Our equestrian industry is riddled with anxiety of many forms, and the "equine nutrition" anxiety form is one of the most common. What causes this anxiety? The wealth of advertisements and opinions. Does your trainer think your horse is fat and your veterinarian thinks it's too thin? Are you worried about your horse's risk for laminitis? Or worried about losing muscle along the topline? It's hard to be unbiased about what is too little, too much or just right, but there are very real antidotes to this anxiety. We can add objectivity to subjectivity with one of several scoring systems.
INTRODUCTION
The majority of horse owners that I talk to have a little to a lot of anxiety about the accuracy, cost, and complexity of their horse’s diets. But hidden amongst the advertisements, feed labels and wealth of opinions are multiple cures to this lack of confidence. The three little Xanax-like cures include scoring, weighing and forage testing. Last month, I talked about how to test your hay. This is the gold standard in removing the guesswork. I've also discussed the many ways you can estimate your horse's true weight in "Frustrations About Weight" (September 2021). So today, we’ll be discussing the third method of minimizing anxiety about your horse’s diet- scoring. We’ll discuss the three research driven scoring systems used in equine health today- muscle mass scoring, body fat scoring, and cresty neck scoring.
The first thing that I want to tell you about these systems is that they are imperfect. They are very blunt tools in the dissection of your horse’s perfect diet. However, it’s also easy to overlook the power of these systems due to their simplicity, but they are more nuanced and helpful than they first appear. It’s often shocking to me, how an explanation of body condition versus muscle mass score can put an owner at ease. Putting numbers to facts and facts to opinions is like pulling the curtain back on a magic trick. Numbers don’t have opinions, and anxiety is banished. So, let's pull back the curtain!
Body Condition Scoring
There is more than one scale used to body condition score horses, but I’m only going to describe one, the Henneke Body Condition Scoring System (HBCSS), because it is the most commonly used amongst nutritionists, veterinarians, and horse rescues. There are over 1,310,000 hits on Google about this BCSS, so I’m only going to describe the high level necessary details, and then I HIGHLY encourage you to do some additional research and active practice. And I do mean practice in the way that you repeat a barrel pattern or dressage test, because research has shown that most horse owners are poor users of this system. Remember how I said that these systems are more nuanced than they first appear? This is especially true for the HBCSS.
The HBCSS was designed by Dr. Henneke out of Texas A&M back in the 1980's. It’s a non-biased method of visually discerning adiposity. Let me say it in another way- it’s a way to measure the amount of fat your horse has deposited over his musculoskeletal system. Let me repeat one more time- it’s about fat deposition. It is not about muscle, conformation, body type, breed, age or sex. The most common error that horse owners new to this system make, is that they confuse fat deposition with these other traits. Here’s a short list of equine traits that are commonly mistaken for body fat.
The hay belly appearance.
The naturally arching necks of certain Baroque breeds, warmbloods and stallions.
Conformation- Wasp wasted versus well sprung barrels can create illusions.
Heavily muscled breeds like Quarter Horses are generally under rated.
Muscle atrophy versus body condition of geriatric horses.
When you "want" that fat to be muscle.
The anecdote to confounding traits is practice with a lot of different types of horses. In order to train to eye, you must have a broad perspective on breed types, conformation mirages, as well as understanding of where horses deposit fat. They deposit it over their top lines; from the crest of the neck, down the withers and back, over the ribcage and to the tail head. Many breeds also tend to deposit fat behind the shoulder blade about where your girth or cinch buckles. Use the flat of your hand and your fingers to caress and probe these areas. Can you easily feel the ribs under the skin but not SEE them when the horse is standing quietly, relaxed and fully hydrated? This is a perfect 5 on the scale from 1-9. Anything between 4-7 is considered healthy. You can have a very fit racehorse, ribs easily visible, no additional fat, but not emaciated. A score less than 4 is considered too thin and can lead to hormone problems and loss of muscle mass. A score over 7 is considered obese. A 9 on the scale represents the most rotund little mini you've ever seen on who's butt cheeks you can pool water!
STEPS TO USING THE HENNEKE BODY CONDITION SCORING SYSTEM
Stand your horse on level ground where he/she can be relaxed and calm. You want their muzzle to be about level with the point of their shoulder. Make sure that they are hydrated. Dehydration, such as that moment they step off the horse trailer after a long ride, can confound results.
