CFAES Give Today
Ohioline

Ohio State University Extension

CFAES

Evaluating Body Composition of Horses

AS-1024
Agriculture and Natural Resources
Date: 
06/27/2022
Sara L. Mastellar, PhD, Equine Faculty, Ohio State University Agricultural Technical Institute
Elizabeth Share, MS, 4-H Livestock Program Specialist, The Ohio State University
Haley M. Zynda, MS, Educator, Ohio State University Extension, Wayne County

Nutrition and feeding management support all aspects of a horse’s health and welfare. Regular evaluation of the horses in your care can help you identify potential issues before they develop further, as well as monitor progress toward a healthy physique. This fact sheet details how to measure and evaluate equine body weight, fat storage (i.e., body condition scoring), and muscling.

There are many clues that indicate to an owner/manager they may need to adjust a horse’s diet. Knowing what to look for can inform nutritional decisions, determine when to involve a qualified nutritionist and identify if an improvement has been made. The effect of dietary changes on the horse, such as shifts in the body composition, are often slow. Keeping photographic and written records of each evaluation can assist in monitoring such changes. Among the assessments a horse owner/manager can use are body weight, body condition scoring (BCS), cresty neck scoring (CNS), muscle evaluation, and general health observations.

Body Weight

What This Information Means

Knowing your horse’s weight allows more accurate calculations of nutritional requirements and drug dosages, such as for dewormer. Knowing if your horse is gaining or losing weight over time will help you make appropriate management adjustments.

Other Factors Besides Diet Influencing Body Weight:

  • activity level
  • genetics (e.g., breed size)
  • parasite load
  • metabolic issues
  • cardiac issues
  • cancer
  • other illness

How to MeasureFemale college student holding the reins on a horse being weighed on a scale.

The most accurate way to measure body weight is by using a scale (Figure 1). Horses can be trained to walk onto livestock scales, or you can drive a truck and trailer onto a vehicle scale with and without the horse and subtract the vehicle’s weight to determine the horse’s weight. However, not all farms have easy access to a scale.

Weight tapes can be used to estimate body weight. Use according to directions on the tape and be consistent as there may be slight variations between different brands. Always using the same spot on the withers will more accurately track changes over time. Weight tapes usually give an estimate that is lighter than the actual weight as measured by a scale (unpublished data). However, this varies from horse to horse.

If you do not have access to either a scale or a weight tape, you can use a formula to estimate your horse’s weight. Some formulas are more accurate for certain breeds or types of horses due to their differing conformation. One of the most commonly used formulas is below. Measure both body length (BL) and heart girth (HG) in inches to obtain a body weight in pounds (Figure 2).Graphics overlaid on horse  indicate how to measure the heartgirth circumference and the body length of the horse.

(HG2 x BL)/330 = BW (lb.)

Body Condition Scoring (BCS)

What This Information Means

Body condition scoring is a measure of fat cover and storage on the body (Henneke et al. 1983). Scoring is based on visual appraisal and touch (particularly in scoring horses with long hair coats). Conformation differences between breeds or types do not affect scoring when all criteria are applied. Muscle tone should not be confused with fatness. Although, if the horse does not have enough calories in its diet to have fat storage/cover, it may not have the calories to support desirable muscling. In the US, typically the 1 to 9 Henneke scoring system is used for horses, while in other countries and in other species 1 to 5 scoring systems are common. In this fact sheet, we will focus on using the Henneke 1 to 9 scoring scale.

Different management strategies and riding disciplines may prefer a slightly different BCS from the “ideal” of 5. For example, Thoroughbreds in heavy race training may have a BCS of 4, ideal for their situation, but potentially not in the case of a retired geriatric horse headed into winter, where a BCS of 6 may be more appropriate.

Most of the domestic horse population is overweight or obese and the problem has worsened over time (Thatcher et al. 2008; Thatcher et al. 2012; Martinson et al. 2013), likely because most owners/managers underestimate the amount of fat their horse carries (Potter et al. 2016).

Over-conditioned horses are more likely to suffer from metabolic issues, heat exhaustion, poor performance, and joint problems, such as arthritis. In one study, when horses carried more body fat, they had more movement asymmetry (Jansson et al. 2021). Under-conditioned horses are more susceptible to disease and heal more slowly from injuries. Additionally, low body condition can mean there is an underlying health issue, such as a high parasite load. Adjusting calorie intake and workload, while meeting other dietary and welfare requirements, will influence BCS. If reducing calorie intake, work with a qualified nutritionist in identifying a diet that maximizes chewing time to reduce boredom and minimize the risk of developing gastric ulcers (Shepherd et al. 2021). Other factors besides diet can influence BCS, including those previously listed for body weight.

