Question
I have a 22-year-old gelding named Linus that’s moderately thin. He was diagnosed with polysaccharide storage myopathy (PSSM) years ago. Once Re-Leve came on the market, we switched to that plus corn oil. He did great on this until a few months ago, when he stopped eating it completely. He has also been diagnosed with pituitary pars intermedia dysfunction (PPID or Cushing’s syndrome) and is on pergolide mesylate. I have tried feeding him other feeds with oil on them, and he refuses anything with added oil. The only feed, besides treats and hay, that he finishes off is a mash consisting of beet pulp and senior feed. Currently on 5 lb (2.3 kg) per day of a 25% fat supplement, a hoof supplement, and added molasses. He also gets 6 flakes of grass hay as well as a flake of alfalfa four days a week. He’s not fond of the fat supplement, and he won’t touch it without the molasses. As you know, he shouldn’t have the molasses. He needs to gain weight, but my dilemma is probably obvious now. He’s turned out 6 days a week for about 2 hours.
Answer
Has Linus’s appetite improved since you submitted his diet information to us? Did he first go off feed when the PPID treatment started? I ask specifically because it isn’t uncommon to hear horses experiencing loss of appetite when they start pergolide or have a change in dosing. If his lack of appetite corresponds to treatment, consultation with your veterinarian may be necessary to find the correct balance between his treatment, appetite, and well-being.
Is Linus’s current diet just 5 lb (2.3 kg) of high-fat supplement or a combination of this and beet pulp/senior mixture? In terms of alternative feeds, you may try other high-fat feeds, ranging from 10% to 14% fat, with reduced starch and sugar content (21-23% max), which would allow you to offer just one feed rather than a combination of feeds to achieve the desired starch and fat levels. Again, there’s no guarantee he will eat one of these, considering the tribulations you’ve had with appetite to date. You may also find that, when Linus’s appetite returns after being on the medication, he may happily consume his original diet of Re-Leve.
If you have ruled out PPID treatment as a cause of his inappetence, then assessing him for digestive upset would be the next step. Gastric ulcers and hindgut disturbances can cause horses to go off feed. In these cases, horses require evaluation and may benefit from the addition of a digestive buffer.
Kentucky Equine Research (KER) developed two digestive health products, RiteTrac and EquiShure, to help horses maintain optimal digestive health and function. Both of the products are available in the U.S., and EquiShure is also available in Australia.
To help support horses with Cushing’s disease, I recommend providing daily supplementation of omega-3 fatty acids. EO•3 is a marine-derived source of the omega-3 fatty acids EPA and DHA. These omega-3 fatty acids offer anti-inflammatory properties that can help reduce the inflammation associated with aging and Cushing’s disease. In addition to the anti-inflammatory properties, omega-3 fatty acids can also help improve insulin sensitivity. EO•3 is a palatable deodorized fish oil with cherry flavor; introducing EO-3 to the diet should be done gradually to ensure optimal acceptance of the product. I would be cautious to add this to Linus’s diet at this time, as it may reduce his willingness to eat further if top-dressed onto his feed. However, this is an excellent product to keep in mind.
