Feeding Sick Horses

Blossom is a sorry sight. Suffering from the symptoms of strangles--fever, a snotty nose, and depression--she's been standing with her head in one corner of her isolation stall for hours now, barely moving. What's worse, her morning grain is untouched, and her hay has become part of her bedding, largely un-eaten. Never a plump mare, she seems to have dropped 100 pounds in the past two days as she rides out the infection, and you're starting to become concerned about her condition. Her lungs and sinuses might clear within the week, but the weight loss could take much longer to address.

Even sadder is your friend's gelding, Custard, who underwent emergency colic surgery two days ago. Fortunately, he pulled through, and will be ready to go home in a few more days...but your friend is worried about what to feed him. What can his patched-together digestive system handle now? What might throw him into a relapse?

Feeding a healthy horse is one thing; most of us have a pretty good understanding of what works and what doesn't. But feeding a horse who's sick, injured, or recovering from surgery is another. Not only do you have to worry about what his compromised system might be able to handle, but you also have to deal with potentially dramatic weight loss, and the anorexia (loss of appetite) that often comes with fighting illness or injury. Getting your patient to eat is half the battle. The other half is helping him maintain (or improve) his condition so his body will have the best chance of returning back to health.

Dealing With Lost Appetite

Exactly how you design a diet for an ill or injured horse depends largely on the problem. For an otherwise healthy horse which is put on stall rest because of, say, a bowed tendon, reducing his overall caloric intake to match his sudden switch from active athlete to captive patient is the most important thing. If that doesn't occur, he's likely to "blimp out" and become obnoxious to handle. In most cases, such a horse should be taken off grain altogether and placed on a high-fiber, long-stemmed hay diet that will supply his maintenance needs and occupy some of those lonely hours in the stall. However, unless confinement brings on a case of severe depression (as it sometimes does), he won't be likely to suffer any loss of appetite; so for the most part, the dietary considerations of a horse on stall rest are uncomplicated. Free choice moderate to good quality grass hay, salt, and water should suffice for most stall-bound adult horses.

Some horses maintain a robust appetite in the face of anything short of nuclear war, while others are likely to go off their feed at the slightest provocation. A loss of appetite can stem from a compromised ability to taste or smell, from a decreased ability to chew and/or digest (stemming from facial, oral, pharyngeal, esophageal, or intestinal problems), or simply from pain, fear, or stress associated with an illness or disease. Picture the swollen jaw of poor Blossom, our horse with strangles, and it's easy to see why she would be reluctant to eat. Influenza, the respiratory form of equine herpesvirus (EHV), pigeon fever, Lyme disease, and Potomac horse fever, to name a few diseases, as well as chronic conditions like equine protozoal myeloencephalitis--all can affect a horse's appetite.

Regardless of the cause, it's important to recognize that inadequate feed intake is more than just a symptom. It adversely affects all of the body's systems, and makes it much more difficult for the horse to fight off disease, heal an injury, or respond to therapy. In fact, the immune system can be compromised by inadequate nutrition in as little as five days. Getting feed into your horse on a regular basis throughout his troubles will help reduce the number and severity of any complications he might suffer, and will shorten his recovery time significantly.

As the saying goes, "You can lead a horse to water, but..." You can lead him to his feed bucket, too, but getting him to consume the goodies within might be another matter. Be prepared to go the extra mile and concoct feeds that are extra-tempting to help him keep his strength up. The traditional bran mash is a bit overrated as a convalescent diet: its fiber content is not terribly digestible, it has an inverted calcium/phosphorus ratio that could cause bone density problems if fed on a daily basis, and if suddenly fed in large amounts it may trigger a mild digestive upset, resulting in loose manure. But it has two important advantages: most equines love the taste, and it is a good source of protein for healing tissue.

If you're faced with a patient which refuses to eat, a warm, sloppy bran mash, laced with dollops of molasses and a generous pinch of salt, might be just the thing to jump-start his appetite. (It also can be a good place to hide oral medications.) Adding two to four ounces of brewers yeast or another vitamin B complex source also can help. Although horses normally normally do not need vitamin B supplements, stress increases the need for the B vitamins and anorexia is one of the first signs of deficiency in other animals. But once you've gotten your horse to put his nose back in his feed bucket, gradually wean him off the bran and back to his regular diet. A few sliced carrots or a little molasses, corn syrup, or honey might be enough to encourage him to clean up his meals; be willing to experiment. Harvest some green grass for him if he can't be let out to graze. If pain is the reason your horse won't eat, you might want to ask your veterinarian about administering a non-steroidal anti-inflammatory drug such as phenylbutazone. Some vets might prescribe anabolic steroids to help stimulate the appetite, but the effect usually isn't apparent for a few days and long-term use can depress the immune system. Not something you want in an already ill horse.

