By Dr. Kelsey Jurek
For many horse owners, the fall and spring may bring more than just a weather change. It’s during these times of the year that equine laminitis cases tend to spike.
Equine laminitis is a condition of the horse's feet that results from a disruption of blood flow to the laminae, which is the structure that secures bone and soft tissue to the hoof wall.
“When laminitis occurs, inflammation causes the bond between the hoof wall and laminae to weaken, leading to separation of these structures,” said Dr. Kelsey Jurek, large animal emergency clinician at the Oklahoma State University College of Veterinary Medicine. “From there, the coffin bone can rotate within the hoof capsule or can displace downward. Eventually, the bone can become so severely displaced that it penetrates the sole of the hoof.”
The term "founder" is often used to describe the process of chronic laminitis that causes rotation of the coffin bone, while acute laminitis is used to describe sudden inflammatory attacks that cause severe pain and inflammation of the laminae.
Some horses are at a higher risk of developing laminitis, including:
- Overweight and/or very heavy horses
- Horses who are fed large amounts of carbohydrate-rich meals
- Older horses with Cushing's Disease
- Certain breeds such as ponies, miniature horses, donkeys, Morgans and gaited horses (Rocky Mountain Horse, Missouri Fox Trotting Horse, etc.)
- Horses who had previous episodes of laminitis
So, what about fall and spring can cause these flare ups?
“We tend to see laminitis cases flare up in the spring and the fall because the nonstructural carbohydrate (simple sugars, starches and fructans) content of pasture grasses is highest during these times of the year,” Jurek said. “For at-risk horses, the elevated sugar levels are enough to cause metabolic disturbances and lead to the inflammatory response that causes development of laminitis.”
The management of horses with a predisposition to laminitis is key to preventing the condition. Horses should be maintained on a modified diet that provides adequate nutrition based on forage that is low in carbohydrates. Grain and other sources of excessive sugar/carbohydrates should be avoided. In addition, avoid grazing at-risk horses on lush pastures (especially between late morning and late afternoon hours) and introduce all horses to pasture slowly and gradually in the springtime or anytime the pasture suddenly greens up.
“Recognizing when horses are over-conditioned, investigating potential metabolic disorders and working with your veterinarian to develop a safe weight loss plan will help prevent the development of laminitis in an otherwise healthy horse,” Jurek said. “A good health-maintenance schedule is also important, including routine hoof care, parasite control and vaccinations.”
Owners who may be concerned about their horse developing laminitis should be on the lookout for signs of both acute and chronic laminitis.
Signs of acute laminitis:
- Shifting lameness when standing and lameness when the horse is turned in a circle
- Heat in the foot and increased digital pulses (palpable on either side of the sesamoid bones at the level of the fetlock)
- Pain in the toe region when pressure is applied
- Reluctance to walk and a very stiff/hesitant gait
- A "sawhorse" stance in which the horse will rock back on its haunches and place its front feet stretched out in front of them to alleviate pressure on the toes
Signs of chronic laminitis:
- Rings in the hoof wall that become wider as they run from toe to heel
- Recurring abscesses, bruised soles, and a widened white line ("seedy toe")
- Flat feet/soles
- Dished hooves that resemble slippers (due to uneven hoof growth over time)
- Signs of metabolic disorders include a thick, cresty neck; abnormal fatty deposits behind the shoulders, on the tailhead, and over the ribs; and being an "easy keeper" that maintains or gains weight without a lot of nutritional support
- Radiographic evidence of rotation or sinking of the coffin bone
Any horse showing signs of laminitis should be taken off of pasture and evaluated by a veterinarian to determine an appropriate treatment plan. Laminitis is treated differently depending on whether it is acute or chronic and the severity of the laminitic episode. Regardless of the cause, early diagnosis and treatment of laminitis gives the horse the best chance at recovery.
If you are concerned your horse may be suffering from equine laminitis, contact your veterinarian.
Source : okstate.edu