When a horse is sick or recovering from illness, feeding choices can either help him on the road to recovery or send him further down the path of distress. Therefore, it's important to know what feeds and forages are better for sick horses and which ones aren't recommended.
Bryan Waldridge, DVM, MS, Dipl. ABVP, ACVIM, a veterinarian at Kentucky Equine Research (KER) in Versailles, Ky., presented a lecture on feeding sick and hospitalized horses at the 2012 KER Conference, held May 17-18 in Lexington, Ky.
He first discussed several reasons horses could cause a horse to stop eating before reviewing a few specific disorders and illnesses that can greatly benefit from careful nutritional management.
Why Aren't They Eating?
Waldridge first discussed some of the causes of anorexia in horses:
Fever: Waldridge explained that horses with fevers greater than greater than 101.5°F will often go off feed; when fevers reach 104° or 105° they definitely won't eat, he said. Many horses will start eating again once their fever is reduced, he said, which is often facilitated by non-steroidal anti-inflammatory drug (NSAID) administration. He also noted that it's important to determine the cause of the fever, as it could point to another, more serious, health problem.
Gastrointestinal illness: Horses with impactions, enteroliths (intestinal stones composed of minerals that build up around a foreign object that a horse eats but does not digest), and impending diarrhea will often opt out of eating, Waldridge said.
Respiratory illness: Like gastrointestinal problems, respiratory illness can cause horses to go off their feed. Waldridge noted horses with viral and/or bacterial infections or pleuropneumonia (inflammation both within the lung and within the pleural cavity) are especially vulnerable to anorexia.
Gastric ulcers: While gastric ulcers can cause anorexia in horses, Waldridge cautioned that the presence of ulcers doesn't confirm that the animal's clinical signs are caused by the ulcers. Oftentimes ulcers are a coincidental finding, he said. That said, he noted that many horses appear to feel better after being treated for ulcers, even if they are simply a coincidental finding. Also, some horses without gastric ulcers will regain appetite when treated with anti-ulcer drugs.
Metronidazole administration: Waldridge noted that one antibiotic medication, metronidazole, often causes horses to avoid food because of the less than desirable taste of the drug. "They don't want to eat it or anything around it," he said.
Dental disease: More common in older horses, dental problems can make it difficult or painful for even a healthy horse to eat. Waldridge suggested evaluating a patient's teeth, especially if no other causes of inappetance can be identified.
Colon acidosis: Caused by excessive starch and deficient forage in the diet, colon acidosis (abnormally high acidity in the large intestine/colon) often causes anorexia. Waldridge said green forage or grass can encourage these animals to begin eating again.
Lack of green grass: A simple lack of green grass can cause anorexia in horses, he said. Providing these horses with hand grazing or turnout, if possible, can help jump-start their appetite, he said.
Goal No. 1: Keep Them Eating
The number one goal when feeding a sick or hospitalized horse is to keep the horse eating to maintain body condition, Waldridge said. Thus, it might be necessary to feed horses a less than desirable food choice in moderation if the animal will not consume anything else, such as alfalfa hay rather than grass hay, he said. While discussing individual illnesses, Waldridge made recommendations on how to handle "picky eaters."
Next, Waldridge recommended feeding practices for horses with some specific conditions, recovery of which can be either helped or hindered by feeding decisions.
Hepatoencephalopathy--Brain and nervous system damage as a complication of liver disorders is referred to as hepatoencephalopathy. It typically occurs when the liver is damaged to the point it cannot remove gut-derived toxins, such as ammonia, from the horse's system. Clinical signs of hepatoencephalopathy include head pressing, changes in mentation or behavior, seizures, and neurologic deficits, and are more likely to occur after the horse eats, Waldridge said. A combination of clinical signs, blood work, an ultrasound examination, and a liver biopsy will aid in diagnosis, he added.
