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Carbohydrates in Equine Nutrition


This post was originally published back in January 2011, but I have had a number of questions regarding the overweight horse and carbohydrates in equine nutrition.  As a result, I am reposting.  If possible, print out the Equine Condition Scoring Chart and keep it handy at your barn for easy reference.  As horses are out in pasture during this time of year, we may want to review what we feed our horses so that we don’t have potential future problems.

In recent years, nutrition focus has seemed to have shifted to weight management and exercise for both people and horses.  I know that since I have been in the United Kingdom  and not riding my horses back home, both Bruq and Phantom have gained weight due to a lack of a regular exercise routine.  As a concern to me, there are some breeds of horses, such as the Arabian and Morgan, that are prone to such diseases as Insulin Resistance (IR) and Cushing’s, while other breeds  can be put at risk to many diseases resulting from being over weight.

My previous posting provided you with an Equine Condition Scoring Chart where you are able to score your horse  from 1-9, one being deathly thin and 9 being obese.  Once you have determined your horse`s condition score, you can take the necessary steps  to correct these conditions, or keep him at the optimum level.

Can overweight horses benefit from a low carb diet?

The term “low carbohydrate” diet in humans has become so very popular with the Atkins and South Beach diets focusing our attention on low carbs, and as a result many horse owners are also concerned about carbohydrates in their equine nutrition program. Happily, there has been recent research addressing the area of carbohydrates in equine nutrition and many feed companies are posting these values on their labels.  However, it is very important to keep in mind that when we look for low carbohydrate diets for our horse families, we also need to look at the sugar and starch levels as well in the  feeds.  These feedstuffs include forages (hay and pasture) as well as the ingredients that make up the concentrated feeds that we offer our horses.  These concentrated feeds include oats, corn, barley, beet pulp, soybean meal and the list goes on.

Nonstructural carbohydrates (NSC) are the sugars and starches found inside the plant cell of horse feeds. This is in contrast to the structural carbohydrates that compose the cell wall of the plants that our horses eat.  The two main cell wall components are cellulose and hemicellulose,  we know it as fibre.  This plant fibre is disgested thanks to the work of bacteria and protozoa living in the horse’s large intestine.  The horse receives his energy supply by taking up or absorbing  nutriants or organic acids in his large intestine.  The bacteria in the hindgut (large intestine) produce  organic acids from the fermentation of sugars that are released when the fiber is broken down by enzymes secreted by the bacteria and protozoa.

The sugars found in forages include glucose, fructose, sucrose and fructans. Starch is the major carbohydrate stored in the legumes of alfalfa, and warm season grasses such as bermuda grass and grains.  Fructans are the water-soluable sugars that are stored as the major carbohydrate in cool season grasses such as orchardgrass, fescue and timothy.

Research has shown that excessive intake of fructans from pasture grasses and grains can cause colic and laminitis (Hoffman et al, 2001).  The greatest danger of laminitis and founder for horses is the consumption of cool season grass pasture and hay which may contain high levels of sugar, especially large amounts of fructans.  Legumes or warm-season grasses contain little to no fructans.  For more information on the NSC value and fructans in grasses go to www.safergrass.org.    It is recommended that controlling the dietary NSC value to below 20% of the total diet is appropriate for problem horses afflicted with Cushing’s Disease, insulin resistance and equine diabetes (Longland & Byrd,2006) .

The table below outlines the sugar, starch and NSC values for feeds typically fed to horses.  It is interesting to note that the lowest NSC values are for soybean hulls, beet pulp, alfalfa and the highest NSC values are corn, oats and barley (COB) a food which is frequently fed to horses. So, it would be safe to say that grain based horse feeds will contain a higher NSC value than feeds based on beet pulp, soybean hulls and alfalfa meal.  For more information about NSC content of forages, please visit www.equi-analytical.com.

Average Sugar, Starch and Non-Structural Carbohydrate (NSC) Values of Selected Feedstuffs*.

Feedstuff Sugar Starch NSC
Oat Hay 16.0% 6.3% 22.1%
Barley Hay 14.9% 5.8% 20.4%
Alfalfa Hay 8.9% 2.5% 11.3%
Bermudagrass Hay 7.5% 6.1% 13.6%
Grass Hay 11.1% 2.9% 13.8%
Alfalfa Pellets 7.2% 2.3% 9.3%
Alfalfa Cubes 8.3% 2.0% 10.2%
Grass Pasture 10.3% 3.4% 12.1%
Rice Bran 6.2% 17.7% 21.2%
Oats 4.8% 44.4% 54.1%
Corn 3.7% 70.3% 73.3%
Barley 6.0% 53.7% 61.7%
Beet Pulp 10.7% 1.4% 12.3%
Wheat Bran 8.7% 23.0% 30.8%
Soybean Hulls 4.3% 1.9% 6.3%
Wheat Middlings 10.1% 26.2% 32.0%
Soybean Meal 14.3% 2.1% 16.2%
*Values are from Equi-Analytical Laboratories, Ithaca, NY, reported on dry matter basis.

