Keeping the Big Guys Healthy
By D.J. Carey Lyons • Jan 20, 2014 • Article #33204
The Budweiser Clydesdales, which number 170, require custom care.
Photo: Courtesy Anheuser-Busch
They were bred to be workhorses: to pull plows, sledges, and wagons loaded with goods, equipment, or artillery. Draft breeds helped move the factory output of the Industrial Revolution, then the caissons and gun carriages of both sides in World War I. By the time peace returned, they were losing their civilian jobs to the “horseless carriage.”
But their towering stature (some are upwards of 19 or 20 hands tall) and their hold on people’s imaginations secured their presence among us. Today, a number of active draft breed registries support breeders producing and competitions showcasing these animals, and draft horse hitches remain sure crowd-pleasers at any parade.
For instance, the Budweiser Clydesdales made their public debut in 1933, delivering a case of beer to the White House to mark Prohibition’s end. Since then, they’ve been regulars at events around the country. Now numbering 170, they’re stabled at several facilities around the United States and headquartered in St. Louis, Mo.
The University of Tennessee (UT) Veterinary Medical Center has overseen the Clydesdales’ health for 30 years. These days, UT associate professor of equine surgery Steve Adair, MS, DVM, Dipl. ACVS, ACVSMR, is their herd health consultant—a job that takes him all over the country. He says that although a few health issues—mostly size and/or work-related—show up more in draft breeds, “from a general-health standpoint they aren’t very different from any other horse.” He’ll guide our look at these equine giants, starting from the ground up.
Supporting roughly a ton of muscle and bone, draft horse feet are—literally and figuratively—under a lot of pressure. Conformation, cleanliness, and weight all factor into these structures’ health and function.
Draft horses might wear scotch-bottomed shoes and pads to help support their body weight.
Photo: Courtesy Anheuser-Busch
Foot conformation These issues are usually related to genetics, Adair says. “Some individuals or breeds will have an upright foot with well-defined heels,” he explains. “Others have flat ‘pancake’ feet that tend to splay out under the weight they’re carrying and that have little-to-no heel, creating stresses (on the frog and sensitive structures beneath) that can lead to lameness.” Adair says one way to improve the latter horses’ base of support is with scotch-bottomed shoes, characterized by an edge that slopes outward from the hoof surface to the ground (creating more surface area on the shoe for weight-bearing). Heart bar shoes that support the frog might also help. Some owners elect to fit leather, plastic, or rubber pads between shoe and foot to cushion the impact of flat-soled feet hitting the ground.
Hoof hygiene Inadequate hoof cleaning raises the risk of two foot problems developing: thrush, an anaerobic bacterial infection of the frog that creates a foul-smelling discharge; and canker, a chronic proliferation of the frog and sole also presumably caused by anaerobic bacteria. Draft horses can be reluctant to lift their feet, which is one disincentive to thorough foot hygiene. Then there are the hoof pads described. These, Adair says, “can trap debris and moisture—and you can’t adequately clean out the bottoms of feet with pads on them.” He says soft acrylic medicated sole packing can prevent debris from getting caught and infection taking hold.
Moisture can also build under feathers, the long hairs on the backs of many draft breeds’ legs. Skin that stays damp can become irritated, creating an opportunity for dermatitis in the pastern region—or scratches—to develop. In many cases scratches is secondary to infestation by chorioptic mites, Adair says, and horses that spend hours outside in a wet environment are especially vulnerable to it.
Laminitis risk “For a draft horse, which can weigh up to 2,300 pounds, a laminitic crisis (inflammation of the laminae, which connect the hoof wall to the coffin bone) tends to be worse simply because of weight,” Adair notes. “It’s a biomechanical thing: If the laminae are compromised, the effect of that weight creates a graver problem. Are draft horses more prone to developing laminitis? No. But in the right set of circumstances—a grain overload, endometritis (inflammation of the innermost lining of the uterus), or some systemic illness causing a horse to become laminitic—the resulting damage tends to be more severe.”
Getting a Leg Up
University of Tennessee associate professor of equine surgery Steve Adair, MS, DVM, Dipl. ACVS, ACVSMR, notes that draft horses can be stubborn about having their legs picked up, so it's quite common for farriers in the industry to use shoeing stocks - a set of stocks the horse walks into that uses a weight-operated support stand to hold up on leg at a time.
