Counting Calories and Cutting Carbs

Tuesday March 15 2011

I talked about training horses in the last series, now let's talk about the equine diet. Here's a reprint of an article I wrote for Trail Blazer in 2006 on that subject.


Counting Calories and Cutting Carbs - The Round Table Discussion

Humans may shudder at the thought of worrying about calories, carbohydrates and fat in their diets. But what about horses? Do they need extra carbohydrates in the diet? More fat or more calories? Or less?

We took up the weighty subject of equine diets at a virtual round-table discussion with a trio of experts. Dr Joe Pagan is the founder and president of Kentucky Equine Research in Versailles, Kentucky. KER conducts detailed nutrition and exercise physiology studies, and serves as a consultant to feed manufacturers worldwide. Dr Melyni Worth, Ph.D. P.A.S., of Foxden Equine Nutrition and Therapy in Virginia, holds an International Trainers License from the European Union, and has trained horses and riders for 28 years. In addition, corresponding with her Ph. D. in Equine Nutrition and Exercise Physiology, she works as a consultant and writer. Dr Juliet Getty holds a Ph.D. in Animal Nutrition, and has been in the field for 20 years, including teaching at the University of North Texas. Since she started Getty Equine Nutrition 2 years ago in Texas, her nutritional consulting services have expanded around the globe – from backyard horse owners to large breeding farms.



1) We began with the following quote: “High fat/low carbohydrate diets are the most important advancement in equine nutrition since the advent of commercial diets.” What is your opinion of this statement?

JOE PAGAN: I’d say that’s probably a reasonable statement, though I might modify it by saying “High fat, high fermentable fiber and low starch” diet. By fermentable fiber, I mean what you’re adding to your feed, such as beet pulp and soy hulls. The research we’ve done in the last 20 years emphasizes alternate energy source diets, or alternate lower starch diet – not necessarily an emphasis on high fat, but on lower starch content.

MELYNI WORTH: OK, sure, low carbohydrates being the key. Or, maybe I’d say high fiber/low carbohydrate diet. And to be even more specific, a high fiber/low simple carbohydrate diet. It’s the simple carbs – those that come from grains - that can cause problems. These are digested in the stomach and small intestines into sugar, which moves into the blood. Too much over a long period can lead to problems. The complex carbs – we call this fiber – are digested in the hind gut, and this is what the horse evolved to survive on.

JULIET GETTY: I wholeheartedly agree with this statement.  Horses’ digestive systems are not designed for large amounts of starch.  Grains, such as oats, corn, barley, wheat, rice, etc., are highly concentrated in “nonstructural carbohydrates” (NSC) which include starch and sugars.  Too much starch has many negative consequences. 


2) Will this diet benefit all horses, or just hard-working horses?

JOE PAGAN: Lower starch diets are healthy for all classes of horses. You don’t risk starch overload, which could lead to colic from fermenting too fast in the hind gut. A high starch diet produces high levels of glucose, which can lead to insulin resistance, contribute to muscle disorders such as tying up, and cause behavioral issues such as excitability. The lower starch diet is safer because you don’t run these risks, and it’s more natural for the horse. Feeding high fat to, for example, endurance horses would be for more efficient energy use. By adapting to a higher fat diet, it will teach the muscles to burn fat, i.e. condition the horse to switch to fat-burning quicker. Feeding fat, along with long slow exercise, will condition the muscles to do this.

MELYNI WORTH: Absolutely; a higher fiber, low carb diet is good for all horses. The horse was born to survive off forage. In the old days when we started using horses for hard work, we started adding grain to their diets to meet their extra energy needs. In the 1960’s, the number of working horses plummeted, but we kept the mindset of grain feeding. Unless the horse is working hard and needs these extra simple carbs, the muscles can get to where they don’t respond to insulin, and this can lead to problems similar to Type II diabetes.

JULIET GETTY: The best way to answer this question is to look at what too much starch (from grain) and sugar (from sweet feeds) can do to a horse’s system. Starch and sugar 1) raise blood glucose levels, which can produce highs and lows in energy levels; 2) cause an increase in insulin levels which can lead to insulin resistance and Metabolic Syndrome. Elevated insulin is also a problem with a horse suffering from Cushings Syndrome; 3) increase acid production in the stomach and should therefore be avoided in horses who have or have had ulcers; 4) when fed in large enough quantities can move past the small intestine into the hind gut,  where they can be fermented by the bacterial flora that naturally live there.  Such fermentation can result in acid production, thereby killing these good bacteria.  The release of endotoxins result and can lead to laminitis; 5) when fed to foals and growing horses can increase the incidence of Developmental Orthopedic Diseases (DOD). So, this low starch diet is really best for all horses.


3) How are energy shortfalls met?

JOE PAGAN: Does your horse need the extra energy? If he is not working hard or in heavy training, his energy requirements could be met with just a forage-based diet. On the other hand, lactating mares, for example, will have higher energy requirements, and forage alone will not meet their energy needs. For horses that need the extra energy, it shouldn’t be either fat or starch; it should come from multiple energy sources.

MELYNI WORTH: If the horse does have extra energy needs, meet these with fat, not more carbs. Feeding lower carbs is just better for horses in general. They do need carbs, but not too many; fat, but not too much. More is not necessarily better – too much of any one thing is not good. It should be a mixture of all, but less sugar. Try to move away from sugar.

