseline (before TRH administration) and at designated time points after TRH administration, such as 10, 20, and 30 minutes.

4. **Measurement of Hormone Levels**: The blood samples collected during the test are analyzed to measure the concentration ACTH. ACTH is the hormone primarily associated with PPID, and its levels are often elevated in affected horses due to dysfunction of the pituitary gland.

5. **Interpretation of Results**: The equine TRH stimulation test helps veterinarians assess the pituitary gland's response to TRH stimulation. In horses with PPID, the pituitary gland may exhibit an exaggerated or prolonged release of ACTH in response to TRH administration compared to healthy horses. Elevated ACTH levels following TRH stimulation are indicative of pituitary dysfunction and support a diagnosis of PPID.

It's important to note that the equine TRH stimulation test is just one of several diagnostic tools used to evaluate horses suspected of having PPID. Veterinarians may also consider clinical signs, such as abnormal hair growth, excessive drinking and urination, lethargy, and laminitis when making a diagnosis of PPID and determining the appropriate treatment and management plan for affected horses.

Overall, the equine TRH stimulation test plays a valuable role in diagnosing PPID and guiding treatment decisions, helping veterinarians provide optimal care for horses affected by this common endocrine disorder. This test allows us to catch horse's in the early stages of Equine Cushing's Disease so that we can prevent the significant health problems caused by this disease. 

Equine Cushing's Disease, also known as Pituitary Pars Intermedia Dysfunction (PPID), is a common endocrine disorder that affects horses, ponies, and occasionally donkeys. While it primarily impacts older equines, it's essential for all horse owners and caregivers to understand its causes, symptoms, diagnosis, and management. In this comprehensive guide, we'll delve into the intricacies of Equine Cushing's Disease and explore how to best support horses affected by this condition.

Understanding Equine Cushing's Disease: Equine Cushing's Disease is characterized by the dysfunction of the pituitary gland, which leads to an imbalance in hormone production, particularly an overproduction of cortisol. The pituitary gland, located at the base of the brain, regulates various bodily functions, including metabolism, immune response, and stress management. When it malfunctions, as in the case of Cushing's Disease, it can have far-reaching effects on the horse's health and wellbeing.

The exact cause of Equine Cushing's Disease remains unclear, but it is believed to involve changes in the regulation of the hypothalamic-pituitary-adrenal (HPA) axis. Factors such as age, genetic predisposition, and environmental influences may contribute to its development. Additionally, research suggests that certain breeds, such as ponies and Morgans, may be more susceptible to the condition.

Symptoms: Recognizing the symptoms of Equine Cushing's Disease is crucial for early detection and intervention. Common signs include:

1. Abnormal hair growth, such as a long, curly coat that fails to shed.
2. Excessive sweating, particularly in areas where the hair is thick.
3. Increased thirst and urination.
4. Muscle wasting and loss of topline.
5. Fatigue and lethargy.
6. Pot-bellied appearance.
7. Recurrent infections, including hoof abscesses and respiratory issues.
8. Laminitis: This is the most devastating effect of Equine Cushing's Disease. Laminitis is due to the toxic effect of the persistent elevated ACTH levels on the lamina of the horse's foot

Diagnosis: Diagnosing Equine Cushing's Disease typically involves a combination of clinical signs and blood tests. We will perform tests to measure adrenocorticotropic hormone (ACTH) levels, which are often elevated in affected horses. The TRH Stimulation test (see our next post: Equine Cushing's Disease Part II) is a much more specific test and allow us to diagnose horses with early and sometime subclinical Cushing's disease

Management: While there is no cure for Equine Cushing's Disease, effective management strategies can help control symptoms and improve the horse's quality of life. Treatment options may include:

1. Medications: The most important part of management is the use of Prascend (Pergolide). Prascend is a dopamine agonists helps to regulate hormone levels and improve clinical signs.
2. Dietary modifications: A balanced diet low in sugars and carbohydrates can help prevent weight gain and insulin resistance, which are common complications of Cushing's Disease.
3. Regular exercise can help maintain muscle tone and overall health.
4. Routine veterinary care: Regular monitoring of ACTH levels and clinical signs is essential for adjusting Prascend dose. We recommend testing ACTH levels once year. 

