The Horse:Your Guide To Equine Health Care provides monthly equine health care information to horse owners, breeders, veterinarians, barn/farm managers, trainer/riding instructors, and others involved in the hands-on care of the horse.
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50 TheHorse.com THE HORSE March 2018 STEP BY STEP HEATHER SMITH THOMAS TheHorse.com/Step-By-Step I t's morning turnout time, and your easy-keeping Welsh pony isn't quite himself. He hesitates before stepping out of his well-bedded stall onto the hard concrete, so you figure he's a little foot- sore. After a few days of stall rest and some veterinarian-prescribed Bute, he's sound. You chalk it up to a foot bruise. In reality, your horse could have just suffered a small bout of laminitis (inflam- mation of the laminae/lamellae—the interlocking leaflike tissues attaching the hoof wall to the coffin bone) tied to an as- yet undiagnosed case of equine metabolic syndrome (EMS). And it might not have been his first. "The problem with the endocrine case is that there is cumulative damage over time—often for many years," says Amy Rucker, DVM, an ambulatory veterinar- ian in Central Missouri who has a special interest in equine feet. "The first time the owner recognizes that the horse has lami- nitis might not be the first time the horse had the problem." So how can you recognize when a horse is at risk for developing EMS- related laminitis? And what can you do to either prevent or manage it so he stays sound? Let's find out. Pinpointing the Problem The terms equine metabolic syndrome and pituitary pars intermedia dysfunction (PPID, or equine Cushing's disease) often go hand-in-hand. And they're frequently accompanied by conditions such as laminitis and insulin dysregulation (ID, which is either hyperinsulinemia, excess levels of insulin in the blood, or insulin resistance, a decrease in tissue sensitiv- ity to insulin). So what's the connection between all these words? Equine metabolic syndrome and PPID are both endocrine disorders that can negatively affect insulin levels and lead to laminitis. Horses and ponies with EMS produce too much insulin in response to feed and are often (but not always) overweight. Pituitary pars intermedia dysfunction affects horses and ponies as they age and can have similar effects on insulin regulation. Both conditions develop so gradually that by the time owners notice and veterinarians diagnose them, many horses are already suffering from the effects of laminitis. "The problem we often see with endocrine-related laminitis is that it often develops insidiously and quietly," says Andrew van Eps BVSc, PhD, MACVSc, Dipl. ACVIM, associate professor of equine musculoskeletal research at the University of Pennsylvania's School of Veterinary Medicine, in Kennett Square. "By the time the owners realize there is a problem, they are often shocked at how advanced it is before the horse actually shows any lameness or outward abnormality." For this reason, he says, owners of horses at a higher risk of endocrine- related laminitis (e.g., ponies, Morgans, Arabians, and Warmbloods; horses that are obese and/or have regional fat deposits) should have their veterinarians perform initial blood tests to screen for ID (and PPID in older animals), followed by regular repeat testing. Farriers can also help identify at-risk horses before laminitis sets in. "As farri- ers, we see the horse more often than the veterinarian," says Travis Burns, lecturer and farrier at the Virginia Maryland Col- lege of Veterinary Medicine at Virginia Tech, in Blacksburg. "If a horse starts to gain weight or become a little tender-foot- ed, we can help the owner realize there is a problem. If the horse becomes insulin- resistant or stays in a chronic state of inflammation, the feet will drift too far in the wrong direction and we won't be able to stop the damage." Look for subtle changes in weight, body condition, and hooves, as well as signs of a metabolic issue, such as a cresty neck or a thickened hair coat that doesn't shed normally. Hoof Care for EMS Horses From the founder-prone chubby pony to the chronic endocrine-related laminitis case, here's how to keep your EMS horse comfortable Subtle physical signs that a horse is at risk of or developing laminitis include a stretched white line (left) or growth rings that are wider at the heel than at the toe (right). COURTESY TRAVIS BURNS/DR. R. SCOTT PLEASANT