How to MeasureFull side view of a horse with annotations identifying areas, the names of body areas, and skeletal anatomical markers.

There are six areas to evaluate where horses store fat (Figure 3; Table 1). Just like humans, individual horses store more fat in some areas than others. There is no one best area to begin scoring; scoring may start at any of the six points on the horse. However, a consistent “front to back” approach can help scorers make sure that no area is missed. Score each area individually and then average the scores. Scores may be assigned in half-point increments.

Note: Donkeys suffer from many of the same issues as horses, but donkey body condition scoring is done differently because these animals carry fat in different areas (Pearson and Ouassat 2000). Be sure to use a donkey specific condition scoring system when evaluating those animals. Mule owners should be aware of body condition scoring systems for both horses and donkeys.

Description of the areas to be scored when body condition scoring a horse, including the neck, along the withers, behind the shoulder, the ribs, the loin, and the tailhead.

Table 1 (PDF download). Description of the areas to be scored when body condition scoring horses.
Adapted from Henneke et al. (1983) similar to a previous factsheet from Utah State University by Hoopes et al. (2019).

Cresty Neck Scoring (CNS)

What This Information Means

Cresty neck scoring (0–5 scale) is another measure of adiposity (fat) but focuses on where fat is stored in the body (Carter et al. 2009). It is similar to the neck sub-score for BCS. Horses, and especially ponies, with cresty necks (scores of 3 or greater) are at risk for metabolic issues (Fitzgerald et al. 2019), including laminitis. A BCS of 5 is likely associated with a CNS of 2.

Other Factors Besides Diet Influencing CNS

  • any factor that can affect BCS
  • genetics (Some breeds, such as Morgans or ponies, are predisposed to having cresty necks and associated metabolic issues (Norton et al. 2019).)

How to Measure

Evaluate the neck visually and by palpation (touch). Underlying muscling can give the appearance of a neck crest, especially in stallions or horses that participate in certain disciplines. Be sure to focus on the fat deposit portion of the neck. The fat deposit is largely above the nuchal ligament, which runs from the poll (top of the head) to the withers. Determine which score description and picture most closely match the horse that you are evaluating (Figure 4).

Five numbered photos displaying the side view of five different horses’ head and neck area. Each photo depicts how a fat deposit appears along the neck crest, with ratings from 0 (no crest) to 5 (excessively cresty).

Muscling Evaluation

What This Information Means

Muscling is different from “condition” or fat storage. However, horses that are energy deficient will break down their own muscle tissue to use as energy to maintain other body systems.

Muscle evaluation systems for horses are newer than BCS. However, you should be monitoring muscling responses to activity/training and diet. Feeding management, such as where feed is placed (floor vs raised feeder), and voluntary activity will affect the horse’s posture (Raspa et al. 2021), both of which can potentially affect long term muscle development. In addition, the type and quality of a horse’s workload will affect muscle development (Walker et al. 2016). Ill-fitting tack and equipment can interfere with desired muscle development, too (Dyson et al. 2015). However, without the proper nutritional building blocks, a horse cannot build muscle. Principally, protein or amino acid deficiency can negatively affect the horse’s ability to build muscle (Graham-Thiers and Kronfeld 2005). Also, vitamin E deficiency can result in muscle atrophy associated with equine motor neuron disease (Divers et al. 2006). In addition to amino acids and vitamin E, dietary carbohydrates, fat, macrominerals, and selenium support muscle function (Urschel and McKenzie 2021). Macro- and micronutrients are discussed further in fact sheets titled “The Role of Macronutrients in Equine Nutrition” and “The Role of Micronutrients in Equine Nutrition.”

Other Factors Besides Diet Influencing Muscling:

  • activity level and type
  • genetics
  • age
  • hormones (e.g., stallions v. geldings)
  • feeding management
  • saddle/equipment fit
  • pain (e.g., lameness or back pain)
  • neurologic issues
  • Pituitary Pars Intermedia Dysfunction (PPID, previously known as Cushings)
  • conformation

How to Measure

Muscle evaluation should be conducted only after BCS is determined so scorers have an appreciation of how much fat the horse is storing and where. There are three approaches to muscle scoring/evaluation (Figure 5). The first system (Table 2), developed for dressage horses in work, focuses on muscle development (i.e., strengthening via training) and was created by Walker et al. (2016). The second system, Muscle Atrophy Scoring System (MASS; Table 3), was developed for idle horses to detect atrophy or muscle loss (Herbst et al. 2021). The third and most simplistic approach focuses only on the topline of the horse.

