Most of us have been around horses for over 2 decades and we remember the times when the base of every equine diet was hay, oats and flax. To that, we added a variety of other real food such as apples, carrots, bananas, corn, barley, and the occasional bran mash. So what happened and why did we move to a diet of processed feed made with left overs of human food manufacturing and what are the effects on our horses?
In an article by Kentucky Equine Research, a commercial feed manufacture of processed equine feed, the following was stated: “Processing is performed in order to improve the digestibility of a feedstuff, to extend the shelf life of a product, or to make use of some by-products of the human food industry such as wheat middlings, soybean meal and hulls, rice bran, and beet pulp.” Yet it also states that “Pelleting increases feed digestibility less than 5% in horses with normal teeth.” ~ By Associated Feed · January 17, 2001.
In an article by R.J. Coleman, Associate Professor – Equine Extension of the University of Kentucky, ‘Grain processing for horses: does it pay?’, Coleman found evidence to the contrary and concluded that “The use of rolled, crimped or steam flaked grain will continue in feeding horses. The reason for its use will not reflect advantages in nutrient availability, but will be due to marketing and production of commercial feeds.”
He stated that ‘there will be the continued concern by horse owners when whole grains, particularly oats, are included in the concentrate mixture, because hulls will be visible in the manure. It is important to remember that most of these visible hulls are just that, only hulls which are poorly digested. Even with rolled or crimped oats, hulls are in the manure; however, they are not easily distinguished from the rest of the manure.”
What happens when whole grain is processed? We now know that there is no real benefit on digestibility in feeding processed vs. unprocessed grain. I won’t argue that there is a benefit to feed manufacturers in utilizing ‘some by-products’ of the human food manufacturing’. After all, oats are a lot more expensive than soy hulls, beet pulp, and wheat middlings. There is also the benefit of increased shelf life. We have all seen feed weevils in our bags of oats in the hot summer months. While they are completely harmless to horses, they are surely an eye sore. However, if you keep them dry, they will hardly ever mold. Mold can have very negative effects on a horse and feed stuff with molasses molds easily.
What else happens when when grain is processed? Other than starch and fiber, it loses all it’s nutritional value. Grinding oats will destroy the germ of the oat which contains the oils, vitamins, minerals and antioxidants. Cooking feed stuff, which happens in the process of pelleting, destroys all vitamins and most minerals. It can increase glycemic load (GL) – post meal insulin generation, which increases the chances of behavioral problems, OCD’s (bone lesions), as well as insulin resistance. In fact the American Association Of Diabetes states that food processing increases GL and recommends to replace them with whole foods.
What about the vitamins? Commercially processed grain is fortified with synthetic vitamins and minerals as the food processing destroys them. Horses synthesize most of their own vitamins, with the exception of vitamin, E and A. The germ of a whole grain contains vitamin E and so does pasture. Vitamin A can be toxic, as excesses will accumulate in the liver. Toxicity can cause bone fragility and therefore lead to orthopedic disease in growing horses as well as areas of abnormal bone growth. It can also contribute to itching, peeling skin and birth defects. The symptoms of bone disease include swelling, as well as pain and fractures. Fresh pasture and alflafa hay contain an abundance of carotenoids, the precursor of vitamin A. In fact, According to figures published by the National Research Council, alfalfa hay contains almost 25,000 IU of vitamin A per kg, which exceeds the total daily requirement of vitamin A for all classes of horses. Horses also receive roughly 700% of their daily iron requirement in hay and pasture, and iron overload can lead to metabolic disease, laminitis, arthritis, heart failure and liver toxicity. Iron supplementation of equine feeds can only have negative effects on the horse and is completely senseless. Given the increasing numbers of thoroughbred horses with metabolic disease, while they are not genetically predisposed, withdrawing iron fortified feed from their diet should be given consideration.
Horses synthesize vitamin C on their own by converting glucose to vitamin C. “Supplementing a healthy horse with vitamin C is pointless” (Kentucky Equine Research). In fact, a recent article in the American Journal of Clinical Nutrition (Vol. 87, No. 1, 142-149) reveals that supplementation with vitamin C ascorbate devastates the muscle, causing impairment in mitochondrial function, loss of endurance, and inhibition of the body’s own antioxidant enzymes superoxide dimutase (SOD) and glutathione peroxide. It was shown that supplementation of racing greyhound dogs with 1g vitamin C/day for 4 weeks significantly slowed their speed. Then why are all commercially processed grains fortified with ascorbic acid, the synthetic form of vitamin C or any vitamins at all? And why are they more expensive than oats, when they were designed to save horsemen money and the ingredients are much cheaper than oats?
The possible benefits of the modern equine feed industry are the utilization of by-products of human food manufacturing, extended shelf life, and less than 5% increased feed digestibility in horses with normal teeth. So I will agree with R.J. Coleman in that ‘the reason for its use will not reflect advantages in nutrient availability, but will be due to marketing and production of commercial feeds’. The only natural and beneficial diet for our horses is excellent hay and pasture with the addition of small amounts of whole foods. For horses with compromised dentition, feed can be soaked.