Question

I have a 17-year-old off-track Thoroughbred gelding that is running very thin, and I am considering a change to his diet. He is getting canola oil with every feed. I thought about switching to corn oil but would like to know how corn oil stacks up against canola oil. Which is better? He is on a prescription NSAID (firocoxib) for arthritis, and I would like something to help with ulcers, just in case. Please help.

Answer

Before going into detail about the differences in oils, there are a few basic nutritional guidelines for weight gain to consider, some or all of which you might have already implemented:

• Because forage makes up a significant part of any horse’s diet, a thin horse should be offered high-quality forage, whether that is pasture or a preserved forage such as hay. Alfalfa or an alfalfa-grass blend hay might be appropriate for this horse if or when he does not have access to pasture. If that is not available, high-quality grass hay supplemented with alfalfa pellets or alfalfa cubes might be warranted. The horse should be given at least 1.5% of his ideal body weight in forage daily. If, for example, your horse should weigh 1,200 lb (545 kg) when in moderate body condition, he should be offered at least 18 lb (8.2 kg) of forage daily. For gastrointestinal health, he should never go more than two or three hours without forage.
• In addition to forage, he should be given a high-quality concentrate fed according to the manufacturer’s recommendations. For weight gain, you may find that you must feed at the upper end of those recommendations. Keep meal size small so the gastrointestinal tract has ample time to process each serving. A general guideline is to feed no more than 5 lb (2.3 kg) of concentrate in a single meal. Some horses gain weight well on feeds that derive their energy from multiple energy sources, including starch (cereal grains), fermentable fiber (beet pulp, soy hulls), and fat (vegetable oil, rice bran). Many senior feeds feature these energy sources.
• With specific respect to nutritional management, does your gelding have a quiet place to consume his concentrate meals and hay, or is he fed in a group? Competition for food can be stressful for horses. If they are low on the social hierarchy, as some aged horses are, they may refuse to fight for feed and forage. Consider feeding him individually if this is the case with your gelding.
• Schedule a comprehensive medical exam, including a thorough dental evaluation and a fecal egg count for parasites. Unthriftiness in aged horses can often be traced to dental problems, such as loose or wobbly teeth, sharp points, or uneven biting surfaces.

With those general principles out of the way, let’s address your questions about oil. As more research is conducted, scientists are uncovering new information about what types of fatty acids are most important and how they influence the body in various ways. Researchers know that the type of fat matters but are still unclear on optimal levels.

Regarding simple weight gain goals, all oils are the same as they are almost entirely fat and contain the same concentration of calories. Dry fats, on the other hand, can vary considerably in percentage of fat.

When asking which fat is “better,” we assume you are referring to omega fatty acid profiles of different oils? If that is the question, while corn oil is an inexpensive, effective product for calories, it is extremely high in omega-6 fatty acids, which are generally considered pro-inflammatory. Alternatively, canola and soybean oil are also inexpensive but have a moderate omega-3 to omega-6 (O3:O6) ratio. Flax is another, though more expensive, option. Omega ratios for common oils include: corn oil (1:87), soybean oil (1:7), canola oil (1:3), flax oil (4:1), and fish oil (6:1). Choose a cost-effective oil that minimizes adding high levels of omega-6 fatty acids.

Regardless of the oil used for calories, consider adding in 1-2 oz of EO-3, a high-quality omega-3 fatty acid supplement. It provides the long-chain fatty acids EPA and DHA rather than the short-chain fatty acid ALA. Researchers at Kentucky Equine Research proved horses are not able to effectively convert ALA found in flax to long-chain fatty acids. The long-chain fatty acids EPA and DHA have greater anti-inflammatory and immunomodulatory properties based on the eicosanoids they produce. (Learn more about fatty acids.) As such, flax oil and other vegetable oils do not have the same anti-inflammatory benefits as EO-3.

Although EO-3 supplies the same concentration of calories as other oils, it is cost-prohibitive to use it as a source of calories. Replacing a portion of the oil with EO-3, however, will improve the dietary ratio of omega-3 and omega-6 fatty acids. One recommendation for both weight gain as well as anti-inflammatory benefits would be to provide flax or canola oil as a calorie source (4-8 oz/day) and supplement with 1-2 oz/day of EO-3 as a source of EPA and DHA.

Regarding ulcers, the main reason corn oil has been historically recommended as an appropriate fat source is based on a single published study from 20 years ago that reported reduced gastric acid output when four horses were fed 45 mL of corn oil. The mechanism of action was believed to be due to prostaglandin production, but it was the only research available to horse owners for years. Kentucky Equine Research recently published a paper evaluating the role of different supplementary fatty acids (including a corn-flax treatment) on the prevalence of ulcers in training Thoroughbreds. While researchers still have more to learn about the use of specific fatty acids in diets, horses glean the most benefit from direct intake of longer-chain fatty acids, including reduced incidence of ulcers when fed an oil containing three specific fatty acids: GLA, EPA, and DHA. The result of this research is ReSolvin EQ, a revolutionary oil designed to support gastric health one meal at a time through strategic supplementation of the polyunsaturated fatty acids mentioned above. Should you choose to feed ReSolvin EQ, there is no need for EO-3.

As a final note, horses fed high-fat diets should be offered a supplemental source of natural vitamin E, especially if the main forage source is a preserved forage such as hay. Choose Nano-E for superior bioavailability.