Horse owners often wonder whether their horse needs to gain weight or add muscle—or both. Understanding the difference between body condition and muscle is crucial for developing the correct feeding and training strategies.
In this article, we’ll explain how to evaluate body condition, recognize signs of poor muscling or body condition, and share practical nutrition strategies to help your horse look and perform its best.
What Is Body Condition in Horses?
Body Condition Score (BCS) is a system developed by Dr. Don Henneke at Texas A&M to evaluate fat coverage in horses. BCS is a key tool for managing weight, nutrition, and performance.
BCS measures fat, not muscle. However, the energy reserves it reflects are essential for supporting muscle development.
A score of 4–6 is generally considered a healthy BCS. The 1–9 scale below measures subcutaneous fat deposits in six key areas: the neck, withers, ribs, tailhead, shoulders, and along the spine.
- 1 (Poor): Emaciated. No fatty tissue, ribs, spine, or hip bones are highly prominent.
- 2 (Very Thin): Very little fat. Slight fat is visible over the spine and ribs, and the bones are still clearly visible.
- 3 (Thin): Fat beginning to build over the ribs and tailhead, but spine and withers remain sharp.
- 4 (Moderately Thin): Negative crease along the back, ribs faintly visible, fat felt around the tailhead.
- 5 (Moderate): Ideal BCS for most horses. Back is flat, ribs easily felt but not seen, slight fat around withers, shoulders, and tailhead.
- 6 (Moderately Fleshy): May see a slight crease down the back, ribs felt with some pressure, fat deposits more noticeable along the neck and tailhead.
- 7 (Fleshy): Crease down the back, difficult to feel ribs, fat around neck, withers, and tailhead more pronounced.
- 8 (Fat): Prominent crease down the back, ribs not felt, thick fat deposits over neck, withers, shoulders, and tailhead.
- 9 (Extremely Fat): Considered obese. Noticeable crease down the back, extensive fat covering all key areas, bulging fat pads, especially at the tailhead.
How to Body Condition Score Horses
The Henneke Body Condition Scoring System is the traditional method for assessing a horse’s body condition, relying on both visual appraisal and palpation—an approach that is particularly essential for horses with thick coats.
Fat cover is best assessed over the ribs. For example, at a BCS of 5, ribs aren’t visible but can be felt with light pressure.
However, the limitation of this system is that it only measures fat and does not account for topline muscling or uneven fat deposits, both of which are important indicators of overall wellness.
That’s why Tribute® Equine Nutrition uses the Wellness System, which separately scores body condition, topline muscling, and the presence of fatty deposits along the crest—essential markers of ideal health. You can learn more about body scoring using Tribute Equine Nutrition's Wellness System.
Signs a Horse Needs to Gain Body Condition
When evaluating body condition, regular assessments help distinguish an underweight horse from one that is simply lean and fit. Ideal scores vary by breed and discipline, but horses with a BCS of 4 or lower generally need to gain weight.
Still, since weight loss can signal health problems, it’s essential to consult a veterinarian to rule out underlying causes. The following signs can indicate low body condition:
- Ribs: Easily seen and felt, no fat cover.
- Topline and Back: Prominent spine, little fat or muscle.
- Tailhead and Hips: Tailhead and hip bones are sharply visible.
- Neck and Withers: Thin or “ewe-necked,” and sunken withers.
- Shoulders: Angular and stand out.
- Overall Appearance: Gaunt, bony, drawn up in the flank.
- Performance: Low stamina and poor athletic output.
- Energy and Behavior: Weak, lethargic, reluctant to move.
- Coat and Hooves: Dull coat, brittle hooves.
- Fit vs. Malnourished: A race-fit horse shows muscle and energy, while a malnourished horse looks sunken, weak, and lacks both fat and muscle.
How Horses Build Muscle
Muscle development in horses relies on three key factors: balanced nutrition, progressive exercise, and proper recovery. Exercise creates microscopic muscle tears, which are repaired and strengthened when the horse has enough protein, amino acids, and energy.
Training type and frequency also play a role. Progressive training—gradually increasing intensity—stimulates further muscle growth. Proper warm-ups, cool-downs, and rest days also support muscle recovery and overall well-being.
Specific nutrients, particularly essential amino acids such as lysine, methionine, and threonine, are crucial for efficient muscle growth and development. Customizing a nutrition and conditioning program to a horse's individual needs helps maximize muscle development.
Signs Your Horse Needs More Muscle
Recognizing when a horse lacks muscle is just as important as monitoring fat cover. The following signs can help you determine if your horse needs more muscle development:
- Flat or Hollow Topline: The back looks sunken rather than rounded, with little muscle along the spine.
- Poor Saddle Fit: Lack of topline muscle causes the saddle to bridge or pinch, leading to discomfort.
- Weak Hindquarters: Limited muscle reduces power for transitions, jumping, or pushing off the ground.
- Balance Issues: The horse struggles to carry itself, often traveling on the forehand.
- Difficulty with Collection: Insufficient muscle makes it hard to engage the hind end and lift the back.
- Overall Appearance: Horse looks thin despite adequate fat cover, showing a lack of muscling rather than poor body condition.
