Case Study: Topline Improvement in a Retired Show Jumper

In April 2024, a diet evaluation was requested for a 22-year-old retired show jumper gelding weighing approximately 1,200 lb (544 kg) in Quebec, Canada.

Reported health concerns included Pituitary Pars Intermedia Dysfunction (PPID), arthritis, and poor topline condition.

The horse owner’s primary goal was to support and maintain the horse’s topline development.

Presentation Prior to Diet Intervention

At the time of evaluation, the gelding had recent environmental changes alongside pre-existing medical conditions that needed to be considered.

In February 2024, he was moved to a new barn. The owner noted the transition went smoothly. She also said that she believed the new barn helped the horse gain weight at the beginning of the year due to better hay quality and more attentive management.

The gelding also presented with the following special care needs:

• Pituitary Pars Intermedia Dysfunction
• Poor topline muscling
• Hock arthritis

The gelding was listed as being at a normal weight in his submission, and the owner noted that his PPID (also known as Cushing’s disease) was well managed.

The following photo was provided of the gelding from February 2024, the day before his move to a new barn:

Feb 2024

Horse History

The gelding was turned out during the day and brought into a stall at night. He was provided free choice hay that was fed several times per day.

In addition, he was fed eight cups of SuperFibra Integri-T (Purina) spread over four meals throughout the day, and 20 grams Tri-Acta Equine (Integricare Animal Health) supplement.

The horse was being fed first cut grass hay, and a hay analysis indicated the following nutritional content:

The gelding was also listed as being in moderate exercise, working at a walk, trot, and canter on trails 2 – 4 times per week. The owner noted that he had good energy when ridden, despite the arthritis and topline muscling concerns.

Pituitary Pars Intermedia Dysfunction

Pituitary Pars Intermedia Dysfunction (PPID) is an endocrine disease that is common in older horses. ^[1] It is estimated that 20% of horses over the age of 20 and 30% of horses over the age of 30 are affected by PPID. ^[2]

This condition results from degeneration of dopamine neurons in the hypothalamus in the brain. This causes the hypothalamus to under-produce dopamine, a signalling molecule that communicates with the pituitary gland, a nearby region of the brain.

Without dopamine, the pituitary gland over-produces a hormone called adrenocorticotropic hormone (ACTH). Although the exact cause of neurodegeneration of the hypothalamus is not known, researchers theorize that increased oxidative stress in the hypothalamus may contribute. ^[3]

Oxidative stress is caused by unchecked or excessive production of free radicals that can damage lipids (fats), proteins, and DNA. Oxidative stress has been linked to a number of age-related diseases in humans, but is not as well studied in horses. ^[4]

PPID can result in symptoms such as decreased athletic performance, changes in attitude, delayed coat shedding, and muscle loss along the topline — all of which can negatively impact a horse’s quality of life. ^[5]

In addition, PPID is often accompanied by other health concerns such as insulin resistance, which increases the risk of laminitis. ^[6]

PPID is commonly managed with a combination of medication, such as Pergolide, and dietary adjustments.

Dietary interventions may include:

• Management of energy intake to maintain a good body condition
• Low carbohydrate diets for horses with PPID and concurrent insulin resistance
• Balanced vitamin and mineral intake
• Supportive supplements including Chasteberry

In this case, the gelding’s PPID was reported as well controlled, and no pressing symptoms were noted with the exception of topline muscle wasting.

Topline Health

Before dietary changes were made, the gelding was having issues with topline muscle maintenance that were likely due to a combination of PPID and age-related muscle atrophy.

PPID affects protein metabolism and commonly results in muscle atrophy in affected horses. While treatment with Pergolide may improve insulin sensitivity in horses with PPID, it may not address problems with muscle loss. ^[7]

Aging also contributes to changes in skeletal muscle metabolism that can lead to a loss of muscle mass over time. ^[8] Supporting muscle maintenance in aged horses with or without PPID requires a balanced diet and regular exercise.

In addition to energy and protein, horses rely on nutrients including vitamins and minerals to build and repair muscle tissue, provide antioxidant protection, and directly support muscle function.

Key nutrients for supporting muscle health include: ^{[9][10][11][12]}

• Zinc, copper, manganese, and selenium: critical cofactors in the function of antioxidant enzymes and other proteins found in muscle
• Vitamin E: an antioxidant
• Calcium and magnesium: play a direct role in muscle contraction

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Arthritis

Osteoarthritis, also called degenerative joint disease, is a type of arthritis that is common in horses. The prevalence of arthritis is estimated at greater than 50% in horses over the age of 15, and 80 – 90% in horses over the age of 30. ^[13]

Furthermore, exercise puts additional strain on joints, and arthritis may account for 60% of lameness issues in performance horses. ^[14] Retired performance horses are prone to arthritis-related problems that can compromise their quality of life.