"The (Budweiser) Clydesdales don't need shoeing stocks; they've been trained from their early years to hold their legs up," Adair says. "But if you've got a lot of feet to pick up in a day, you back will be pretty sore by the end - so having shoeing stocks you can rest a foot in, and not have to hold up all that weight, is a big help."
D.J. Carey Lyons
Draft horses’ hocks and pasterns are the areas where arthritis issues most commonly develop, Adair says. “Bone spavin in lower hock joints and ringbone in pasterns both result from the wear and tear of work,” he says. “Additionally, rapidly growing, rapidly developing individuals in these large breeds are at some risk for developmental orthopedic disease, including osteochondrosis,” a disorder of growing cartilage that affects either the growth plate or the articular cartilage, in this case primarily in the hock area.
A gait-related issue draft horses display more frequently than light breeds is the neuromuscular disorder stringhalt. Horses with this chronic condition appear to snatch up a hind leg suddenly. Some veterinarians perform a surgical procedure that involves removing a section of one of the tendons crossing the outer portion of the hock to help treat the stringhalt.
Another problem that might occur more frequently in draft horses is chronic progressive lymphedema of the rear limb, commonly known as “big leg” and characterized by swelling from the foot all the way up to the stifle. It typically occurs when infection from a skin wound spreads to the lymphatic system. The condition causes severe pain and lameness in the affected limb, skin lesions, fever, and increased heart and respiratory rates.
“You can get the swelling down using anti-inflammatory drugs, antibiotics, cold hydrotherapy, exercise, and wraps,” Adair says. “But it may recur a few months later, and damage from the earlier attack—scar tissue and impairment of the lymphatic system’s drainage ability—may prevent the leg from going down as well as before. The problem tends to repeat, worsening each time. It can be career-limiting, though it’s usually not career-ending.”
As to why it seems to show up more commonly in drafts, Adair thinks feathers might be the answer: “The long hairs tend to trap moisture, and an abrasion or wound under them might not be as noticeable,” escaping detection and treatment.
Another condition Adair says occurs in draft breeds is shivers, a chronic nervous or neuromuscular syndrome typically affecting one or both hind limbs and the tail. “Shivers is characterized by periodic involuntary spasms of the muscles in the pelvic region, pelvic limbs, and tail,” he says. “At this time there is no effective treatment.”
Neck and Head Issues
“Because of the long length of their necks,” Adair says, “draft breeds probably have a higher instance of laryngeal hemiplegia (larynx dysfunction that compromises a horse’s ability to breathe) than other horses. In other words they ‘roar,’ or make a noise during inhalation. Roaring tends not to be as performance-limiting for draft horses as for, say, a racehorse, but it can have some effect.”
As for dental care, it’s important that a veterinarian carefully check draft horses’ teeth, and float them if necessary, as part of an annual or semi-annual veterinary examination. A complicating factor, of course, is these horses’ height. “If a draft horse decides to raise its head, you pretty much have to go get a stepladder,” Adair says. “But for the most part, in my experience, they’re no more difficult than any other horse.”
“For years,” Adair says, “people have overfed draft horses, so they’ve tended to be obese. And, as in humans, obesity can lead to arthritic and foot issues.”
“You can have a 1,700-pound draft horse that is obese, and you can have a 2,200-pound draft horse that's a little on the thin side. ”
Dr. Steve Adair
Draft horses’ size can lead owners to believe they require far more feed than normal horses. “Certainly they need a daily ration of good-quality grass hay, or pasture, in an amount roughly equal to 2% of their body weight,” Adair says. “That’s the base. Then they might need a ration balancer—a vitamin/mineral supplement recommended by a veterinarian. Any feeding above that needs to be based on the type and level of work the horse is doing.”
Some horses, even when in work, need only grass hay and a ration balancer. Others require some type of concentrate to maintain weight and condition.
Because “you can have a 1,700-pound draft horse that is obese, and you can have a 2,200-pound draft horse that’s actually a little on the thin side,” Adair recommends assessing body condition score, not weight alone, to gauge whether a draft horse’s condition is appropriate.
