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Equine Nutritionist Farm Call: Three Horses, Three ProblemsBy Kentucky Equine Research Staff · February 18, 2016

In this digital age, equine nutritionists spend plenty of hours in front of computer monitors, flanked by volumes of support material, conscientiously answering the queries of horse owners. Though technology has widened the scope of their helpfulness, most nutritionists will agree that, when possible, it is best to visit farms for a firsthand look at the horses and management practices in place.

Recently, a nutrition advisor from Kentucky Equine Research (KER) helped a horse owner with her three off-the-track Thoroughbreds. A succinct description of each horse using information provided by the owner follows.

  • Edgar is a retired event horse that stands about 17 hands (172 cm) and weighs 1,050 lb (475 kg). He just turned 21 years old. He is a “low-level” hard keeper and does almost no regular work. He eats 6 lb (2.7 kg) of textured feed two times a day, and he receives two 5-lb (2.3-kg) helpings of hay each day as well. He has no access to pasture, though he has plenty of time in a paddock. He has begun to lose weight. Even before this perceptible weight loss, he needed to gain weight. When he was competing, he excelled on a product formulated by KER that was chock-full of fiber and other alternate energy sources. Though he is an excellent eater, he eats slowly.
  • Faye is a seven-year-old mare that stands about 16.3 hands (170 cm). She trained on the track but never raced. Faye was recently adopted through a rescue organization, and she’s in OK weight, not too skinny, and probably weighs about 1,000 lb (450 kg). Like Edgar, she receives about 6 lb (2.7 kg) of grain two times a day and two large meals of hay, 5 lb (2.3 kg) each. She too has no access to fresh pasture. She lives outside with a run-in shed.
  • Gretel is a six-year-old mare, and she was retrieved from a rescue at the same time Faye was. She is also about 16.3 hands (170 cm), but she is noticeably underweight, probably 900 lb (410 kg). She has rainrot and other various skin funk. Her management regime is similar to Faye’s as far as quantity of feed and forage offered. She lives with Faye and is a slow eater, sometimes frustratingly so.

Other notes of interest provided by the owner:

  • All three have been dewormed and vaccinated recently. All will have their teeth assessed in the next few weeks.
  • The owner believes the horses should be getting more hay, but it’s hard for her to convince the caretakers that this is so, as many of the other horses do fine on similar quantities of hay.
  • The feed currently in use is a low-end pellet (12% protein, 6% fat, 23% fiber). In the past, the owner has used a custom-blended textured feed with oats, corn, beet pulp, and oil (12% protein, 8% fat, 16% fiber).

The primary concern of the horse owner centered on weight gain and how best to economically achieve this in these three Thoroughbreds. While the nutritionist addressed this concern doing the site visit, other topics were mentioned, all with an eye on boosting the health of these three nice individuals. Comments from Catherine Whitehouse, M.S., the advisor:

Three things strike me immediately when I assess the diets of these horses: (1) the limited amount of hay offered, (2) the high ratio of concentrate feed to forage, and (3) the need for targeted supplementation for horses with specific problems.

Evaluation of the hay revealed a mid-quality grass hay that was free from any dust, mold, or debris. The types of grasses were not readily identifiable, as timothy or orchardgrass might have been, but the hay was well-cured and green. The horse owner is correct in her assumption that offering her horses more of this forage will undoubtedly benefit them. In fact, if possible, all should have free-choice access to hay, at least until they have reached the goal of moderate body condition. Allowing free-choice access will bring back into alignment the skewed concentrate to forage ratio.

If free-choice hay is not an option, the owner should insist upon at least 10 lb (4.5 kg) per feeding for each horse, adjusting up or down to avoid wastage but still supplying as much as they will consume. A flake of this hay weighed about 2.5 lb (1 kg), so the owner should feed about four generous flakes at each feeding to each horse.

A change in concentrated feed is probably in order. Choosing one that resembles the custom-blended textured feed described by the owner, in both ingredients and nutrient composition, seems the most logical direction to go at this point. Look for a feed with 8-10% fat and fermentable fiber sources, such as beet pulp and soy hulls. Feeds with multiple energy sources (starch, fat, fermentable fiber) seem to be particularly useful for horses with weight issues.

Feeding a high-fat diet allows the owner to offer a smaller amount of feed but still provide the appropriate amount of calories needed for weight gain. According to the amount of weight these horses need to gain, offering them between 8-12 lb (3.6-5.5 kg) of concentrate feed may be needed initially to boost their condition, though feed amounts vary greatly between products and individuals.

Based on the breed and height of your horses, their target body weights are in the range of 1,250–1,350 lb (570-615 kg). Weight gain is going to take place over several months, even with the provision of appropriate calories. Monitoring their progress is very useful as it allows small dietary adjustments to be made in a timely manner. Assessing body condition, assigning and recording a condition score, and weighing them (using a weight tape or an electronic scale, if possible) at least once every two weeks allows the owner to track gains in relation to goals.

In addition to offering more feed, giving smaller meals more often throughout the day can improve weight gain. Small meals do not overwhelm the digestive tract, particularly the stomach and small intestine, allowing the horse to fully use the nonstructural carbohydrates and fats in the feed. I recommend offering 3-4 lb (1.4-1.8 kg) of feed per meal and no more than 5 lb (2.3 kg) per meal; keep meals at least five hours apart.

Another way to boost caloric density of a ration is to supplement with a high-fat feedstuff such as stabilized rice bran or top-dress with vegetable oil (soybean or canola). Adding stabilized rice bran (1-2 lb; 0.45-0.9 kg) or oil (1-2 cups; 250-500 ml) can help add condition to most horses and does not significantly increase the amount of feed offered. Fat should be added slowly to the horse’s diet to allow the digestive tract to become familiar with it; shoot for a gradual increase over a week to 10 days.


Maintaining digestive health is as important as providing enough digestible calories for weight gain.


Maintaining digestive health is as important as providing enough digestible calories for weight gain. Complementing a weight-gain diet with a digestive supplement aids in maintaining gastrointestinal health, even when large amounts of concentrates are needed. RiteTrac, available in the U.S. and other markets, provides complete digestive support of the foregut and hindgut. Australian horse owners should look for other research-proven digestive supplements.

RiteTrac contains EquiShure, a time-released hindgut buffer, which is the only product available that can deliver an active buffer to the hindgut. EquiShure supplementation helps to keep the hindgut microbial population stable, key to maximizing fiber digestibility. The slow eaters in the herd, namely Edgar and Gretel, might experience an increased appetite with these products, as oftentimes horses eat slow because of stomach or hindgut discomfort.

Your six year-old mare is likely suffering from chronic rainrot due to her low body weight and compromised immunity. Daily supplementation of marine-derived omega-3 fatty acids (DHA and EPA), like those found in EO•3, can strengthen the horse’s immune system as well as improve the health of the skin and its defenses against the organisms that cause rainrot.

Another important immune-building nutrient is vitamin E, especially for horses that do not have access to fresh green grass and those maintained on hay-only diets. Not all vitamin E products are created equally, as natural-source vitamin E has proven to be significantly more bioavailable to the horse than synthetic forms. Nano•E is a water-soluble form of natural-source vitamin E that rapidly improves the vitamin E status of the horse.