Recent events in Orange, VA have had a powerful emotional impact on many people in and out of the equestrian community. Images of severely thin horses have inspired many good hearted people to offer help and care to the affected horses, either through donations, fostering, or both. It is important to realize, though, that it is actually possible to kill a starving animal with kindness.
During prolonged periods of inadequate nutrition, several changes occur in the body. First, there are changes in the gut. Digestive enzymes are reduced when there is less to digest. The population of organisms that live in the gastrointestinal tract also changes in response to diet. If the feed is poor quality, the types of bugs change. If there isn’t much of anything coming in, the populations die out. Thus, chronically malnourished horses have different, and smaller populations of, GI bugs than well fed ones do.
Secondly, when the incoming calories are too few to support the needs of the animal, the body consumes its own stores. First, it uses up stored carbohydrates and fat. Once these supplies run low, the body starts to consume its muscle tissue as a source of protein. The body breaks down the skeletal muscles first, but the heart muscle and other organ tissue may also be consumed. This can make the heart weak and reduce kidney and liver function.
Once these changes are in place, any rapid changes in diet can cause catastrophic events. Increasing the blood glucose through feeding carbohydrates causes insulin to be released, which moves not only blood glucose, but also essential (and depleted) ions into cells. This leads to neurologic abnormalities, deterioration of red blood cells, liver failure, heart failure, and death. Rapidly increasing the amount of feed in an unaccustomed gut can result in diarrhea, colic, and founder.
Thus, it is essential to change the diet of malnourished horses very slowly. For the first several days, the horse should not receive any concentrate (pellets or grain) feed at all, and should only be fed very small meals (1/4-1/2 flake of hay) every 4-6 hours. This allows the gut to start to gear back up, and avoids big spikes in glucose (and therefore insulin). Horses can graze for 2-3 hours, increasing pasture time by an hour every 3 days. During this time, the horse should have access to minerals and unlimited access to fresh water.
After the first 2-3 days of eating just small meals frequently, the amount of hay can be increased to just meet caloric needs of the horse in its thin body condition for 3 more days. Then, feed can be increased over a 7-10 day period to start supplying enough energy for the horse at its ideal body weight. During the period of weight gain, carbohydrates should still be less than 20% of the ration. Senior feeds are typically alfalfa based, easily digestible, and an excellent source of protein and calories for recovering horses. Introduction of these feeds should also be done slowly, starting at ½ a pound twice daily and increased every 2-3 days as needed. If the horse is not gaining weight as expected, fats can be slowly introduced into the diet, but not until after 10-14 days after the horse is adapted to its new diet.
Once the horse has adapted to a more normal diet, it should have free choice access to good quality grass hay and/or pasture. Supplemental feeding should be provided to meet the needs of the horse’s target weight. The process of weight gain should proceed slowly; very thin horses will take 6-10 months to return to a normal body condition when fed back properly.
Unfortunately, some horses will not recover from chronic malnutrition, even with meticulous attention to nutrition. Horses that have lost half of their body weight, or are too weak to stand have a very poor chance of recovering. The best chance any horse has of recovering from starvation is providing a gradual transition back to eating to allow its body to adapt to a more normal state.
Tracy Norman, VMD, ACVIM