The equine-nutrition buzzword ?omega? can influence your choice in feeds and supplements. What you may not realize, though, is which omega your horse needs and which you're truly getting.
Omega-3 and omega-6 fatty acids are important in the equine diet because they?re the only forms of fat the horse cannot synthesize, or make, in his body. That means they must be present in the horse's diet in order for the horse to benefit from them.
A horse who is deficient in his intake of these essential fatty acids will likely have a dry coat, skin and hooves. Internally, he'll be battling impaired immunity, an increased tendency for allergies or exaggerated immune responses, low-sperm counts and ?stiffer? red blood cells that don't fit through the tiny capillaries as easily as they should. there's also some scientific evidence that omega-3s can protect cartilage from damage, which means joint health.
Fish-oil-supplemented stallions have higher sperm counts and better quality of frozen sperm. Broodmares given fish oil have higher omega-3s in their milk and higher IgG in colostrum.
Horses supplemented with fish omega-3 have lower cholesterol than horses given corn oil, which is not to say that horses have to be concerned about high-cholesterol problems, like humans. However, it's an interesting fact nonetheless.
Cells from horses supplemented with flaxseed have a less violent reaction to endotoxins. Endotoxins result from a breakdown of bacteria and cause gastro-intestinal disease and even airway problems. Endotoxemia is a leading cause of equine death, through colic and septicemia in foals.
Both flaxseed and fish-oil supplementation increase the skin?s reaction to an injected irritant, but flaxseed supplementation may decrease allergic responses. One fish-oil study found lower heart rates and lower hematocrits during exercise in supplemented horses.
Note: The hematocrit is a blood test that measures the volume of red blood cells to plasma. A high hematocrit, which is an excess of red blood cells, may be associated with increased stress or with dehydration. A low hematocrit result may be associated with anemia.
In grass, the horse's natural diet, omega-3 is present in the form of alpha-linolenic acid, while omega-6 is alpha-linoleic acid. Once inside the horse's body, omega-3 is converted DHA (docosahexaenoic acid) and EPA (eicosapentaenoic acid), which are fats that can be metabolized into anti-inflammatory compounds that protect the immune system cells and have antioxidant effects. Fish oil is high in DHA and EPA.
Omega-6 is converted to arachidonic acid and two inflammatory prostaglandins, all of which are also important to a strong immune response. These fatty acids also become incorporated in the hair, hoof, skin and the membranes of cells, including red blood cells.
The omega-3 fatty acids are a hot topic in human medicine where it has been documented that higher intake of omega-3s can help insulin resistance, hypertension, elevated cholesterol or triglycerides, and heart disease. For people, a ratio of 5:1 for omega-6:omega-3 has been proposed. Fish oil, with high levels of DHA and EPA, is usually recommended to these people.
The suggested omega-6:omega-3 ratio for humans comes at least in part from analyzing diets that are known to be associated with low risk of obesity and heart disease, like the Mediterranean diet. However, people are omnivores while horses are herbivores. So, for horses, the logical place to start looking at ratios would be with the horse's natural diet, which is grass.
The target for horses is the same as the normal ratio found in grass, which is from 1:3 to 1:6, omega-6:omega-3. This is the reverse of the most frequently recommended intake for people.
Interestingly, tree bark and tree buds ? virtually any live plant that horses may turn to during winter or drought conditions ? are also high in omega-3 compared to omega-6.
[IMGCAP(4)]Unfortunately for horse owners, omega-3 fatty acids are fragile and lost when grass is cut, dried and stored as hay. The ratio is between 14:1 and 10:1 omega-6:omega-3 in dried hay.
Concentrates, aka grains, run about 16:1 omega-6:omega-3. All vegetable oils, except flaxseed oil, are also high in omega-6 compared to omega-3. Therefore, if we compare the diet of the stalled horse to one on pasture, clearly the stalled horse's diet is comes up shorter on omega-3 fatty acids.
So, it's easy to see that there are a lot of good reasons to supplement omega-3. The question is how best to do it.
Our Field Trial.
When you realize the huge difference in omega-3 intake between horses eating a fresh diet and those on hay or hay and grain, there's no question that your omega supplement needs to be high omega-3.
The logical choice in vegetable sources is flaxseed. The fatty acids in ground flaxseed remain stable for at least six months, although you should avoid storing it under conditions of high heat.
A new option on the sales floor is fish oil for horses. Fish oil contains DHA and EPA rather than the alpha-linolenic acid present in plants. Studies have confirmed that feeding fish oil versus flaxseed does lead to higher concentrations of DHA and EPA. However, flaxseed has never been compared to fish oil side-by-side in a research setting in terms of coat/hoof health, reproductive effects or athletic performance.
[IMGCAP(5)]Our field trial evaluated palatability, coat conditioning effects and heart rate response to a three-minute mile at the trot or pace in Standardbreds in training after 30 days of supplementation.
Post-exercise heart rates dropped similarly in flaxseed, fish-oil and unsupplemented horses, probably as a result of improved fitness and conditioning.
Note: It should also be pointed out that the study we mentioned on page 3 that found an effect on heart rate in fish-oil supplemented horses fed 5.7 ounces per day to a 500 kg horse, a much higher dose than recommended on these products.
Both fish oil and flaxseed improved coat quality, with the minimum effective dose being 20 grams of omegas/day. We have conducted multiple field trials in the past on dry flaxseed products (see sidebar on page 4), but this time we concentrated on more recent developments in omega supplementation, including a liquid flaxseed product and fish oil.
Kentucky Karron Oil, ?Nutramax?s Welactin, and Kauffman?s Fish Oil gave us excellent results, and we were pleased that they?re high omega-3 supplements. But flaxseed is less expensive than fish oil, which gives Karron Oil our top choice and Best Buy.
Editor's Note: Unfortunately, not long after we completed this trial, the makers of Kentucky Karron Oil determined that the cost of shipping the product overseas to the United States was too high, and they stopped sending it to the USA.
Article by Eleanor Kellon, VMD, our Veterinary Editor.