Page 112 - November_2023

VETERINARY VIEWS
there is a caution on using omega-3 fatty acid supplementation in individuals with a compromised immune system.
Fatty acids are synthesized to substances called eicosanoids, which act as mediators
of inflammation and blood coagulation. Eicosanoids are short lived in their activity and are eventually metabolized by enzymes. But if the rate of synthesis exceeds metabolism, then excess eicosanoids can exert deleterious effects. Omega-6 fatty acids are blamed for an increase in inflammatory responses. However, omega-6 is responsible for fatty acid benefits to skin health, as an example.
Typical fat supplements, such as corn
oil and soy oil are rich in omega-6 fatty acids. Linoleic acid (omega 6) is converted
in the body to gamma-linoleic acid (GLA), also known as polyunsaturated fatty
acids, which can either be converted to arachidonic acid, which is responsible for inflammatory effects, or it can convert to dihomo gamma-linoleic acid (DGLA), which prevents inflammatory effects. Adequate amounts of nutrients, such as magnesium, zinc, and B vitamins, promote conversion
of omega-6 fatty acids to DGLA. This
is a good argument for rations with total balanced nutrition as opposed to focusing on one ingredient or ‘magic’ nutrient. Adding flax seed to an unbalanced or nutritionally deficient diet may not be of much benefit but including it as part of a well-balanced diet may have positive consequences for the horse.
Studies have shown that breeding
stallions receiving fat supplementation as docosahexaenoic acid (DHA) have an increase in sperm concentration and motility, along with improved percentages of morphologically normal spermatozoa.
FAT FOR REPRODUCTION AND GROWTH
Grain/sugar/starch intake can be minimized by supplementing with fat, including to the pregnant or lactating mare. As a calorie source, fat supplementation allows a nursing mare to consume sufficient calories for the demands of lactation without having to consume large volumes of grain. Research has also shown that mammary tissue preferentially utilizes dietary fat – there is an increase in milk fat in mares fed 5% added fat in the diet. This results in
an early growth advantage to their foals. Mares in the study ate more calories without gaining weight, indicating that fat calories are utilized in the milk.
Fat supplementation in growing foals provides essential fatty acids as well as replacing some starch and sugar calories with fat and fiber calories. The notable proposed benefit of this alteration in calorie source is a reduction in the incidence of developmental orthopedic disease, although research has been unable to support that consistently. Addition of fat to growing horse diets must also consider alterations in the nutrient to calorie ratio of the diet. Adding fat without reformulating to provide adequate protein, vitamins and minerals can lead to fat foals without proper nutrients to support optimal lean tissue growth and development.
As to fatty acid effects on breeding stallions, according to research on the effects
on semen quality, ALA didn’t elicit a response, but DHA did increase motility of thawed, previously frozen semen. There is a reported 1.8-fold increase in sperm concentration and motility characteristics following 48 hours
of cooled storage, and other studies reported improved percentage of morphologically normal spermatozoa in the fat-supplemented stallions. Flaxseed did not produce the same results as the marine-based omega-3’s.
FAT FOR BEHAVIORAL MODIFICATION
With regards to behavioral modification by dietary supplementation of fat, have realistic expectations. Horses fed fat-supplemented diets have been reported to show less ‘spontaneous’ activity than those on conventional diets.
In one study with growing horses, those fed higher fat and fiber feeds and a significant reduction in calories from starch and sugars had a lower bone mineral content, which may be attributable to reduced activity levels.
Behavior cannot be controlled entirely with a feed scoop. It’s not likely that a racehorse will transform to be a kid’s horse just by adding
fat to the diet. However, there are those horses that tend to get a little edgy or have nervous energy when fed ample grain to maintain body condition and support their work level. Often these horses become less excitable and more focused when some of the starch and sugar calories are replaced by calories from fat and fermentable fiber sources.
Behavior cannot be controlled entirely with a feed scoop. It’s not likely that a racehorse will transform to be a kid’s horse just by adding fat to the diet.
110 SPEEDHORSE November 2023
Fat supplementation for lactating mares provides the additional calories needed for milk production, without having to increase grain amounts.