Nutrition for Rehabilitating the Starved Horse

In humans suffering from starvation caused by illnesses such as anorexia, cancer, or gastrointestinal obstruction, patients can develop “refeeding syndrome” when they are given concentrated calories, which in turn can lead to heart, respiratory, and kidney failure three to five days after the initial meal. This same syndrome has been reported in the literature for horses. Thus, University of California, Davis (UC Davis), researchers have developed a refeeding program for horses that would minimize these effects and enable the horse to gradually return to normal body weight.

What Happens During Starvation

During the starvation process, the horse initially uses any fat and carbohydrate stores in his body to supply energy for metabolism. This is the normal process for any healthy horse: fat and carbohydrates are used for energy, exercise, brain function, circulation, etc. and are then replaced with nutrients from food. The cycle is constant and never-ending, even during sleep. In a starved animal, once this source of fat and carbohydrates is gone, energy is derived from the breakdown of protein.

While protein is a component of every tissue, there are no inert stores of it in the body such as there are for fat and carbohydrates. Consequently, the starved body uses protein not only from the muscles, but also from vital tissues such as the heart and even gastrointestinal tissues – tissue that is necessary for life. The starved body cannot select which tissue protein will be metabolized for energy. As time goes by, the horse’s survival is in a precarious situation. When a horse loses more than 50 percent of its body weight, the prognosis for survival is extremely poor.

In a study on the effects of different types of feed used for refeeding starved horses, we selected three that were very different in nutrient composition: alfalfa hay, oat hay, and a commercially available complete feed consisting of grain, molasses, fat, and alfalfa. Alfalfa hay is known to be high in protein (20 percent) but low in the carbohydrate starch (3 percent). Oat hay is high in fibre but low in protein (7 percent). The complete feed represented a feed high in carbohydrate concentration with 19 percent starch.

The three types of feed were given to 22 starved horses that were brought to the UC Davis research site as representative of horses rescued by equine organizations. Horses were fed one of the three diets over a ten day rehabilitation period. The researchers focused on this time period as critical to successfully transitioning the gut from a starved state to a fed state. Even though the diets were different in composition, they were fed in amounts that were equivalent on a caloric basis so that horses assigned the oat hay diet, for example, received the largest volume of feed, while the horses on the complete feed received the smallest amount but the same number of calories at each meal.