If all attempts to jump-start your horse's appetite fail, don't hesitate to seek more drastic solutions. Complete food deprivation for more than three to five days not only suppresses the immune system, it often can trigger diarrhea. In severe cases, diarrhea can be fatal. Your veterinarian might recommend hospitalization so that your horse can be tube-fed or placed on intravenous nutrient solutions (more on those in a moment).

Special Cases

Maintenance rations are adequate for most sick horses, according to Sarah Ralston, PhD, an equine nutritionist at Rutgers University. But before you determine whether that's going to be the case for your horse, consider his current body condition. Was he overweight or underweight before the onset of his troubles, or was he right where you'd like him to be? Deciding this will help you figure out whether you'll be feeding him for maintenance, weight loss, or weight gain. Use a heart-girth weight tape to get a rough estimate of his weight, and monitor him for changes while he's recuperating.

As long as your horse's ability to chew and digest isn't compromised, try to avoid drastic changes in his diet while he's recovering or under forced stall rest. Don't make an abrupt switch from grass hay to alfalfa, for example, in the mistaken belief that the extra protein or calcium will do him good. You'll likely just trigger a digestive upset on top of his other health problems. Any changes you do make to the diet should, as always, be done gradually, over the course of a few days.

Some types of severe trauma, such as burns from a barn fire, or sepsis (severe infection), make enormous energy demands on an afflicted horse. In order to bounce back from such challenges, his need for fluids, protein, water-soluble vitamins, and dietary energy will soar, up to 100% over his normal maintenance needs. Ralston recommends a diet that provides 14%-16% crude protein, 7%-10% fat, and high levels of B complex vitamins, vitamin C (10 g, twice a day), and vitamin E (1000 IU/day), initiated immediately after the trauma occurs and maintained until the horse is clearly out of the woods.

Remember, to start slowly with small amounts on the first day and gradually increasing the amounts of the richer (higher fat and protein) feeds over three to four days.

Horses with liver failure (often geriatrics) have trouble processing excess protein and fat, especially the "aromatic" amino acids such as tryptophan, but can benefit from a diet supplemented with the short branched-chain amino acids leucine, isoleucine, and valine. Grains such as corn or milo can help satisfy those requirements better than oats. Because a compromised liver can't synthesize glucose as it should, affected horses also benefit from a high-starch diet, which will make glucose more readily available to the body. Thus, a diet that is 50% grain often is recommended. B vitamins, especially thiamin and niacin, should be supplemented (brewers yeast is one easy way to do this).

Horses with liver failure should not be fed high-fat diets, and their salt intake should be limited, or at least not augmented, as it could contribute to edema (accumulation of fluid in cells). Feeding three to six small meals a day also seems to ease digestion for liver-impaired equines.

Chronic kidney failure is another problem many geriatric horses face, and it's often coupled with depression and a loss of appetite. When the kidneys aren't functioning as they should, the horse has trouble excreting metabolic wastes, especially urea (the byproduct of excess protein in the diet), calcium, and phosphorus. A diet based on grass forage can successfully limit the intake of excess protein and minerals, with corn added if more calories are needed for weight maintenance.

Alfalfa, wheat bran, and rice bran should be avoided since they contain high levels of protein, calcium, and/or phosphorus. Again, supplementing B vitamins might be beneficial.

It's also important to make fresh water abundantly available to kidney-impaired horses. Because their kidneys can't concentrate urine and conserve water as they normally would, they need plenty of liquid to help flush waste products out of their bodies, and a shortage can result in dehydration and death.

Owners of horses which have tested positive for hyperkalemic periodic paralysis (HYPP), a genetic defect traced to the Quarter Horse stallion Impressive, need to restrict the amount of potassium in their animals' diets. The disease, which is due to a defect in the muscle membrane's permeability to sodium, results in "leakage" of potassium out of muscle cells. The alteration in the electrolyte balance across the cell membranes increases the muscle's excitability and electrical activity, causing HYPP's characteristic tremors or seizures.

Restricting potassium is a matter of avoiding molasses, oilseed meals, and growing or immature forages (all of which are high in this mineral), and feeding a high-carbohydrate diet of straight grains, along with mature grass hay. Electrolyte solutions and many vitamin/mineral supplements also should be avoided as they often contain potassium. There now are commercial low-potassium feeds available specifically for horses with HYPP; when fed as recommended, they can be very effective at reducing the incidence of HYPP episodes.

Surgical Scenarios

One would imagine that the stitched-together innards of a horse which recently had undergone colic surgery would be unable to handle solid food for days. In fact, the opposite often is true. Ralston recommends that after an intestinal resection, feed should be re-introduced as quickly as possible--within 24 to 48 hours, ideally. The reason? Prolonged fasting (for more than 72 hours) might result in atrophy of the intestinal mucosa, compromised healing of the wound, and an increased susceptibility to diarrhea and infection.