Conclusion: Equine Cushing's Disease poses significant challenges for both horses and their caregivers, but with early detection and proactive management, affected animals can lead fulfilling lives. By understanding the causes, symptoms, diagnosis, and treatment options associated with this condition, horse owners can provide the best possible care for their equine companions. Collaboration between veterinarians, caregivers, and equine specialists is key to managing Equine Cushing's Disease effectively and promoting the health and wellbeing of affected animals.

Learn about vaccines and wellness exams and why both are important for your horse.

Pasture Management for Springtime Grass

After months of barren ground or snow covered fields, we are slowly starting to see the gorgeous signs of spring in New England once again. The horses are shedding and eagerly awaiting any chance they have to nibble some delicious green grass. Below we provide very helpful guidelines for the slow controlled introduction to keep our horses safe and healthy.

Horses that always live outside have the benefit of mother nature's slow introduction to grass as it grows through the first weeks of spring. Horses living in stalls with only partial day turnout have to be more strictly controlled in their introduction to pasture to prevent the serious trouble that can occur with too much fresh grass too quickly. Over indulgence in grass can result in gas colic and laminitis. So what can you do to protect your horse from the potential hazards of too much grass too quickly?

Here are guidelines to assist you in coming up with a pasture introduction plan:

Horses on 2-12 hours a day of pasture:

If you have limited pasture but still want your horse to reap the benefits of daily turnout you probably fall into this category. Most horses in a boarding situation with access to grass will be in this group. Take care to closely follow a pre-determined time scale of introduction for these horses. Begin with 20 min of grazing a day, adding 20 min every 2-4 days until the horses is up to his regular daily turnout time. You can also use a grazing muzzle (see below) if you need to introduce pasture more rapidly. With a grazing muzzle you can add 20 min per day of turnout until on full turnout. Once on full turn out keep muzzle on for about a week then alternate every other day for a week then it should be safe to remove the grazing muzzle.

Horses living out 24/7, a field big enough for constant grazing all season:

These horses normally do fine by themselves. Nature gives its own slow introduction to new grass and horses graze as the grass grows and adapt on a day- to- day basis. These situations are far more common in geographical areas like in the western US where grazing lands are plentiful. If your grass begins to come up very quickly you may want to use a grazing muzzle for a week or two to slow your horse's grass consumption during this period of rapid grass growth.

The most important thing to remember is that grass is a great source of calories for your horse. For the hard keeper thoroughbred-type, this is a great way to bulk them up after a long winter. For the rest of us with hearty warmbloods or chubby ponies, we have to watch these horses very carefully. In addition to the introduction guidelines above, we recommend the easy keepers or over conditioned horses use a grazing muzzle to slow their intake of grass and thus calories. While you may think this is cruel you are really doing your horse a huge favor. They can still eat grass normally it simply reduces the amount of grass they eat in a given time. If your horse has EMS (Equine Metabolic Syndrome) or PPID (Cushing's) please consult NBEA Veterinarians to come up with a safe plan catered to your horse.

First update of 2024

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Suspensory ligament injuries are one of the most common soft tissue injuries we see in the sport horse. These injuries can be very frustrating. A recent study from Virginia Equine Imaging shows that Shockwave treatment can return these horses to their previous level of work faster than only rest and with similar results to surgery. North Bridge Equine often uses shockwave as our first line treatment for proximal suspensory disease and we have seen very good results with this treatment.

Click the link below to read more about the study:

http://www.thehorse.com/articles/37077/treating-psd-in-sport-horses-surgery-shock-wave-or-both#st_refDomain=www.facebook.com&st_refQuery=/