Do you have a full-figured mare that practically plumps up just by looking at green pasture? Have you owned a beer-belly gelding that would rather snack and watch the equine version of Sunday football than get out for a bracing walk? You're not alone.
Although the 1998 National Animal Health Monitoring System survey reported the prevalence of overweight or obese horses to be only 5%, a 2008 Virginia-Maryland Regional College of Veterinary Medicine study suggests that obesity might be grossly underreported: Researchers found 51% of the horses sampled had a body condition score (BCS) greater than 6, including 19% with scores of 8 to 9. Normal BCS is 4-6 out of 9. A subsequent study at North Carolina State University showed 20% of horses were obese. While the incidence wasn't as high as in the Virginia study, equine obesity is still a problem.
As with humans, underexercising, overeating, and high-cal foods are the primary culprits for that ever-increasing girth. Genetics is another factor: Some breeds, breed types, and individuals retain or gain pounds on the same diet and exercise routine that keep their stablemates trim. For example, draft breed weanlings only need about 80% of the calories that Thoroughbreds or Standardbreds require.
Regardless, the recipe for keeping pounds off the plump-prone pony or for shedding excess weight is the same for horses as it is humans: Fewer calories, more exercise.
Since your hefty horse isn't likely to voluntarily hit the gym anytime soon or turn his nose up at the sweet feed, it's up to you to safely and effectively manage or reduce your easy keeper's weight.
For Weight Loss
Easing pounds off your horse is a simple premise: If your horse is on grain, cut it out. If he's eating hay, reduce the amount you feed and/or switch types. If he's on pasture, reduce grazing time. To avoid developing stomach ulcers or vices such as wood chewing, stall walking, weaving, and so forth, make gradual reductions in portions, feed smaller amounts more frequently, increase pasture time, and break up feeding/grazing time into small blocks throughout the day. Make sure your horse always has access to a salt block and water.
In addition, increase your horse's exercise for more calorie burn-off. Veterinarians have said they cannot emphasize enough the importance of exercise: you can restrict feed and calorie intake only so much, but you can increase the difference between calorie intake and calorie expenditure markedly with exercise. In obese people exercise helps preserve lean body mass more than diet alone.
Be creative about increasing the activity of your "couch potato" horses: Put them in a dry lot where the water and food and resting places are far apart. Put them with a more active horse that will pester them and increase their physical activity. Put hay in several locations so they have to move from place to place to find it. Finally, put the hay in a container that makes it more difficult for horses to consume the hay (i.e., a hay rack or net with small openings). See the sidebar on page 56 for more information on maximizing exercise.
Grains "Eliminate all grain from the diet," states Sarah L. Ralston, VMD, PhD, Dipl. ACVN (American College of Veterinary Nutrition), an associate professor in the Department of Animal Sciences at Rutgers University. "They don't need the calories." Instead, replace grain concentrates with a pound of timothy/alfalfa hay cubes at feeding time. "It gives the horses something to munch on."
Hay and pasture "Easy keeper horses on high-quality pastures often become overweight or obese even without additional grain or concentrate," notes Iveta Becvarova, DVM, Dipl. ACVN, a clinical nutritionist/clinical assistant professor at the Virginia-Maryland Regional College of Veterinary Medicine.
One contributing factor might be the grass itself. First, some grasses in selected regions of the country are naturally more lush and calorie-rich. Furthermore, many pasture forages were created to have higher sugar and calorie contents to increase weight gain in beef cattle and other food animals; this is good for growing heifers, but it's not so good for horses.
Of course there are horse owners with a poorer quality, lower-calorie hay or pasture, and still their horses aren't hurting for groceries.
Either way, the first step in planning your horse's weight loss program should be to learn precisely what you're feeding him. Says Becvarova, "The objective of a weight loss diet is to cut down on calories, not on the absolute amount of nutrients that your horse needs."
Have your horse's forage analyzed to identify calorie amounts and to ascertain excess or insufficient amounts of essential nutrients. Then adjust the feeding protocol accordingly by switching to a lower- calorie hay and/or limiting grazing time or hay portions. "I usually start by restricting current caloric intake by 20%, then monitor monthly the horse's body weight using a calibrated weight tape," says Becvarova. "An experienced nutritionist can help the client with this assessment."
Switching to a more mature, higher fiber (less-digestible) grass hay rather than reducing portions/grazing time is usually the best first option, as this allows the horse to continue to enjoy a longer munch time. "The dry matter intake should ideally be at least 1.5% of the horse's ideal body weight," says Becvarova.
If you do need to shorten grazing time, start out by limiting pasture time by 50%, and even to the morning hours only, advises Ralston. "Morning is the best time for grazing because that's when grasses are at their lowest nutritional and calorie value: Grass accumulates sugars during the course of the day."
