Q: I have a 20-year-old Arabian/Paint gelding that I’ve had since he was 3 months old. He was always an easy keeper and I realized when he was around age 4 or 5 that he had equine metabolic syndrome (EMS).

From that day on, he’s consumed low-nonstructural-carbohydrate (NSC) hay and grain. Because he is an air fern, I’m always careful about what he eats and severely limit his grazing time; I keep him on a dry lot most of the time. At age 14 he developed pituitary pars intermedia dysfunction (PPID, formerly called equine Cushing’s disease). My veterinarian put him on 1.5 Prascend (pergolide) pills per day, which I administer in addition to Thyro-L (levothyroxine sodium).

Somewhere during all of this, my gelding started losing weight. He had a mild gastric ulcer attack a few years ago, so my veterinarian prescribed ranitidine, which she later replaced with cimetidine. Recently, he had another ulcer attack and currently has omeprazole added to his diet. My question is, how do you feed PPID, EMS, and ulcer-prone horses that need to gain weight? I already feed every four to five hours. Consuming oils never helped him, but soaked beet pulp has helped some.

A: Hello, I am sorry you’re having to handle these difficult issues. The first thing I recommend is having a good discussion with your veterinarian about your horse’s conditions to determine whether the current medications should stay the same or be adjusted. Veterinarians often prescribe Thyro-L to help horses regulate glucose and insulin and treat EMS. They also commonly prescribe Prascend, which you also mentioned, for horses with PPID. Both medications can cause weight loss—a side effect that usually benefits horses with EMS and PPID. However, your veterinarian might want to monitor the dosage and make adjustments if needed.

I am glad to hear your horse receives omeprazole for his ulcers. Currently it is the only FDA-approved medication for treatment and prevention of gastric ulcers in horses. I recommend talking with your veterinarian about whether you can discontinue this medication or reduce the dosage once management strategies help get the condition under control.

I would like to address feeding management of the three distinct disorders you mention—EMS, PPID, and gastric ulcers. Fortunately, some of the recommendations for managing these conditions overlap, which can make caring for your horse easier.

EMS

Horses with EMS tend to be easy keepers and carry extra weight, but you need to make sure you aren’t “starving” them to get them to an ideal weight. Forages low in NSCs should be the base of their diet. Typically, they should have only hay with little to no access to pasture, especially in fall and spring when pasture NSC levels tend to be higher. On a per-pound basis you’ll want to avoid feeding less than 1.5% of a horse’s body weight in hay. A low-calorie/low-sugar ration balancer can help you make sure you meet all his nutritional requirements. To help keep glucose and insulin levels steady, provide small, frequent meals and/or use a grazing muzzle to slow down feed intake.

PPID

Pituitary pars intermedia dysfunction cannot be managed with diet alone (hence, giving pergolide), but it can help. Overweight horses should receive a lower-calorie diet to promote weight loss, and horses with insulin resistance or insulin dysregulation (often referred to together as EMS), need a diet low in NSCs. If a horse with PPID has not been diagnosed with EMS, you can generally feed a balanced diet of forage and concentrates or a ration balancer, while monitoring weight to prevent excessive gain.

Gastric Ulcers

For horses prone to gastric ulcers, feeding recommendations try to decrease acidity (low pH) in the stomach. Horses are designed to be continuous feeders; some type of feed is in the stomach almost constantly. We can mimic this by providing horses with multiple small meals throughout the day and allowing free-choice access to forages. Nutritionists also recommend reducing the amount of concentrate a horse receives to address gastric pH. Higher-fat feeds tend to slow gastric emptying rate and are not as acidic as more traditional concentrates. Experts also suggest offering some feeds on the market that contain more complex carbohydrates. Adding a forage higher in calcium might also be beneficial, because it works as a natural antacid.

With both PPID and EMS the goal is to keep insulin levels regulated and maintain a horse’s body weight at a level that won’t predispose him to bouts of laminitis. I recommend you feed a good-quality mostly grass hay with an NSC level of less than 10%. If you can’t find hay with NSC levels below 10%, soak the lowest-NSC hay you can find for about 30 minutes prior to feeding to help reduce the sugar and starch content. Remember that you should not give your horses access to the soaking water because it will have all those undesirable carbohydrates in it. You should feed your horse about 2% of his body weight in forage daily—so about 20 pounds of hay for the average 1,000-pound horse.

I would also recommend a ration balancer if your horse maintains his weight on forage alone. Essentially, manufacturers design balancers to work as a vitamin and mineral supplement to ensure your horse gets the correct levels he needs. Make sure it is low in soluble carbohydrates. If he cannot maintain his weight on forage alone, then I recommend one of the higher-fiber feeds available. You mentioned your horse has consumed beet pulp, and it helped, whereas fats did not. Fortunately, many of these feeds have a beet-pulp base. These recommendations also work for the ulcer-prone horse, so they might help there as well.

It sounds like you are already taking many of the right steps for managing a horse with these three issues. Keep feeding meals more frequently and make sure you’re using low-NSC forages and feeds to maintain an appropriate body weight for your horse. I would be interested to hear what your veterinarian recommends related to the medications, and I wish you the best of luck.

Do you have an equine nutrition question?