There are no long-term special dietary requirements for a horse recovering from colic surgery where no portions of the intestine were removed, or even when the cecum or less than 50% of the duodenum and/or jejunum were resected, Ralston says. Hay can be offered, in small amounts, within hours of the horse shaking off the anesthetic, starting at about a quarter of what he normally would eat (assuming there is no concern about suture line integrity and the horse's gut motility has returned to somewhat normal). Immediately post op, the horse should be offered top-quality hay and limited, if any, grain. After a week or so, assuming no complications, he can be put on the stall-bound diet described above and returned to his normal rations (assuming they were balanced and not the cause of the colic!) once removed from exercise restriction.

However, if portions of the large colon were removed during the surgery, the recovering horse will need extra protein (more than 12%) and phosphorus (at least 0.4%), and decreased fiber, says Ralston, to compensate for the gut's decreased ability to process these nutrients for the rest of its life. She suggests alfalfa hay, or an alfalfa/grass mix, with small amounts of grain (no more than one to two pounds per meal) offered if the horse needs additional calories to maintain or gain weight. A good commercial ration designed for young, growing horses might be appropriate. Supplemental fat, in the form of corn oil, rice bran, or a commercial high-fat supplement, also might help increase his caloric intake.

If the surgery involved a major resection of the small intestine, grain should be avoided post op. The horse should be fed a high-quality legume hay and a beet pulp-based concentrate. A horse which has lost portions of his ileum will be less able to absorb fats and fat soluble vitamins, and thus will need his diet supplemented with the fat-soluble vitamins A, D, and E. Ralston suggests supplementing vitamin K only if the horse develops bleeding problems. Your horse might have an increased need for calcium, since the small intestine is the primary site for calcium absorption. However, if he is eating a legume-based forage, the calcium contained in the hay should suffice.

In some cases, if the surgeon suspects that there might be a postoperative risk of the incision(s) gaping or tearing open, it is necessary to provide the patient's gut with feed that can be processed easily and swiftly. Hay cubes or complete pelleted feeds, soaked in warm water to make a "soup," might be the best answer for the first few days. If these larger particles are poorly tolerated, the horse can be given a concentrated liquid diet based on human products like Ensure. At approximately one calorie per milliliter, it takes about 16 liters of Ensure to fully supply a horse's nutritional needs. This is not very practical, even by stomach tube, but the liquid is useful as a supplement for short periods of time if the surgeon is concerned about the integrity of the suture lines.

In the case of very extensive or complicated surgeries, where the horse is too weak to eat for more than 24 to 36 hours after the procedure, his caretakers might have to resort to feeding intravenously. Standard solutions with 5% dextrose won't provide enough nutrition.

Ralston suggests intravenous amino acid and lipid solutions, such as those used in human medicine. It can be very expensive to try to meet all of a horse's nutrient needs intravenously, but even 50% is better than nothing. The reduced incidence of complications and more rapid healing of even a partially nourished postoperative horse outweigh the initial expense.

Making Minor Manure

A rare, but serious complication of foaling is tearing between the mare's vaginal and rectal passages. These tears have to be repaired surgically and as you might imagine, there's an urgent need to soften and reduce the mare's fecal volume so as not to induce straining, tearing of the suture line, and subsequent infection. The volume of manure can be reduced. Before and after surgery, a high-energy complete pelleted feed, soaked in water and fed with up to 20 ml of vegetable oil per kilogram of feed, is the best choice, providing sufficient feed energy without high volume. Keep in mind that the mare is probably still lactating and that the concentrates should be balanced for her increased protein and mineral needs. Again, the mare should be switched slowly to the low fiber diet, over the course of a week or so before the surgery is scheduled. Offer it in small amounts at frequent intervals to reduce boredom and wood chewing that invariably occurs in horses fed low fiber diets. Long stemmed hay should be avoided until healing is well advanced, although soaked hay cubes or fresh pasture grass can be introduced to provide some forage content.

I sincerely hope that none of the scenarios discussed here ever occurs in your barn, but should you find yourself faced with an ill, injured, or hospitalized horse, at least you'll have an idea of how you and your veterinarian will manage his nutritional requirements. Here's to speedy recoveries and returning to "eating like a horse."

About the Author

Karen Briggs

Karen Briggs is the author of six books, including the recently updated Understanding Equine Nutrition as well as Understanding The Pony, both published by Eclipse Press. She's written a few thousand articles on subjects ranging from guttural pouch infections to how to compost your manure. She is also a Canadian certified riding coach, an equine nutritionist, and works in media relations for the harness racing industry. She lives with her band of off-the-track Thoroughbreds on a farm near Guelph, Ontario, and dabbles in eventing.

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