Pamela M. Richardson
Lifelong dedication to equine health drives a UC Davis extension specialist to find answers to so-called “refeeding syndrome” in starved horses.
Excitement mounted as the horse trailer rounded a turn and started down the long driveway that leads to the Animal Research Complex at the University of California at Davis. It was a warm day in May 1999, and for the waiting team of researchers and student assistants, a momentous occasion. After months of preparation, they were about to begin the first phase of a nutritional rehabilitation study that would someday make a difference in the lives of countless horses who are victims of starvation. The book study and lab work was done; now it was time to do something that mattered. The arrival of the trailer represented the crucial link between science and reality.
The first horse, a gelding, was slowly led down the ramp. Instead of the sleek, muscular body that we normally associate with equines, the horse was so slight and lacking in flesh that his hip bones jutted out against his skin, and his withers were high and sharp. His coat, a dull chestnut color, was draped over his bones like a rug, and his head, which seemed too large for his body, hung down low at the end of a skinny neck. Flies buzzed mercilessly around the horse’s face, but the gelding, too exhausted to even shake his head, just closed his eyes. While the students dealt with the almost physical shock of the horse’s condition, Carolyn L. Stull, Ph.D., the principal researcher, struggled with her own mixed emotions.
Searching for Answers
An extension specialist in the Animal Welfare Program at UC Davis, Stull has dedicated her life to improving the health of equines. In her field, sadly, horse starvation is not an uncommon occurrence, and Stull had been constantly dismayed at the number of victims discovered every year. Even more frustrating was not knowing exactly what needed to be done to restore rescued horses to health. Rehabilitating a horse in this condition is a sensitive, dangerous task, and the simple fact was that no one knew the best strategy for saving a horse who was teetering on the brink of survival.
“Chronically malnourished horses often do not respond successfully to refeeding,” Stull notes, “and may even die due to something called ‘refeeding syndrome’—a complex array of physiological disorders that can occur during the rehabilitation process.” In practice, horse starvation victims, who have already suffered through a terrible experience, are often at the mercy of their rescuers, who are at a loss as to what, how much and how fast to renourish them. Oat or grass hay, for instance, might be too bulky to provide adequate quantities and quality of calories and nutrients. Leafy, nutrient-dense alfalfa hay, on the other hand, can induce gastrointestinal problems in horses not previously adapted to it, while concentrated pelleted feed could elicit an exaggerated insulin response. “When a nutritionist looked for assistance,” recalls Stull, “there was really no science on which to base her recommendations.” But one thing was certain: more than ample food and fresh water was needed. Any horse who has lost 50 percent of his normal body weight has a tough road ahead.
The nutritional rehabilitation project began in 1998, when Stull, in a quest for answers, described the situation to Purina Mills, Inc., in St. Louis. The company, which manufactures and distributes pet and livestock feed, appreciated that the problem deserved a solution, and offered to fund the project. With the help of Christine Witham, D.V.M., of UC Davis Veterinary Medicine Extension, Pamela Hullinger, D.V.M., of the California Department of Food and Agriculture, and Anne Rodiek, Ph.D., from Cal State Fresno, Stull designed a study that would lead to a better understanding of how chronically starved horses respond physiologically to refeeding.
Obtaining horses for the project was the first step, and it wasn’t long before Stull was alerted to an urgent situation in the Southwest. Reports were coming in of large numbers of very thin horses showing up at auctions. It seemed that horses had been turned out into fields that in the past had provided adequate nourishment, and were left there for the summer, all but forgotten. That year, however, severe drought conditions had developed by mid-season, and the lush pasture was transformed into a desert. By the time the situation was discovered, the horses were in critical condition. Stull saw opportunity, and for one herd of 22 horses, there would be a second chance at life.
The Lucky Ones
The mixed-breed horses ranged in age from three to 24 years and weighed between 532 and 878 pounds. Normal weights for these animals would have been between 950 and 1150 pounds. Once unloaded from the trailer, the horses were immediately placed in stalls lined with rubber mats (the stalls were barren of any bedding material for fear that the horses would eat it). Next the horses were randomly separated into three groups. Group 1 was fed a diet of oat hay; Group 2, alfalfa hay; and Group 3, a mixture of oat hay and commercially prepared grain. All three diets had been used successfully in similar circumstances in the past. Stull hoped to determine which of the three was most effective. The feed was introduced gradually over a period of 10 days, and the horses were weighed and tested daily.
