Laminitis--a disease that strikes fear into the hearts of horse people everywhere--was the primary focus of the Second International Equine Conference on Laminitis and Diseases of the Foot, held Nov. 10-11 in West Palm Beach, Fla. This conference is held every other year and sponsored in large part by John K. and Marianne Castle, whose Appaloosa Spot had chronic laminitis secondary to Equine Cushing’s Disease (ECH) and died from colic several years ago. There also are several other private and corporate sponsors.
Teamwork between veterinarians, farriers, researchers, and horse owners to solve the mysteries of laminitis was the main theme of the opening remarks by course director James A. Orsini, DVM, Dipl. ACVS, associate professor of surgery at the University of Pennsylvania's New Bolton Center in Kennett Square, Penn.
For example, he said, "The more researchers understand about the work of the veterinarian and farrier, the more researchers can develop research that these professionals can use."
He also discussed the importance of proper supportive care, noting, "As much as we advance in science and technology, we can never afford to ignore the value of compassionate care to maximize the horse's quality of life. When we work with our hearts along with our expanded knowledge, we provide better care.
"We need a long-term, systematic approach to solve the problem of laminitis. We must go at it from several different directions," he concluded. With research from all over the country and as far away as Australia presented at this conference, there certainly seems to be a good start.
Following his opening remarks, Orsini presented a "Top Ten List" of the most significant topics (selected via attendee feedback) from the first conference, held in 2001.
Top Ten Things We Learned About Laminitis
10. Once laminitis has occurred, later episodes of laminitis can be caused by relatively minor stresses.
- Careful management reduces risk of recurrent acute episodes.
- Gradual weight loss is beneficial to overweight horses.
- Shoeing and foot care are essential.
- Level of exercise is dependent on the severity of the problem.
9. Mechanical forces acting of the hoof can lead to structural collapse of the hoof wall.
- A poorly attached coffin bone can be driven down under the horse's weight, tearing arteries and veins; crushing the corium of the sole and coronet; and causing severe pain and lameness.
- When loaded, the deep digital flexor tendon can worsen rotation of the coffin bone.
8. Not all cases of chronic laminitis are catastrophic or life-threatening.
- • The predominant problem is secondary complications such as hoof cracks, wall separation, abscess formation (localized or abscesses that undermine large areas of the wall).
7. "Obesity and laminitis syndrome" is responsible for many cases of laminitis previously blamed on equine Cushing's disease (ECD) or hypothyroidism.
- • Diagnosis is made by clinical signs, age of the horse, and laboratory testing.
- • Glucose and insulin might be high in both ECD and obesity and laminitis syndrome.
- • Plasma thyroid hormones might be abnormally low with obesity and laminitis syndrome. (The horse appears to be hypothyroid, but this is an effect, not the cause.)
- • Obesity and laminitis syndrome seems to be caused by abnormally low levels of activity of 11-beta-hydroxysteroid dehydrogenase, which regulates steroidal activity within the tissues.
6. Maintaining submural blood supply during the developmental phase of laminitis with calcium channel blockers and/or rheologic agents (drugs that deform matter such as red blood cells and thus improve blood flow) might reduce the severity of laminitis.
- A prolonged period of reduced blood supply is present before lameness.
- Lameness first appears during reperfusion of the foot.
- Digital perfusion increases after lameness is present.
5. The duration of laminitis is a risk factor for development of laminitis in the opposite limb.
- Horses which remain lame for greater than 18 days are at an increased risk for developing laminitis in the contralateral leg. Duration of lameness--not body weight--is a risk factor in the development of laminitis in the contralateral limb in the horse with unilateral lameness. (Note: Many attendees described their proactive efforts to support the opposite leg in such cases before any problems appeared, with the frequent result that no problems with this limb occurred.) Horses which develop this complication are more likely to be humanely destroyed than those that do not.
4. The severity of laminar damage in the horse with acute laminitis equals the severity of clinical signs and prognosis.
- Initial damage precedes clinical signs. Veterinarians and farriers come into the problem behind the curve, which is why it's so important to manage risk factors to avoid the problem in the first place.
- Many horses with acute laminitis are not treated unless clinical signs are severe.
- Reference: Introduction to the Pathophysiology of Acute/Developmental Laminitis, by Gary M. Baxter.
3. Due to the compromised laminar interface, the horse with acute laminitis should not be walked or trailered.
- They are so fragile at this point that it's best not to stress them with movement. The only thing you're going to do is make things worse, and maybe kick a borderline case over the edge.
- