Building topline muscle and dealing with topline loss is a common struggle for horse owners.

Your horse may have a weak topline due to a variety of factors including nutrition and exercise. Physiological factors such as age or underlying health conditions can also affect topline muscle.

With the right feeding plan, exercise program, and lifestyle, you can help your horse build muscle mass and strength. Topline muscles are not only appealing to look at, but they also enhance mobility and improve overall fitness and longevity.

Topline loss often coincides with other issues that need to be properly managed. Careful examination of the horse’s daily routine and health background can help identify the underlying cause of muscle loss.

Horses with metabolic disorders such as PSSM or Cushing’s require specific approaches for supporting muscle development. Horses with gut issues and senior horses may also require special care.

We can help you develop a nutrition and management program that supports the development of healthy muscle. You can submit your horse’s diet for a free analysis by our equine nutritionists and they can give you personalized suggestions for building a better topline.

What are Topline Muscles?

The topline muscles in the horse run along the vertebral column and include the withers, back, loin and croup.

The major muscles in these areas are the Latissimus Dorsi, Longissimus Dorsi and Trapezius muscles.

In a healthy horse, the topline muscles will feel smooth and flat, and the body should appear well-rounded without excessive fat deposition.

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Signs and Causes of Poor Topline

You can assess your horse’s topline condition by looking at the withers, back, loin and croup areas one at a time. If any of these areas appear sunken-in or concave, that means that there is a lack of muscle.

Overweight horses may appear to have ideal topline muscling on first observation, but subcutaneous fat will be covering the muscles.

Feeling the areas to distinguish between fat and lean tissue is helpful for accurate body condition scoring. Muscle will feel firm, whereas fat will feel spongy.

A lack of topline muscling in your horse can be attributed to many different factors, such as:

  • Poor nutrition or lack of dietary protein
  • Atrophy associated with reduced exercise or muscle engagement
  • Old age
  • Lameness
  • Incorrect saddle fit
  • Musculoskeletal issues such as polysaccharide storage myopathy (PSSM)
  • Endocrine diseases such as Cushing’s disease or pituitary pars intermedia dysfunction (PPID)
  • Overriding dorsal spinous processes (or kissing spines)
  • Gastric ulcers or other digestive issues

If your horse is losing muscle or has struggled to attain adequate topline, these factors should be carefully evaluated by a qualified equine professional including your nutritionist or veterinarian.

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How to Build Topline in your Horse

Step 1) Identify underlying conditions

Certain equine diseases like Cushing’s / PPID and PSSM can accelerate topline muscle loss. Proper diagnosis and management of these conditions with the right nutrition and exercise programs is imperative to minimize further muscle wasting.

PPID – Cushing’s Disease

The progression of Pituitary pars intermedia dysfunction (PPID) directly affects protein metabolism, which results in muscle atrophy in most affected horses. [11] Depending on their body condition and the presence of insulin dysregulation, horses with PPID require specialized diets catered to their individual needs.

All horses that develop PPID are at higher risk of insulin resistance and laminitis. Even if it is unclear whether your horse has IR, it is recommended to manage them as if they are insulin resistant. [13]

Horses with PPID that have a history of IR or laminitis require a diet very low in soluble carbohydrates, high in good quality protein and balanced vitamins and minerals. [14]

PSSM – Equine polysaccharide storage myopathy

PSSM is a metabolic disorder that stems from abnormalities in carbohydrate metabolism. [9] Two of the most common symptoms are muscle wasting along the topline and an abnormal hindlimb gait. [6]

For horses diagnosed with EPSM, it is recommended to feed a diet very low in sugar and starch (less than 12% total NSC, dry matter basis), high in fat and balanced in protein, vitamins and minerals. [10]

Regular, consistent exercise is also strongly encouraged to control symptoms in these horses.

Kissing Spines – Overriding Dorsal Spinous Processes

Kissing spines in a condition in which the dorsal spinous processes (DSPs) of the thoracic and/or lumbar vertebrae touch or “kiss”. [16] The DSPs can override at only one or two spots, or it can encompass several locations along the back.

Horses with kissing spines can experience back pain – they’re “cold-backed” and sensitive to palpation over the thoracic spine. [16] This discomfort stems from bone-on-bone contact and bony remodeling where the DSPs touch.

Affected horses may exhibit a weak or poorly developed topline because they’re resistant to using these muscle groups because of discomfort.

Step 2) Energy and protein needs

Horses that have poor topline sometimes require additional protein in their diet. For muscle growth to occur, your horse’s diet needs to provide sufficient energy and protein.

Good quality forage should be the basis of the diet and hay should be selected based on the horse’s work level and individual needs.

Depending on the energy and protein content of your horse’s forage, supplemental energy and/or protein sources may need to be added to meet your horse’s daily requirements.

Amino Acids

Amino acids are the building blocks of protein and can be found at varying levels in different feedstuffs. There are 10 essential amino acids that must be provided in your horse’s diet because they cannot be synthesized in the body.

The total amount of dietary amino acids isn’t the only thing that matters; the proper balance of amino acids matters too. Providing a complete profile these essential amino acids will support muscle repair and recovery following exercise.

Lysine, methionine and threonine are widely considered to be the three most limiting essential amino acids in the equine diet. This means they are the most likely to be deficient in the diet. If one of these amino acids is insufficient in the diet, protein synthesis can be compromised. [5]

Protein Sources

When supplementing with protein, it is important to choose good quality, highly digestible protein sources that contain these essential amino acids in the correct balance.

Some of the best high-quality protein sources to feed your horse include:

  • Soybean meal
  • Canola meal
  • Hempseed meal
  • Flaxseed meal
  • Whey protein concentrate

Of these, soybean meal and canola meal have the highest lysine content and are a great choice if an amino acid deficiency is suspected.

Alternatively, supplemental amino acids can be used to specifically boost the lysine, methionine, and threonine content of the diet.

This option may be recommended for horses that generally get enough protein in their diet but require targeted supplementation to correct for an imbalance in amino acids.

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  • Optimal protein synthesis
  • Hoof & coat quality
  • Topline development
  • Athletic performance

Step 3) Vitamin and Mineral Needs

Vitamins and minerals are crucial for supporting metabolic processes that breakdown nutrients and make proteins. Muscle growth can only occur if there are sufficient levels of vitamins and minerals in the diet.

Deficiencies in certain vitamins and minerals can lead to impaired muscle function and poor recovery from exercise. [10] This can hinder muscle repair and development of topline muscles.

Some of the most important nutrients for exercise recovery and their requirements for mature horses include:

  • Magnesium: 15 to 20 grams per day
  • Vitamin E: 1000 IU per day
  • Selenium: at least 1.25 mg per day, ideally 2-3 mg per day

Feeding a balanced vitamin and mineral supplement or complete feed at the recommended feeding rate will ensure that your horse’s vitamin and mineral requirements are met.

Antioxidants like vitamin E and selenium protect muscle cells from oxidative damage that occurs during exercise. Depending on the level of work your horse is engaged in, extra supplementation of vitamin E and selenium can be beneficial.

Step 4) Support Digestive Health

Loss of topline muscle is a common issue for older horses, particularly after 20 years of age. This can often be linked to reduced feed efficiency; senior horses are less able to extract nutrients from foods they consume.

Lower feed efficiency may be the result of impaired digestive health due to decreased diversity of the bacteria in the gut microbiome. [13]

Feeding a balanced, forage-first diet contributes to optimal hindgut health. Supplementation with yeast also appears to improve feed efficiency and nutrient absorption.

Your senior horse may benefit from the addition of a gut health supplement to promote hindgut health and immune function. Make sure any digestive health supplement you select provides sufficient levels of probiotics, digestive enzymes and prebiotics.

Another reason for weak topline can be poor foregut digestion due to gastric ulcers. Common treatments that buffer the stomach acid or prevent its production result in an artificially high pH in the stomach. However, the stomach has a low pH for a reason. This is to activate digestive enzymes and kill potentially harmful microbes.

If digestive enzymes are not activated in the stomach, nutrients such as protein and carbohydrates will be less easily broken down in the stomach and small intestine. Therefore, gastric ulcer treatments can have unintended consequences on the rest of the digestive tract and overall nutrient absorption, including decreased amino acid absorption and poor topline.

Step 5) Identify lameness

Lameness in horses can encompass a wide range of conditions but usually stems from pain in the lower limbs and back. Although low-grade lameness can be difficult to detect it can still result in poor performance and welfare concerns.

Many horse owners find it difficult to accurately identify lameness in their horse. [15] Failure to identify lameness early can result in worsening of the underlying issue.

Consulting with your veterinarian and using science-based ethograms can help to identify subtle or overt lameness through objective observation. [1]

Proper identification of problem areas will allow you to take the appropriate steps to improve your horse’s soundness with your team of equine professionals.