How a horse stands can influence muscle appearance. Take note of how your horse is standing and try to have it in a similar position each time to give yourself the best chance of noticing differences over time. Ideally, the horse should stand on a flat surface comfortably square with head and neck aligned with the back instead of bent to the side. The jawline and underside of the neck should create a 90-degree angle with the nose level to the point of shoulder. Be sure to evaluate both sides because asymmetry could indicate an underlying issue.

Graphic detailing how to body condition score a horse’s neck, back, and hind when the horse is working or idle.

Horses in work should be developing muscle, which would be reflected as increases in their “in work” muscle scores (1 = least muscled to 5 = most muscled). For idle horses, increases in atrophy score when using the Muscle Atrophy Scoring System (MASS; 1 = no atrophy to 4 = severe atrophy) indicate an underlying problem. If only conducting topline evaluation scoring, a score of “A” is considered ideal and a score of “D” is poor.

If using either muscle scoring or MASS, evaluate the different muscle groups shown in Figure 6 using the appropriate charts. When using MASS, the pelvic and hindlimb areas are scored together as the “hind.”

The following definitions may be helpful in interpreting the descriptions in the muscle and atrophy evaluation charts.

  • caudal - Toward the tail.
  • cervical - Neck.
  • cranial - Toward the head.
  • dorsal - Topside or side that includes the back.
  • greater trochanter of the femur - Protrusion on the long bone in the thigh of the horse (Figure 3).
  • palpation - Evaluated by feel/touch.
  • spinous processes - Protrusions and wing-like projections of the vertebrae.
  • transverse - Extending horizontally, as opposed to vertical, such as the wings of some vertebrae.
  • tuber coxae - Protrusion of the pelvis on the side of the horse (Figure 3). Sometimes referred to as the “point of hip” and known as “hook bones” in cattle.
  • tuber ischii - Protrusion of the pelvis at the back of the horse (Figure 3). Sometimes referred to as the “point of buttock” and known as “pin bones” in cattle.
  • tuber sacrale - Protrusion of the pelvis at the end of the loin and beginning of the croup of the horse (Figure 3).
  • ventral - Underside or belly side.

Side view of horse with graphic overlay identifying the muscle areas to score using the Muscle Atrophy Scoring System.

First worksheet used to muscle score horses' neck, thoracic,  and lumbosacral regions.
First worksheet used to muscle score horses' pelvis, hindlimb,  and abdominal regions.

Table 2 (PDF download). Muscle scoring for horses in work. Adapted from Walker et al. (2016).

Worksheet that provides guidance on how to score muscle atrophy in idle horses. Adapted from Herbst et al. 2021.
Table 3 (PDF download). Muscle Atrophy Scoring System (MASS) for idle horses. Adapted from Herbst et al. (2021).

Topline scoring is a method that has been used by feed companies to help customers gauge muscling of their horses. The topline evaluation system (Figures 7 and 8) was developed by Progressive Nutrition with scores ranging from A “ideal” to D “atrophied” (Smith 2016; Walker and Daniels 2019).

 Horse’s body with overlaid graphic identifying wither and back, loin, and croup muscles that should be scored using the topline evaluation system.

Look at and feel muscling along the wither, back, loin, and croup. Determine which score description and picture most closely match the horse you are evaluating (Figure 8).

Photos of four horse’s bodies, showing ideal, adequate, sunken, and poor muscle condition.

General Health Observations

There are many other indicators that a horse’s diet is not ideal. These include:

  • Low energy level, poor attitude, and sub-optimal performance can be a result of poor diet or feeding management.
  • Frequent colic could mean there is inadequate fiber to support healthy gut motility, foreign material in the diet (e.g., sand), or inadequate water intake. There are many other causes of colic too.
  • Poor fecal quality may suggest gut disturbances (e.g., microbiome dysbiosis).
  • Hoof quality is supported by the diet, but is also affected by the time of year, disease, age, stress, moisture/dryness of the environment, and hoof care.
  • The hair coat, mane, and tail quality are all supported by the diet, but can also be affected by grooming, time of year, and disease.
  • Tearing of the eyes can indicate a vitamin deficiency, among many other things.
  • Subfertility can be a symptom of vitamin and mineral toxicities, deficiencies, or imbalances. Energy status and body condition score also play a role in fertility.

