Question
I own a four-year-old, 15.3-hand Appaloosa mare that consumes this diet daily: five flakes of mixed grass hay divided into four feedings; minimal grass in a small paddock; and two small coffee cans of textured feed and two cups of a ration balancer (divided into two feedings). This mare has been healthy her entire life. A few days ago she became very sore in her paddock. The vet concluded she was foundering slightly from grass. We treated her, and she was sound the next day with no heat in her feet. Our vet recommended keeping her off grass. What caused this episode? Should I give her a different grain? I have never had a horse founder, as I am very careful with my mare's weight and feeding.
Answer
It is often very difficult to nail down the exact cause of founder, but obviously something tipped your mare over the edge. Some possibilities might be the growth of grass caused by the rains (which would be very high in sugars), fever, or even the combination of a fresh trim with the high-sugar grass. This may be a one-time problem or a recurring one.
Understanding how to diminish the risk factors may help prevent it from happening again. Keeping your mare at the ideal weight and not letting her gain too much weight is key to preventing further problems, particularly if she is insulin resistant. You may have to be prudent about time out on grass during any fresh growth (spring or fall, or when the grass turns green after a rain from a drought). Muzzling the horse while turned out may decrease the consumption of grass to the point where it is not a problem.
Feed as little concentrate as necessary to meet the energy and nutrient requirements of the horse. Choose a feed that is high in digestible sources of fiber and low in starch. Maintain a consistent exercise program.
Your feeding program seems very sound for a horse that may be susceptible to founder. KER Team Member Brooks Feed has two Phase V products, one textured and one pelleted. The pelleted version is ideal for this type of horse. There is a slight difference in nonstructural carbohydrates (NSC) between the two, with the pelleted being lower. Because you are feeding such a small amount, it should make no difference whether you feed the pelleted or textured.
I like that you are adding the All-Phase to compensate for feeding less Phase V than recommended, which is ideal, and All-Phase is low-NSC as well. If you cut down the amount of Phase V you feed, then you will need to feed more All-Phase. In general, for every pound (0.5 kg) below the recommended feeding rate add ¼ pound (1 cup) of All-Phase. Match the intake to the body condition needs of the horse, and your horse should do well.
