Question

I own a 13-year-old stock-type mare that weighs about 900 lb (410 kg). My daughter uses her for light riding (4-5 days a week) and 4-H competition. She roams in a small, grassy paddock during the day, and she is corralled in a smaller pen at night. This mare was very thin when we got her, and we’ve been slowly adding weight. We feed her free-choice Bermuda hay and about 2.5 lb (1.1 kg) of concentrate a day. She’s getting a hay belly and her topline is still thin with ribs visible near her spine. I am thinking about changing her diet to include more concentrate, hay pellets, and less Bermuda hay.

Answer

Coarse, low-quality hay is notorious for giving horses hay bellies because of the amount of indigestible fiber that ends up filling the intestinal tract. Further, the Bermuda can be pretty low in protein, which is necessary for building muscle (topline), especially in a horse that was really down on her weight.

Hay pellets are made with good-quality forage that is easily digestible and won’t cause excessive gut fill.  Fortunately, hay pellets have adequate protein from the alfalfa in the pellets. For these reasons you may be better off with feeding more of the hay pellet and less of the hay. If you feed more of the hay pellet (perhaps 8-10 lb, 3.6-4.5 kg), I would still offer free-choice hay, but you may find her eating a lot less. Having something that takes longer to chew than a pellet is helpful for boredom and fulfilling the need to chew.

The other problem with the current diet is lack of fortification. You are feeding well under the recommended feeding rates for the concentrate. This affects protein, vitamin, and mineral intake. By increasing the concentrate to the manufacturer’s recommendations, you will resolve this issue and be on your way to providing a better diet for your mare.