If you notice that your horse has any of these issues, consider contacting a qualified nutritionist or veterinarian to perform a more thorough assessment on your horse, its diet, and your feeding management (Hesta and Shepherd 2021). Veterinarians should be included in the conversation if there is evidence of an underlying issue (e.g., metabolic issue, disease, or parasite problem) in addition to nutrition. These professionals should have a working knowledge of the equine digestive system and its limitations to help design diets that not only meet nutrient requirements, but also promote welfare (Harris and Shepherd 2021). The example body composition record (Figure 9) can be used to document all the areas discussed and serve as a record to monitor change over time. Consider also keeping photos of your horse with your records.

Figure 9. Body composition record worksheet to record a horse's name, evaluation date, body length, girth, and weight, as well as body condition scoring, fat evaluations, and muscle evaluations.

Figure 9 (PDF download). Example body composition record.

Take-Home Message

Nutrition and feeding management support all aspects of a horse’s health and welfare. Regular evaluation of the horses in your care can help you identify potential issues before they develop further as well as monitor progress toward a healthy physique.

Acknowledgments

The authors thank Josephine Shaya, Associate Professor of Classical Studies; Department Chair of Archaeology at the College of Wooster, for her thoughts on making the document more understandable and useful for horse owners without a background in animal science. The authors also thank Dan Rhodeback, Facility Manager, and Erica Kight, Herd Manager, of Ohio State’s Columbus Campus Equine Facility for their perspectives on improving the document.

References

Carter, R. A., R. J. Geor, W. Burton Staniar, T. A. Cubitt, and P. A. Harris. 2009. “Apparent Adiposity Assessed by Standardised Scoring Systems and Morphometric Measurements in Horses and Ponies.” The Veterinary Journal, Volume 179, Issue 2: 204–210.
pubmed.ncbi.nlm.nih.gov/18440844/.

Divers, T. J., H. Mohammed, H. Hintz, and A. De Lahunta. 2006. “Equine Motor Neuron Disease: A Review of Clinical and Experimental Studies.” Clinical Techniques in Equine Practice, Volume 5, Issue 1: 24–29.
doi.org/10.1053/j.ctep.2006.01.005.

Dyson, S., S. Carson, and M. Fisher. 2015. “Saddle Fitting, Recognising an Ill-Fitting Saddle and the Consequences of an Ill-Fitting Saddle to Horse and Rider.” Equine Veterinary Education, Volume 27, Issue 10: 533–543.
beva.onlinelibrary.wiley.com/doi/10.1111/eve.12436.

Fitzgerald, Daniel M., Stephen T. Anderson, Martin N. Sillence, and Melody A. de Laat. 2019. “The Cresty Neck Score is an Independent Predictor of Insulin Dysregulation in Ponies.” PLOS ONE, Volume 14, Issue 7: e0220203.
doi.org/10.1371/journal.pone.0220203.

Graham-Thiers, P. M., and D. S. Kronfeld. 2005. “Amino Acid Supplementation Improves Muscle Mass in Aged and Young Horses.” Journal of Animal Science, Volume 83, Issue 12: 2783–2788.
doi.org/10.2527/2005.83122783x.

Harris, Patricia, and Megan Shepherd. 2021. “What Would Be Good for All Veterinarians to Know About Equine Nutrition.” Veterinary Clinics of North America: Equine Practice, Volume 37, Issue 1: 1–20.
doi.org/10.1016/j.cveq.2020.11.001.

Henneke, D. R., G. D. Potter, J. L. Kreider, and B. F. Yeates. 1983. “Relationship between condition score, physical measurements and body fat percentage in mares.” Equine Veterinary Journal, Volume 15, Issue 4: 371–372.
doi.org/10.1111/j.2042-3306.1983.tb01826.x.

Herbst, Alisa C., Mackenzie G. Johnson, Hayley Gammons, Stephanie E. Reedy, Kristine L. Urschel, Patricia A. Harris, and Amanda A. Adams. 2021. “Development and Evaluation of a Muscle Atrophy Scoring System (MASS) for Horses.” J Equine Vet Sci, Volume 110: 103771.
doi.org/10.1016/j.jevs.2021.103771.

Hesta, Miriam, and Megan Shepherd. 2021. “How to Perform a Nutritional Assessment in a First-Line/General Practice.” Veterinary Clinics of North America: Equine Practice, Volume 37, Issue 1: 21–41.
doi.org/10.1016/j.cveq.2020.12.001.

Hoopes, K., E. Thacker, and L. Greenhalgh. 2019. “Body Condition Scoring for Horses.” Utah State University Libraries. Paper 2060.
digitalcommons.usu.edu/extension_curall/2060.