Start by taking the flat palm of your hand and place it just below the ridge of the withers where the shoulder blade makes a pocket. Then, rub your hand down the top of their ribcage and feel for ribs. Again, if you can feel them easily under the skin, then it's a 5 or less. If you have to probe for ribs under a cover of fat, then it's a 6 or greater. The more aggressively you have to probe, the higher the BCS.
Pinch the crest of the neck feeling for fat versus muscle. Muscle is hard. Fat is spongey.
Rub your palm over the topline from withers to tail checking for fat deposits over the spinous process and on either side of the croup. Fat pockets can form over the tail head.
Check behind the shoulder blade (F in the diagram). Fat pockets can form there as well.
The greatest gift of the HBCSS is how it brings objectivity to subjectivity, numbers to heresy and relief to your "don't know what I don't know" anxiety. Start by heading to Google, type in Henneke Body Condition Scoring and study the many different charts that are available. There is a well-done poster you can purchase at TheHorse.com- CLICK HERE.
Muscle Scoring System(s)
Muscle Scoring Systems are moderately useful to horse owners who want to "improve their horses' toplines". This is a very common request in my line of work. The first concept to understand is that changing your horse's body condition score and changing their musculature are two completely separate nutrition goals! We feed for each goal slightly differently; changing a body condition score is about calories in versus calories out while changing musculature involves providing a specific group of nutrients and/or nutraceuticals that are necessary for muscle development AND THEN quality work. The second concept to understand, and it should be obvious, is that you can not feed muscles to be bigger like an air pump in a bike tire. You must WORK those muscles to make them larger or more efficient. Nutrition simply provides the building blocks. With those two very important concepts in mind, let's take a look at two muscle scoring systems- the Muscle Atrophy Scoring System (MASS; Herbst et al., 2022) and the Muscle Score system by Walker et al. (2016).
Muscle scoring systems are relatively new tools in your horse owner toolbox. A study published just this year, 2022, by the University of Kentucky has helped quantify muscle atrophy in horses. It appears that their primary motivation was to provide tools for assessing the aging horse and horses suffering from PPID. This scoring method runs from 1-4 with the highest scores having the greatest degree of muscle atrophy defined as "below normally accepted levels" (Herbst et al., 2022). They call this system the Muscle Atrophy Scoring System (MASS) and did a great deal of work to dummy-proof their methods. For example, before the horses were assigned a score between 1 and 4, they were divided into either "lean" (BCS <5) or "adipose" (BCS >5) using the above mentioned Body Condition Scoring System. By doing so, the raters could build in an adipose bias to their system.
As you can see from the photos below, the system is a little bit cumbersome. Researchers have not only divided horses into lean and adipose categories, but then there are 4 different areas of the body to evaluate (i.e. neck, back, abdomen, and hind), and a score to give to each. Since this scoring system is so new, it is yet to be determined how much it gets used in the field. I expect that this system will be quite useful for owners struggling with elderly and PPID horses, but less meaningful to owners with an average, healthy, performance horse. It could also be useful to help trainers, veterinarians, and saddle fitters communicate muscle atrophy problems related to back pain (i.e. poor saddle fit, poor riding, kissing spine, ect). Like the body condition scoring system, it will take some active practice to perfect.
You can read the scientific article about MASS on THIS LINK HERE.
The MASS study from University of Kentucky compared their methods to a 2016 study by a United Kingdom group who were relating muscle scoring to gait patterns exclusively in dressage horses. They performed visual, tactile, and high speed motion capture evaluations on 35 horses from beginning training up to Grand Prix. They split the muscled areas into neck, thoracic, lumbosacral, pelvic, hindlimb and abdominal. What is interesting about their results is that they correlated better muscle scores of the thoracic, abdominal and lumbosacral areas with desirable gait patterns like elevation of the forehand and greater flexion of joints. They concluded that greater spinal STABILITY through muscle development was key to success. This seems intuitive, but it's nice to put some statistical analysis to the age old debate over the ultimate aim of dressage work.