JULIET GETTY: A safer energy source rather than starch is fat, which is very well tolerated. Energy (additional calories) can easily be provided by adding feed sources that have low NSC levels. For those horses that are worked intensely, extra calories can be added by providing beet pulp, stabilized flaxseed meal, and stabilized rice bran.  Flaxseed oil and canola oil are also worth adding if even more energy is needed.   


4) Which feeds do you recommend, to get the recommended amount of fiber, carbs, fats, etc.?

JOE PAGAN: For high fermentable fiber, add beet pulp or soy hulls. For added fat, we recommend vegetable oils. We are beginning to steer away from corn oil because of its ratio of Omega 6 to Omega 3 fatty acids. Simplistically, omega 6’s are not good. Soy oil has a lower omega 6 to 3 ratio, and flax oil actually has an inverse ratio. Some commercial feeds contain about 10% high fat and fermentable fiber, with the beet pulp already added. This mixture reduces the high carbohydrates, but the overall energy needs are met.

MELYNI WORTH: If you do add carbs, I recommend whole or rolled oats – the safest feed there is. Beet pulp and soy hulls are fiber sources if the horse doesn’t get enough hay, or if you want something to add your vitamin and mineral mix to. The best fat to feed is the most unrefined fat source - no animal fat, because horses weren’t made to digest animal products. Feed vegetable fat, such as (in my order of preference) 1) whole flax seed, 2) whole roast soybeans (cooked, never raw), or 3) black oil sunflower seeds. You can feed the flax or sunflower seeds raw. If you do grind the flax seeds, feed them right away; don’t let them sit around because they can mold. I don’t feed peanuts because of the mold factor. If you can’t get any of these three fat sources, you can use vegetable oils, such as corn or canola, as a last choice. For adding fiber to the diet, hay if possible. Hay, hay, and more hay. The best hay to feed is the best feed to give. Hay is best, and of that, clean, well-made grass hay is best – any cutting, but no mold. Some alfalfa is OK, but too much is bad because it’s high in protein and calcium, and it’s too hot. If you do feed alfalfa, feed no more than 20% of the daily diet.

JULIET GETTY: If someone is wanting a complete ration, look for one that has 12 to 14 percent protein, at least 4% fat, and at least 18% fiber.  Add it to the diet to provide additional calories to meet workload needs.  If a horse is not being exercised, feed 100% hay, with a small amount of a complete ration or even beet pulp or alfalfa pellets as a carrier to add any supplements. Grain (oats, corn, barley, etc.) should only be fed in small amounts – no more than 3 lbs per day – and only to adult horses that have additional energy needs due to an increased workload.   Oats are digested the most efficiently.  Corn, in my opinion, is to be avoided since it is more likely to end up in the hind gut undigested. 


5) How is it best to feed fat?

JOE PAGAN: Muscles won’t automatically start burning fat as soon as you start feeding it; they must be trained to do so. One study showed it takes 4 weeks for the body to adapt; another study showed 5 weeks. In an endurance horse, for example, it won’t help to start ‘fat-loading’ a few days before the event. Feeding fat and training is the only way to utilize this diet for efficient energy use.

MELYNI WORTH: Since horses were born to handle forage, don’t worry about switching hay diets. However, any other diet change should be introduced gradually. To begin adding fat to the diet, start with adding just 2 ounces of (for example) flax seed the first week; increase it to 3 ounces the next week, 4 the next, etc. Sometimes it’s hard to get a cup of oil down a horse because of the unplatability, which is another reason to recommend the seeds.

JULIET GETTY: Horses have a high tolerance for added fat.  Oil can be added up to 2 cups per day, if necessary.  However, most horses do not like oily feed, so I prefer to add a high fat top dressing to the diet such as flaxseed meal, stabilized rice bran (make sure it has added calcium), or commercial preparations that are made from these.  Kent Feeds and ADM Alliance offers a such high fat top dressings, for example.


6) What are the drawbacks?

JOE PAGAN: Feeding too much fat inhibits glycogen storage. Another drawback can be feeding too much fat too fast, which can cause scouring. Get them used to ½ to 1 cup a day if you are using oil.

MELYNI WORTH: If you overfeed fat, you can get diarrhea. It can also interfere with mineral digestion, so add a high quality vitamin/mineral supplement, particularly with magnesium. I think the true major drawback of feeding high fat is feeding it when you don’t need it! Again, it’s often this mindset that we have to add grain to a horse’s diet. If he doesn’t need the extra calories or energy, hay should meet all his requirements. I say, hay, hay, and more hay! Get the horse back to the way he was born to be.

JULIET GETTY: None.  I have hundreds of clients that I have switched to this type of feeding plan and their horses are blossoming into the body they were meant to have.  The only problem with this diet is convincing those who have been feeding oats and sweet feeds for years that a low starch diet is more in tune with a horse’s natural digestive process.  Old habits die hard. 


Dr Joe Pagan’s website is www.ker.com;
Dr Melyni Worth’s website is www.foxdenequine.com/;
Dr Getty’s website is www.gettyequinenutrition.com