“Look for areas of regional adiposity, or regional fat deposits,” he suggests, which can indicate equine metabolic syndrome (TheHorse.com/29993). “And many draft horses are easy keepers—or equine--metabolic-syndrome horses, to use the current term; they (practically) smell grain and gain weight. These individuals can also be prone to developing laminitis. The new low-starch, low-carb feeds we’re seeing are primarily directed toward decreasing such horses’ insulin resistance,” a reduction in a horse’s sensitivity to insulin that makes it harder for the fat, muscle, and liver cells to transport the glucose out of the bloodstream and store it as glycogen.
Personally, Adair says he prefers a draft horse to have a body condition score from 6-7 (on the 1-9 scale) to increase that animal’s longevity. “At this level they have the body mass to do the required work but they are not so heavy as to lead to other medical problems,” he explains.
This is another area where a draft horse’s potential for obesity can have negative effects. Regardless of breed, obese mares are more difficult to get in foal. And even if the mare’s weight is normal, “simply because of foal size there may be a slightly higher instance of dystocia—difficult birthing,” Adair says.
Other reproductive issues include lower fertility rates, greater chances of twins, retained placentas, and difficulty rebreeding. And if you do breed draft horses, bear in mind their predisposition toward several genetic diseases, most commonly:
Junctional epidermolysis bullosa This recessive disease causes skin lesions to form over pressure points of the body in newborn Belgian foals (among other draft breeds) and results in large areas of skin loss. The condition is untreatable, and foals die within 24 hours to 14 days.
Polysaccharide storage myopathy (PSSM) This muscle disorder presents as muscle soreness, weakness, and tying-up in some draft horses and crosses. Owners should manage affected horses by providing regular turnout, a gradually increasing exercise schedule that becomes a regular routine, and a low-starch/high-fat diet.
Other Health Considerations
Exercise For draft horses, as for any horse, Adair is a fan of 24/7 turnout. Providing that much time out can be difficult but, for example, “when the (Budweiser) Clydesdales are on the road, they get taken out and walked several times every day if they’re not showing. Schedule and weather permitting, they’re also hitched up to a sled for exercise on their off days.”
Keeping any horse stalled 23 or 24 hours a day can be detrimental, as equids are made to graze and browse continually. To support their gastrointestinal and musculoskeletal health, they need to get out and move around.
Medication “There are some drugs that we give draft horses on a ‘by weight’ basis: antibiotics and dewormers, for example,” Adair says. “But with sedatives and anti-inflammatories, we’ve found that they tend not to need as much. So the amount of sedative I give a 2,200-pound draft horse is about the same as what I’d give a 1,000 to 1,200-pound Quarter Horse.”
Surgery Adair says any type of major surgery on a draft horse is challenging because it involves putting them under general anesthesia, and there are potential complications associated with that. The most difficult aspect, he says, is ensuring adequate oxygen supply to muscles and tissues under the unaccustomed weight.
“When a draft horse is in lateral or dorsal recumbency, the blood flow to the muscle is decreased due to the sheer weight,” he explains. “When you couple this with the decrease in blood pressure that occurs as a result of the anesthetic drugs and the body position, you get poor perfusion of the muscles and myositis (muscle inflammation) can develop. Myositis can be very painful and lead to kidney failure.”
Life span A draft horse’s life expectancy depends on what he is used for and how hard. A horse that’s mostly running around the pasture and not in heavy work might live well into his 20s and early 30s, Adair says. For a horse with a light to moderate work life, “living into the late teens or early 20s would not be unexpected,” he says. “But with those individuals that really work for a living, the ones under loads every single day, joints and bones wear out sooner.”
Don’t let a draft horse’s size fool you into thinking he needs more groceries than your light-breed animals; don’t overfeed, and assess body condition score regularly to confirm that his rations suit his workload and that he’s maintaining good muscle. Be sure regular veterinary exams include a full oral checkup, careful skin inspection, and a good look at all four feet. Use daily grooming as an opportunity to catch common problems such as scratches, thrush, and canker. The earlier you spot a problem, the better your odds for correcting it and repairing the damage.