At first the students assigned each horse a number for ease of data collection. It wasn’t long, however, before nicknames began to emerge. “Abraham Lincoln,” a long-bodied gelding with quiet, concerned eyes, was notably soft and deliberate in everything from his nicker to his walk. “Waterford Crystal” was a dainty, elegant mare with a long, full tail that the students loved to brush. Several days into the study, Crystal became depressed and wouldn’t eat. This problem, common during the rehabilitation process, led several of the students to grab scissors and cut fresh forage for the mare in the hope that the fresh oat hay, as opposed to baled hay, might stimulate her appetite. It worked, and Crystal was soon making progress again.
“Powdered Sugar” was cautious and shy, while her neighbor, “Lady Remington,” was considered a “10” in manners and behavior. Easy to handle and never pushy while being fed, she was perfect for the least experienced students to work with. Stull herself found “Harry,” a sweet gelding with a rough haircoat, the most memorable. She recalls something Harry did on the morning of first feeding. “I fed all the horses their assigned meal, and they all dug right in. Several minutes later, as I checked on each horse, Harry raised his head and let out a high-pitched whinny directly at me. I’ve fed many horses who nicker prior to feeding, but never has a horse nickered to me after chowing down. Maybe he was in ecstasy after such a long period of deprivation. I’ll never know, and it
doesn’t matter, but he seemed to really appreciate the meal.”
The scientists and students were hopeful as they watched the horses slowly improve over the 10-day period. By the end of the study, most of the horses were well on their way to recovery. With plenty of water, and high-quality feed provided in controlled amounts, their bodies began to fill out, their dull coats began to improve and their personalities started to emerge. For most of the horses, life had begun again.
Unfortunately, the risk of complications is present during every rehabilitation effort. Just when it seems that the animal has a fighting chance, an incident occurs to remind everyone of just how sensitive the process is. Sadly, three horses did not survive the study. One succumbed to Salmonella infection and another to a twisted colon—neither of which was directly related to the diet they were fed. A third horse developed neurological problems as a result of inadequate stores of essential electrolytes and minerals. In each case, too much physiological damage had already occurred by the time the rescue attempts were implemented—a not-uncommon occurrence. In order to end their suffering, the three horses were humanely euthanized. Everyone was heartbroken over these losses, but watched with hope as the 19 remaining equines, so fragile only two weeks earlier, slowly regained strength and health.
And the Winner Is…
When the data were collected and analyzed, the results were surprising. Within the horse-rescue community, a typical reaction to the idea of feeding straight alfalfa hay to a starved horse is, “You can’t do it. You’ll founder (cause to collapse from overfeeding) them.” Yet the sweet, leafy alfalfa turned out to work best. “We haven’t foundered a horse yet!” notes Stull.
The winning strategy was to feed the alfalfa diet in small, frequent meals (every four hours) during the first 10 to 14 days—the critical period of rehabilitation. This regimen provides a small quantity of feed with concentrated nutrients, especially minerals and electrolytes. “You want to introduce small quantities of feed to assist the gut in restoring its full digestive function, and not to distend the delicate digestive membranes by overfilling,” Stull says. “Weight gain may not be apparent for two weeks. After the critical period has passed, the horse can be gradually switched to a regular feeding schedule of oat, grass or alfalfa hay and concentrated feed to put the weight back on.” Also vital to a successful refeeding program, Stull feels, is deworming and the correction of any dental problems.
Under the expert care of Drs. Stull, Witham and Rodiek, and with assistance from the veterinary students, the remaining 19 horses thrived. By the end of the 10-day testing period, they showed marked improvement and continued to do well.
It took more than three months for the group to regain normal body weights (full rehabilitation typically takes three to five months). Once the horses had stabilized, they were taken to their new home—a recreational ranch in northern California, where they carry guests of the ranch on trail rides through the scenic countryside. The horses are maintained on a schedule of limited strenuous activity and plenty of rest and relaxation. They receive quality feed, have equine companions, and most important, are monitored by knowledgeable and experienced horse guardians. The ranch management and residents alike are sensitive to the herd’s history, and take a particular interest in their continued well-being.
Six months after the commencement of the study, Stull was happy to report, “the horses are healthy, energetic and round—some very round—and their conformation is much more proportioned. Instead of depressed, neutral personalities, they display the normal array of personality traits associated with horses: sassy, playful, kind, inquisitive and temperamental.”
Stull refers to the herd’s new home as a “horse haven,” and is thankful that each equine member of the study found a place there. As she puts it, “It helps to balance the unfortunate circumstances they encountered early in their journey.”
Pamela M. Richardson has a degree in equine management. She writes about horses from her home in Framingham, Massachusetts.
© 2002 ASPCA
ASPCA Animal Watch – Summer 2002