Jansson, Anna, Vikingur Gunnarsson, Sara Ringmark, Sveinn Ragnarsson, Denise Soderroos, Einar Asgeirsson, Tanja R. Johannsdottir, Charlotta Liedberg, and Guorun J. Stefansdottir. 2021. “Increased Body Fat Content in Horses Alters Metabolic and Physiological Exercise Response, Decreases Performance, and Increases Locomotion Asymmetry.” Physiological Reports, Volume 9, Issue 11: e14824.
doi.org/10.14814/phy2.14824.

Martinson, K. L., R. J. Coleman, A. K. Rendahl, and M. E. McCue. 2013. “The Over-Conditioned Horse: Incidence and Educational Opportunities.” Journal of Equine Veterinary Science, Volume 33, Issue 5: 366–367.

Norton, E. M., N. E. Schultz, A. K. Rendahl, D. McFarlane, R. J. Geor, J. R. Mickelson, and M. E. McCue. 2019. “Heritability of Metabolic Traits Associated with Equine Metabolic Syndrome in Welsh Ponies and Morgan Horses.” Equine Veterinary Journal, Volume 51, Issue 4: 475–480.
doi.org/10.1111/evj.13053.

Pearson, R. A., and M. Ouassat. 2000. “A Guide to Live Weight Estimation and Body Condition Scoring of Donkeys.” University of Edinburgh Scotland, Centre for Tropical Veterinary Medicine. PDF.
assets.publishing.service.gov.uk/media/57a08d7ced915d3cfd001a58/R6609c.pdf.

Potter, S. J., N. J. Bamford, P. A. Harris, and S. R. Bailey. 2016. “Prevalence of Obesity and Owners' Perceptions of Body Condition in Pleasure Horses and Ponies in South-Eastern Australia.” Australian Veterinary Journal, Volume 94, Issue 11: 427–432.
doi.org/10.1111/avj.12506.

Raspa, Federica, Angela Roggero, Claudia Palestrini, Martina Marten Canavesio, Domenico Bergero, and Emanuela Valle. 2021. “Studying the Shape Variations of the Back, the Neck, and the Mandibular Angle of Horses Depending On Specific Feeding Postures Using Geometric Morphometrics.” Animals, Volume 11, Issue 3: 763.
doi.org/10.3390/ani11030763.

Shepherd, M., P. Harris, and K. L. Martinson. 2021. “Nutritional Considerations When Dealing With an Obese Adult Equine.” The Veterinary Clinics of North America. Equine Practice, Volume 37, Issue 1:111–137.
doi.org/10.1016/j.cveq.2020.12.004.

Smith, Taryn Elizabeth. 2016. “Protein and Exercise Effects On the Musculature of the Back in Horses,” Graduate Thesis, Paper 2967. Missouri State University.
bearworks.missouristate.edu/cgi/viewcontent.cgi?article=3977&context=theses.

Thatcher, C., R. Pleasant, R. Geor, F. Elvinger, K. Negrin, J. Franklin, L. Gay, and S. Werre. 2008. “Prevalence of Obesity in Mature Horses: An Equine Body Condition Study.” Journal of Animal Physiology and Animal Nutrition, Volume 92, Issue 2: 222–222.
doi.org/10.1111/j.1439-0396.2007.00789_8.x.

Thatcher, C. D., R. S. Pleasant, R. J. Geor, and F. Elvinger. 2012. “Prevalence of Overconditioning in Mature Horses in Southwest Virginia During the Summer.” Journal of Veterinary Internal Medicine/American College of Veterinary Internal Medicine, Volume 26, Issue 6: 1413–1418.
doi.org/10.1111/j.1939-1676.2012.00995.x.

Urschel, Kristine L., and Erica C. McKenzie. 2021. “Nutritional Influences On Skeletal Muscle and Muscular Disease.” Veterinary Clinics of North America: Equine Practice, Volume 37, Issue 1: 139–175.
doi.org/10.1016/j.cveq.2020.12.005.

Walker, C., and S. Daniels. 2019. “How Repeatable is the Top-Line Evaluation System (TES)™ as a Palpable Muscle Scoring System for Horses?” Edinburgh International Conference Centre. The Proceedings of the British Society of Animal Science 2019 Annual Conference: Advances in Animal Biosciences, Paper 189.

Walker, V. A., C. A. Tranquille, S. J. Dyson, J. Spear, and R. C. Murray. 2016. “Association of a Subjective Muscle Score with Increased Angles of Flexion During Sitting Trot in Dressage Horses.” Journal of Equine Veterinary Science, Volume 40: 6–15.
doi.org/10.1016/j.jevs.2016.01.011.

Originally posted Jun 27, 2022.
Ohioline https://ohioline.osu.edu