In the afternoon either put a grazing muzzle on him (which allows him to drink, but significantly decreases his pasture intake), make afternoon pasture turnouts shorter, or put him in a dry lot. If he's in a dry lot, help satisfy his chew requirements by providing small amounts of mature, less-digestible hay periodically throughout the rest of the day.
"If the hay is not good quality (i.e., it's overly mature grass hay), mix recommended amounts of a balanced vitamin/mineral supplement into one-quarter pound of oats or water-soaked hay cubes to ensure nutrient requirements are met," advises Ralston. "If the haircoat starts to lose condition, a protein supplement may also be needed. Soybean meal, one-quarter to one-half cup per feeding, provides good-quality protein without adding a lot of calories."
Take care that you don't overdo it when reducing your horse's caloric intake. "Horses are designed to eat 12 hours a day," states Ralston. "Wood chewing and stomach ulcers are signs that the horse has inadequate dry matter intake. If these problems appear it is a sign that the horse should be changed to a less-energy-dense and higher-fiber forage that allows the horse to eat more."
After these adjustments you should start to see some weight loss in about two weeks. Monitor changes by rechecking body weight and body condition score every month, adjusting the ration if necessary, Becvarova recommends. The caloric intake should be adjusted if the weight loss is too fast or too slow. Ask your veterinarian if you are unsure about your horse's rate of weight loss. Furthermore, as his body weight decreases, so does the amount of calories needed to maintain the desired weight loss rate.
The first sign that you need to adjust the diet is when you can't detect weight loss between the rechecks before the ideal body weight is achieved. "Keep records of monthly body weights and body condition score, adjusting the caloric intake on monthly basis, depending on the weight loss progress," Becvarova says. "Systematic monitoring is critical and is the only way to successfully manage overweight and obese horses. If possible, increased duration and intensity of exercise greatly facilitates weight loss in these cases."
After your horse reaches an ideal body condition of 4-6 out of 9, slightly increase the amount of hay, cubes, or grazing time to stop the weight loss. "You don't want them to continually lose weight," explains Ralston. "Gradually increase the amount of grass hay to the point where the horse is no longer losing weight, again feeding several small meals throughout the day." This will be your horse's maintenance protocol, although adjustments might be necessary depending upon the season, level of physical activity, lushness of pasture, etc.
Grazing muzzles still might be necessary for horses and especially ponies during the growing season. You should continue to offer salt blocks and water free choice.
For those easy keepers that are at their ideal weight or reach it after a weight loss regimen, keep them that way through a weight-sensitive protocol. Similar to the weight loss program, you should:
- Feed dry matter equivalent to at least 1.5% of the horse's weight "If a low- calorie, increased-fiber balanced ration is fed, there is no need for decreasing the feeding frequency," says Becvarova.
- Make hay and pasture--not grain--the base of your horse's diet Grains and grain-based concentrates are high in calories and digestible carbohydrates.
- Feed higher-fiber (less-digestible) hay Explains Becvarova, "Easy keepers typically don't require prime-quality hays (leafy legume forages such as clover and alfalfa or grass hays harvested at their peak of nutrition). Feed more mature hays that have increased fiber content. Increased fiber content has poorer digestibility, which helps to limit calories taken in while permitting prolonged feeding times."
- Know what you're feeding "Hays differ in the quality and quantity of nutrients, depending on the climate, maturity, soil type, and fertilization," she says. "I recommend submitting a representative hay sample for analysis of nutrient makeup. Get the analysis prior to purchasing larger quantities to ensure the hay meets the needs of the horse or horses. Contact an experienced nutritionist to have the hay analysis assessed and the ration balanced."
- Feed accurately, based on the weight of the feed, not feed volume Use an accurate scale to weigh feeds.
- Limit grazing time in rich pastures by using a grazing muzzle or limiting pasture access Remember that in warm weather morning is the best turnout time for easy keepers because the sugar content is at its highest in the afternoons.
- Feed smaller meals more frequently to minimize the time a horse spends with an empty stomach This is important for preventing gastric ulcers and vices.
- If you need to add in a vitamin, mineral, and/or protein supplement, consult with a nutritionist He or she will help you find the best product to complement the nutritional quality of your hay.
"The bottom line for easy keepers is you don't have to feed them as much," Ralston says.
By regularly monitoring your horse's weight or body condition score, and by adjusting rations if your horse's weight starts creeping up--not after your horse reaches obesity--you can keep your easy keeper at his healthy weight.
About the Author
Marcia King is an award-winning freelance writer based in Ohio who specializes in equine, canine, and feline veterinary topics. She's schooled in hunt seat, dressage, and Western pleasure.
POLL: University Equine Hospitals