Common symptoms of arthritis in horses include:

• Stiffness
• Pain
• Joint swelling
• Lameness
• Gait abnormalities

Arthritis is commonly managed with non-steroidal anti-inflammatories drugs (NSAIDs), joint injections, or other medical interventions such as platelet-rich plasma treatments.

A balanced diet is critical to support joint health in horses. Nutrients such as zinc, copper, manganese, selenium, vitamin E, and vitamin C are important for ensuring optimal function of enzymes that maintain connective tissue and providing antioxidant support to protect from oxidative stress. ^[15][16]

In addition, some nutritional supplements can benefit horses affected by joint concerns. The omega-3 fatty acids eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown to reduce inflammation in horses with arthritis. ^[17]

Supplements such as methylsulfonylmethane (MSM), a bioavailable form of sulfur, can also help to maintain healthy joint tissue. Sulfur is a trace mineral essential for the formation of cartilage and glucosamine found in joint tissue.

Initial Diet

At the time of the nutrition consultation, the horse’s daily ration consisted of:

• Free choice grass hay
• 8 cups per day of SuperFibra Integri-T
• 20 grams of Tri-Acta H.A. Equine joint supplement

Overall, the diet was deficient in several key nutrients, including:

• Sodium
• Zinc
• Manganese
• Selenium
• Vitamin E

However, the gelding was meeting his protein requirement and the the hydrolyzable carbohydrate (sugar and starch) content of the diet was properly controlled at 10.6% of dry matter.

Intervention

As part of the consultation, an improved diet plan was proposed to address the specific concerns of the horse.

Table 2. Summary of Diet Intervention

Complete feeds are a good source of energy, protein, vitamins, and minerals, but they need to be fed at the manufacturer’s recommended daily feeding rate to fulfill all of a horse’s vitamin and mineral requirements. Many owners feed a reduced rate of complete feed to avoid excess weight gain.

In situations like these, switching to a forage-based diet and/or adding a vitamin and mineral supplement can help to meet horses’ requirements without exceeding their energy and protein needs.

To balance the diet, Mad Barn’s AminoTrace+ was added as a concentrated source of vitamins and minerals. In addition to ensuring the horse’s vitamin and mineral needs are met, AminoTrace+ provides a rich source of antioxidants and amino acids to support horses with metabolic issues such as PPID.

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• Complete mineral balance
• Supports metabolic health
• Formulated for IR/Cushing's
• Hoof growth

Balancing the Diet

The primary focus of the dietary intervention was to improve the gelding’s topline health. While his diet already provided adequate energy and protein, it was essential to rebalance it to ensure sufficient vitamins and minerals for muscle and overall health.

Feeding AminoTrace+ helped meet the gelding’s vitamin and mineral requirements and addressed concerns related to nutritional deficiencies.

Updated Diet

After the consultation, the owner added AminoTrace+ and salt, but opted to omit W-3 oil and keep SuperFibra Integri-T.

The horse’s updated daily diet consisted of:

• Free choice hay
• 8 cups Purina SuperFibra Integri-T
• 2.25 scoops (225 grams) of AminoTrace+
• 2 tablespoons of plain loose salt
• 20 grams of Tri-Acta H.A. Equine joint supplement

After confirming that the owner opted to keep Integri-T in the diet, the AminoTrace+ feeding rate was adjusted to 1.5 scoops (150 grams) per day to more effectively balance the diet.

Outcome

Overall, the dietary adjustments led to a significant improvement in topline health. The owner noted that she began seeing improvements after approximately one month.

The following photos show differences in topline after three months on AminoTrace+:

Jul 2024

Jul 2024

Discussion

Many horses have difficulty maintaining their topline as they age, and PPID can present additional challenges. Given that the gelding in this case study was both aged and diagnosed with PPID, his difficulty maintaining topline is not surprising.

Since the horse was at a healthy weight and consuming an adequate amount of protein, maintaining his caloric intake while meeting vitamin and mineral requirements was a priority for the updated feeding program. Due to his metabolic issue, it was also important to provide additional supportive care.

The inclusion of AminoTrace+ and salt helped to meet this retired show jumper’s nutrient needs and support his metabolic health. Addressing nutritional deficiencies and continued regular exercise supported improved muscle development.

Unfortunately, in May, the gelding began exhibiting signs of a respiratory infection, including lethargy and coughing. Blood results indicated the presence of a respiratory infection.

In May, the gelding was treated with antibiotics, and in June clenbuterol was added due to persistent respiratory issues. The owner also added spirulina to the horse’s diet to provide additional respiratory support.

Spirulina is a powdered algae supplement rich in antioxidants, which help supporting the immune system and protecting cells in the body against inflammation.

The owner did not observe a significant impact from feeding spirulina on the horse’s respiratory symptoms. Consequently, in late June, the owner decided to switch to W-3 oil as a source of the omega-3 fatty acid DHA, which may support respiratory health in horses. ^[18]

This case is ongoing, and updates on the horse’s respiratory health in response to DHA supplementation will be added in the future.