Along with medical and supportive treatment, horses with hepatoencephalopathy require special dietary management, Waldridge said, specifically a reduction in the amount of ammonia in the animal's body. To accomplish this, reduce horses' dietary protein to as little as 8% of their diet by feeding grass hay or pasture. Avoid offering horses forages high in protein, such as alfalfa or clover, he said. Additionally, he recommended spreading the feedings out over the course of the day to reduce large volumes of protein the liver needs to filter.
If a hepatoencephalopathic horse will only consume a high-protein legume forage, Waldridge said it should be fed in small quantities in moderation to keep the horse at a healthy body condition.
Hepatic Lipidosis--This life-threatening condition, which involves fat building up in the liver, is most commonly found in Miniature Horses, ponies, and donkeys, but can affect all horses. Waldridge explained hepatic lipidosis occurs during periods of severe inappetance or energy restriction, so it's crucial to get affected horses eating again. The condition is diagnosed by evaluating the horse's blood serum triglyceride concentration, the serum appearance, and liver enzyme activities.
Treatment is largely nutritionally based. To encourage food consumption, Waldridge recommends offering the animal different feed options and hand grazing, if possible. In some cases, nasogastric tube feeding or parenteral feeding might be required if the animal refuses to eat, he said.
Waldridge stressed that it's vital to treat the condition which caused the hepatic lipidosis aggressively to promote a full recovery.
Chronic kidney disease--When treating a horse with chronic kidney disease, Waldridge said, it's essential to keep the horse eating and drinking normally. Diagnosis of this disorder includes identifying elevated renal indices, hyposthenuria (excretion of dilute urine or water loss), casts (kidney cells accumulated in the tubule) in urine, and an ultrasound exam.
When feeding a horse with kidney disease, aim to avoid dietary protein, which causes the horse to urinate excessively and further damages already ailing kidneys, Waldridge said. Also, restrict calcium intake to reduce the amount of the substance the kidneys must extract into the urine, he said. This can be accomplished by feeding high quality grass hay or pasture, and avoiding legume forages with high protein and calcium concentrations. Again, the most important point is to keep the horse eating to maintain a healthy body score; use legumes sparingly if the horse will not eat anything else.
Waldridge also noted providing the patient with one to two ounces of salt, once or twice daily could encourage the horse to drink more, and supplementing his diet with omega-3 fatty acids could aide in reducing renal inflammation.
Respiratory disease--Horses with respiratory ailments--such as recurrent airway obstruction (RAO, also known as heaves) and inflammatory airway disease (IAD)--have special dietary needs as well, Waldridge relayed. Since the clinical signs of both RAO and IDA are intensified by inhaled particles, Waldridge stressed the importance of reducing particles in the horse's breathing zone. Most irritating particles, he said, can be found in the horse's hay. Thus, when feeding affected horses, it's important to consider either taking steps to reduce hay dust or alternative forage sources:
When selecting a hay, choose one baled at 15 to 20% moisture content. This is the ideal moisture content that doesn't promote heat buildup while reducing the favorability of the environment for mold spore development;
Soaking hay reduces dust concentrations in hay, but studies have also shown that soaking for as little as 30 minutes can reduce the nutritional content of the forage, Waldridge said;
Steaming hay, a relatively new method of dust control, has been proven effective in maintaining hay nutrition while reducing fungal and bacterial spore growth by more than 95%, he noted;
Haylage, Waldridge explained, is preferable to hay for horses with respiratory conditions, as it has been shown to reduce dust concentrations by up to 93%;
Feeding hay cubes is another viable option for horses with respiratory conditions, as cubes have been shown to reduce the amount of dust in the horse's breathing zone, and to have low fungal spore concentration and no pollen; and
Pelleted Hay has been shown to reduce the concentration of dust in horses' breathing zones to just 3% when compared to hay, Waldridge said.
Nutritional choices can either help or hinder a horse's health problems, diseases, or ailments. By understanding why certain feeds are recommended or not for a certain condition and working with a veterinarian, horse owners can help their horses on the road to recovery.