Feeding the right diet can also help to support joint and connective tissue health on a preventative basis.

Whether your horse is ridden for pleasure or competition, it is essential that lameness is identified and managed accordingly before subjecting the horse to the exercises needed to build topline muscle.

Step 6) Use properly fitting equipment

Choosing the right equipment for riding is important to ensure that your horse is comfortable and moving without pain.

A poorly fitting saddle can result in pain points, which can cause the horse to compensate in their movement. This compensatory movement can lead to muscle atrophy in the topline area. [7]

Saddle fit should be assessed by a qualified saddle fitter at the beginning of training and monitored as the horse’s topline changes. Horses with an underdeveloped topline typically require more frequent assessments compared to horses with more established muscling.

If you’re using bits and bridles, they should also be assessed for correct fit. It is important to check them regularly for damage to avoid pinch points, rubbing or poking. Discomfort with the bit and bridle can cause horses to change their gait which can affect topline muscle and lead to joint issues.

Step 7) Implement proper exercise

For muscle growth to occur, the muscles need to be stimulated with some form of resistance training. Ideally, resistance training should be done on a consistent basis to see the best results.

There is limited scientific evidence in horses available to assess which exercises are effective for building topline muscles. However, there are many different exercises that are anecdotally regarded as effective.

Below are some of the best purported topline-building exercises for horses: [11]

Long and low: Allow your horse to stretch their head down and work in a relaxed frame on a loose rein or at liberty.

Transitions: Whether lunging or riding, downward or upward transitions are excellent ways to work on building strength and balance along the back and hindquarters.

Backing up: Backing up encourages the horse to carry more of the horse and rider’s weight in the hind end and engages the back and hindquarters.

Hill work: Hand walking or riding up and down hills helps to strengthen the back and hindquarters.

Pole work: Using poles in lunging or riding is an engaging way to work the topline muscles. There are hundreds of different exercises available.

Horse “Sit-Ups”: Applying pressure on the midline of the horse’s abdomen encourages the horse to lift its back, engaging the abdominal muscles.

Step 8) Maintain a stretching routine

Guiding your horse through stretches before exercise can increase flexibility of the muscles and improve posture and balance, making workouts more productive. [4]

Some effective stretches to engage the topline muscles include: [8]

  • Chin to Chest
  • Chin Between the Knees
  • Chin Between the Fetlocks

Stretching should be done in a slow, relaxed manner. When done correctly and consistently, stretching before and after exercise can help reduce muscle fatigue and soreness.

Step 9) Maximize turnout time

Turnout has a multitude of benefits, not only for muscle development but for the mental health of your horse as well.

Despite the common belief that turnout can cause injury, more studies demonstrate that it can be done safely. Improved welfare is observed in horses that are turned out, even for 1 hour per day. [3]

Turnout in hilly paddocks with varied terrain and/or with other horses is a great way to increase your horse’s exercise level throughout the day. Utilizing a paddock paradise system can promote even more movement in your horse’s routine if you don’t have access to hilly or varied terrain.

Providing enrichment activities in your horse’s environment can also make turnout time more stimulating and encourage more movement which can activate topline muscles.


If you are concerned about recent topline loss, consult with your veterinarian to rule out any underlying medical conditions.

Feeding a diet that provides adequate energy, high-quality protein, and meet the horse’s vitamin and mineral requirements, can go a long way to supporting topline muscle growth.

Beyond that, adding some simple exercises can help stimulate the muscle to support protein synthesis and topline development as well as maintenance.

Struggling with topline issues? Submit your horse’s diet for a free evaluation to develop a balanced nutritional plan.

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  3. Lesimple, C. et al. Free movement: A key for welfare improvement in sport horses? Appl An Behav Sci. 2020.
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  11. Banse, H.E. et al. Markers of muscle atrophy and impact of treatment with pergolide in horses with pituitary pars intermedia dysfunction and muscle atrophy. Dom Anim Endo. 2021. View Summary
  12. Pitman, T. 8 Targeted Strengthening Exercises for Horses. Horse Canada. 2016.
  13. Jarvis, M. et al. Nutrition considerations for the aged horse. Equine Vet. Ed. 2017.
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  15. Rhodin, M. et al. Head and pelvic movement asymmetries at trot in riding horses in training and perceived as free from lameness by the owner. PLoS One. 2017. View Summary
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