Nutrition for Improving Body Condition and Muscle in Horses
Improving body condition and muscle often go hand in hand, but they require different strategies. Horses need adequate body condition before they can build muscle—without enough calories and protein, even consistent exercise won’t lead to topline development.
A balanced diet with sufficient energy, quality protein, and essential amino acids supports both recovery and muscle growth. Feeding concentrates at rates below the recommended amount can cause nutrient gaps, so it’s crucial to meet these feeding guidelines or add a ration balancer.
Horses with a low BCS often appear thin and under-muscled due to a lack of energy reserves, while a healthy BCS shows appropriate fat cover and good muscle tone. Appearances, however, can be misleading—some horses carry excess fat that hides poor muscling, while others may look thin despite adequate fat because of a weak topline. Fat is stored energy, while muscle is active tissue developed through proper nutrition and exercise.
Nutrition for Improving Body Condition
For underweight horses, the goal is slow, steady weight gain. On average, a 1,100-pound horse requires approximately 60 days to gain one BCS point, or roughly 45–50 pounds.
High-quality forage should always be the foundation, with leafy, nutrient-rich options like alfalfa providing both calories and digestive support. Calorie-dense feeds can also deliver safe, slow-release energy, while senior feeds supply highly digestible calories for older horses.
Any dietary changes must be made gradually over 10–14 days, with progress tracked regularly using weight tapes, photos, or scales. Before making any dietary changes, it's ideal to consult a veterinarian to rule out underlying issues such as dental problems, ulcers, or parasites.
Nutrition Strategies for Building Muscle in Horses
To build muscle, horses need more than just calories—they require the right balance of nutrients and exercise.
High-quality forage should always be the foundation of the diet, supported by a balanced concentrate or ration balancer. The goal is to supply nutrients in the right proportions to encourage topline and muscle growth while preventing excess fat gain.
Protein quality is essential for muscle development, particularly amino acids like lysine, methionine, and threonine, which are often lacking in forage. These amino acids enable the rest of the dietary protein to be utilized more efficiently for muscle building.
Vitamins and minerals are equally essential—vitamin E supports recovery, selenium protects muscle cells from oxidative stress, and calcium and phosphorus are critical for proper muscle function.
When horses are fed below the recommended rate of grain concentrate or rely on poor-quality forage, amino acid intake may be deficient. A ration balancer such as Essential K® can be an ideal way to supply essential nutrients and amino acids, supporting optimal muscle development.
Common Mistakes Horse Owners Make When Building Muscle and Improving Body Condition
Feeding missteps are surprisingly common. Here are some of the top pitfalls when trying to build a horse's muscle or body condition:
- Feeding by scoop, not weight: This leads to under- or overfeeding since volume doesn’t equal accurate nutrition. You can learn more about feeding by weight, not by scoop, here.
- Incorrect feeding rates: Offering less than the recommended amount of grain concentrate can cause vitamin and mineral gaps.
- Skipping forage analysis: Without testing hay or pasture, energy and nutrient intake are often misjudged.
- Underfeeding forage: Too little forage increases the risk of digestive issues such as colic and gastric ulcers and can negatively impact a horse’s body condition.
- Overloading supplements: Adding supplements as a “patchwork” fix, rather than first balancing the base diet with quality forage and full-intake concentrates.
- Inadequate Nutrients Versus Calories: Calories alone don’t build muscle—quality protein, amino acids, and minerals matter along with exercise.
- Not adjusting for lifestyle changes: Feeding the same ration year-round without adjusting for changes such as workload, life stage, or season.
Evaluating and Improving Body Condition and Muscle With Tribute Nutrition
While an on-site assessment is always preferred, it isn’t always possible. The Tribute Nutrition team often completes diet evaluations remotely. We request recent photos during remote assessment to help us determine whether a horse truly lacks body condition or if it appears thin due to poor muscling, despite having adequate fat cover. Seeing the horse’s current condition allows us to make the most accurate and effective diet recommendations.
Tribute offers targeted solutions by recommending the best grain concentrate or ration balancer tailored to each horse’s age, workload, body condition, and muscling. A balanced diet and the right product ensure your horse receives the support it needs to look and perform its best.
If you’d like to have your horse’s diet evaluated to improve body condition, muscle, or both, please reach out to our team for a free, personalized feeding plan tailored to your goals and your horse’s unique needs.
References
Hiney, K. (2024, October). Body condition of horses (Fact Sheet AFS-3920). Oklahoma State University Extension.
Available at https://extension.okstate.edu/fact-sheets/body-condition-of-horses.html
Hathaway, M., Catalano, D., & Martinson, K. (Reviewed 2024). Caring for the underweight horse. University of Minnesota Extension.
Available at https://extension.umn.edu/horse-health/caring-underweight-horse
Skelly, C. (2013, February 19). Determining the Optimal Body Condition Score for Your Horse. Michigan State University Extension.
Available at https://www.canr.msu.edu/news/determining_the_optimum_body_condition_score_for_your_horse
Tennessee Extension. (2023, October). Publication SP782. University of Tennessee Institute of Agriculture.
https://utia.tennessee.edu/publications/wp-content/uploads/sites/269/2023/10/SP782.pdf