Reading this research paper is a bit like trying to see the forest through the trees. It's hard to determine what to focus on, but what I concluded is that we're really only at the beginning of placing numbers to equine musculature. These systems are rough estimates and should be used with the greatest amount of commonsense derived from the unique situation(s) of the individual.
You can read the scientific article about this system on THIS LINK HERE.
Cresty Neck Scoring
Cresty neck scoring (CNS) was added to the list of scoring systems back in the late 2000's in response to the rising tide of obesity and obesity related metabolic disease in horses, ponies and donkeys. It was designed to compliment the BCSS and correct for some of its limitations. One such limitation is the unusual regional adiposity seen in cases of insulin resistance or equine metabolic syndrome (these terms are often used interchangeably) which sometimes conflict with fat deposited in other areas of the body. Because overweight/obese horses and horses with severe regional adiposity are at greater risk for laminitis, these scoring systems are important signaling tools for horses at risk (Carter et al., 2009). What's super interesting is that a study published in 2019 confirmed that CNS scores were more predictive of insulin resistance (confirmed by oral glucose test) than the BCSS was which gives nutritionists, veterinarians, and owners a sharper tool in their toolbox (Fitzgerald et al., 2019)!
The CNS system uses numbers between 0 and 5 with the higher numbers representing higher accumulations of fat along the nuchal crest of the horse. The above image is an easy visual for scoring. This system is simple, easy to use and applicable to many breeds at higher risk for laminitis such as drafts crosses, ponies, minis, and donkeys. Every horse owner should be aware of this system and practice it often. Like the BCS system, research has shown that owners have difficulty using this system reliably without compounding other factors like hair coats in winter (Giles et al., 2015). I had a client this year who took the CNS system one step further and started measuring the diameter of her donkey's cresty neck with a simple, inexpensive caliber tool. The larger the donkey's crest grew, the more caution she took to monitor his diet and turnout. I thought that this was very smart!
SUMMARY
Well there you have it- the three scoring systems available to you for taking the guesswork out of your horse's health and nutrition planning. I use these systems every single day during consultations and find them surprisingly helpful to clients. It's good to estimate your horse's current weight, but it's even better to pair that weight with a direction; either to increase weight, decrease weight or to stay the same. Start by giving your horse a body condition score, muscle score, and/or cresty neck score and then set a timeframe for a reasonable amount of change depending on the season and level of activity. During a 3 Month Guided Nutrition Practice by OCEN, LLC, I wouldn't expect a horse to gain or lose more than 1 body condition score during that 90 day period, and know that's its easier for horses to gain weight than lose weight just like humans! Combine these scoring systems with a representative forage test and you really couldn't get more prepared! That is the truer course towards becoming a savvy horse feeder! Get off those supplement webpages, print out the scoring system charts, and get outside with your horse!
Related Posts
"How to test your hay"- November, 2022 by OCEN, LLC
"Frustrations about weight"- September 2021 by OCEN, LLC
REFERENCES
Carter, R.A., Geor, R.J., Staniar, W.B., Cubitt, T.A. and Harris, P.A., 2009. Apparent adiposity assessed by standardized scoring systems and morphometric measurements in horses and ponies. The Veterinary Journal, 179(2), pp.204-210.
Fitzgerald, D.M., Anderson, S.T., Sillence, M.N. and de Laat, M.A., 2019. The cresty neck score is an independent predictor of insulin dysregulation in ponies. Plos one, 14(7), p.e0220203.
Giles, S.L., Nicol, C.J., Rands, S.A. and Harris, P.A., 2015. Assessing the seasonal prevalence and risk factors for nuchal crest adiposity in domestic horses and ponies using the Cresty Neck Score. BMC veterinary research, 11(1), pp.1-9.
Herbst, A.C., Johnson, M.G., Gammons, H., Reedy, S.E., Urschel, K.L., Harris, P.A. and Adams, A.A., 2022. Development and evaluation of a muscle atrophy scoring system (MASS) for horses. Journal of Equine Veterinary Science, 110, p.103771.
Walker, V.A., Tranquille, C.A., Dyson, S.J., Spear, J. and Murray, R.C., 2016. Association of a subjective muscle score with increased angles of flexion during sitting trot in dressage horses. Journal of Equine Veterinary Science, 40, pp.6-15.
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