Question
Cola is my 21-year-old Thoroughbred gelding that weighs about 1,175 lb (533 kg). He is in light work. He is fed 6 lb (2.7 kg) of a high-fat feed per day and as much pasture as he chooses. He loses weight easily unless he is fed a high-fat feed. Unfortunately, this feed is expensive, and I'm not sure why he needs so much of such a high-fat content feed. Cola was maintained on approx. 8-10 lb (3.5-4.5 kg) per day of sweet feed before I bought him, but I opted away from it as I didn't think it as healthy, especially given his age and how he may be prone to Cushing's as he ages. Do you have any suggestions for an alternative diet that is affordable? I thought about stabilized rice bran, which is also expensive, and beet pulp. Would this be enough?
Answer
The probable explanation for why you are having to feed so much is because your horse is an aged Thoroughbred. It is quite common for Thoroughbreds to have higher metabolisms and need more calories in a day than most other breeds, especially those that have had racing careers. We have a few older Thoroughbreds here at the Kentucky Equine Research farm and have done some feeding studies on them, one of which I think is pertinent to your situation, and I will get to that in a minute.
First, you do not need to be concerned about a feed with starch causing Cushing’s. If a horse is going to develop the tumor on the pituitary gland, which is the basis of Cushing’s disease, there is not really anything you can do to avoid it. Certainly, whether or not starch is included in his diet will not be a factor. What the low-starch feed does once a tumor has developed is to maintain a steady blood sugar level and not aggravate the condition. Yes, a low-starch diet is recommended for a horse with Cushing’s, but a horse that doesn’t have Cushing’s doesn’t necessarily need a low-starch diet.
This leads me to the possibility of feeding an aged Thoroughbred a moderate amount of starch. Normal horses are very tolerant of having starch in their diets, especially Thoroughbreds. In the research study I mentioned earlier, we fed our geldings either a moderate-starch feed (a typical sweet feed) or a high-fat, high-fiber feed, and looked at insulin sensitivity with highly specialized tests. We found that when horses were fed the high-fat, high-fiber feed they tended to become more insulin resistant than when they had some starch in the diet, as if having starch in the diet kept their insulin metabolism primed for handling rises in blood glucose. This is why I don’t think you really need to avoid starch for your horse; he may do better trying to get some of his calories from starch. Some horses seem to be more efficient at getting the calories out of the starch than the high-fiber ingredients used in horse feeds.
High-fat, high-fiber feeds are expensive to manufacture, which is why it is costing you so much to feed your horse. I really think he would do just fine on a moderately priced feed with a moderate amount of starch. Even a good-quality pelleted feed may work as well as anything. If you do that, then supplementing with soaked beet pulp will make more sense in the diet and cut down on the cost a little. You can always add oil to bump up the calorie content as well. Just make sure you don’t feed less than the minimum recommended amount by the manufacturer so that you don’t short your horse on the nutrients supplied to balance the feed. I don’t think you will ever get away with feeding much less in total than you are, so your savings will have to come with your feed choice.
