I have a 14 yo anglo-arab mare. She is a distance horse competing in Competitive Trail Rides — usually 30-mile rides. I would like to make sure she is getting enough fat in her diet and would like to know if I need to give her glycogen supplements? She is 15.3 and 1100 lbs. I feed her 2 lbs of beet pulp, 1/4 c of apple cider vinegar with 30ml of flaxseed oil, electrolytes and 1 cup of rice bran (all wetted down with water) twice a day. I do give her a joint supplement and Vitamin E/Selenium along with full vitamin and amino acid in am feeding. In addition she is feed 2 flakes of alfalfa and 1 flake of timothy twice a day. Kim

Dear Kim,

Before getting in to the specifics of your sport, I’m going to approach your horse’s diet from the beginning. Since you didn’t mention a weight problem (either too high or too low), I’m going to assume your mare is right where you want her, probably a 4.5 to 5 on the BCS scale for endurance riding. Forage is the basis of equine nutrition so let’s start there!

Horses require about 2% of their body weight per day in feedstuffs and at least half of that (1%) should be forage. So an 1100lb (500kg, thanks for making the math easy!) horse needs about 22lbs of food daily and at least 11lbs of that as forage. I’m going to guess that your grass flakes of hay weigh 2lbs each and your alfalfa flakes weigh 3lbs each so that’s 8lbs of hay morning and night for a total of 16lbs of hay. That plus the 2lbs of beet pulp (assuming that’s the unsoaked weight) equals 18lbs, right in the middle of the range so good for you!

You mention you’re feeding a “full vitamin and amino acid” in the morning feeding. This should be balanced for the predominantly alfalfa forage you’re giving her. Since it also contains amino acids (protein), I assume this is a ration balancer and not just a multi-vitamin/mineral supplement. I think the electrolytes and Vitamin E/Se (as long as there’s not too much already in the forage) are a good idea.

Now for the fat. Thirty mls of flaxseed oil provides her with healthy omega 3 fatty acids, which is a plus. It’s 100% fat and roughly 30 grams, which is not much compared to the 18+ pounds of forage she’s getting (a little over 8kg or 8,000 grams!) And the one cup (8 ounces) of hopefully fortified rice bran is only providing 45 grams of fat (20% of 8 ounces, check my math). So you’re two fat sources together add up to less than 80 grams of fat, 1% of the diet by weight.

Given the benefits of fat supplementation to your sport—including a glycogen sparing effect—I recommend you slowly add more fat to her diet and let her muscles learn to prefer it for energy in the middle miles and save their stored glycogen for fast starts and fast finishes. My preferred fat source is Cool Calories 100, which is a fantastic smelling, 100% powdered fat that horses love. My own horse, Newman, is its biggest fan!