If you have a problem horse and want to implement a low NSC value feeding program, it would first be necessary to estimate the NSC content of your pasture or hay.  However, having said that, sampling for the NSC content of your hay would not be practical if you do not have a supply that would last you several months.  If pasture is available for your problem horse, it may be necessary to remove him or reduce his grazing.   One surprising finding on current research concerning NSC levels of various hays was that alfalfa hay and alfalfa pellets had lower values than grass hay, so alfalfa hay may become the first choice for problematic horses (Geor, 2007).

Understanding nutrition and NSC values is difficult at best.  We can only strive to look to research to help us make proper, informed decisions regarding the safe nutrition of our horses.  One thing that I do know is that there is a great deal of research and people knowledgeable in the field of equine nutrition that can be accessed to help us with our equine nutrition program.


Equine Body Condition Score


There has been much discussion and many papers presented on Equine Metabolic Syndrome and how weight gain and obesity in horses should be avoided to prevent such ailments as insulin resistance, increased insulin and leptin blood levels and laminitis, but how many of us actually know the basics of equine body condition scoring?

We can look at our horse and say, “yep, he looks good”, or “oh my gosh, he’s fat!”, but can we actually put our horses in the score classification?  Below, is a handy chart that you can use to determine what body condition score your horse actually fits in.

Main areas to look at for body condition scoring

Score Description
1 POOR:Horse is extremely emaciated.  The backbone, ribs, hipbones, and tail-head project prominently.  Bone structure of the withers, shoulders, and neck easily noticeable.  No fatty tissues can be felt.
2 VERY THIN: Horse is emaciated.  Slight fat covering over vertebrae.  Backbone, ribs, tail-head, and hipbones are prominent.  Withers, shoulders, and neck structures are discernible.
3 THIN:Fat built up about halfway on vertebrae.  Slight fat layer can be felt over ribs, but ribs easily discernible.  The tail-head is evident, but individual vertebrae cannot be seen.  The hipbones cannot be seen, but withers, should, and neck are emphasized.
4 MODERATELY THIN: Negative crease along back.  Faint outline of ribs can be seen.  Fat can be felt along tail-head.  Hip bones cannot be seen.  Withers, neck, and shoulders not obviously thin.
5 MODERATE:Back is level.  Ribs can be felt, but not easily seen.  Fat around tail-head beginning to feel spongy.  Withers are rounded and shoulders and neck blend smoothly into the body.
6 MODERATELY FLESHY: May have a slight crease down the back.  Fat on the tail-head feels soft.  Fat over the ribs feels spongy.  Fat beginning to be deposited along the sides of the ithers, behind the shoulders, and along the neck.
7 FLESHY: A crease is seen down the back.  Individual ribs can be felt, but noticeably filling between ribs with fat.  Fat around tail-head is soft.  Noticeable fat deposited along the withers, behind the shoulders, and along the neck.
8 FAT:Crease down back is prominent.  Ribs difficult to feel due to fat in between.  Fat around tail-head very soft.  Area along withers filled with fat.  Area behind shoulders filled in flush with the barrel of the body.  Noticeable thickening of neck.  Fat deposited along the inner buttocks.
9 EXTREMELY FAT: Obvious crease down back.  Fat is in patches over rib area, with bulging fat over tail-head, withers, neck and behind shoulders.  Fat along inner buttocks may rub together.  Flank is filled in flush with the barrel of the body.

Body Condition Scores for Different Disciplines  according to The Henneke System of Body Scoring

The Henneke System of Body Condition Scoring also uses the above 1-9 scale to rate a horse’s overall body condition.  A horse with a body condition score of 1 is emaciated and in most cases in danger of starving to death while a horse with a body condition score of 9 is extremely obese.  According to the Henneke System, normal healthy horses have a body condition score from 4-7.

The following chart displays “normal” body condition scores for horses in a variety of working conditions:

Endurance 4-5
Eventing 4-5
Polo 4-5
Ranch 4-5
Open mare 4-6
Stallion (off season) 5-7
Standardbred racehorse 4-6
Thoroughbred racehorse 4-6
Hunter 5-7
Show Jumper 5-7
Breeding stallion 4-6
Dressage 5-7
Quarter Horse 5-7
Show hack 5-7
Pony 6-8
Pregnant mare 6-8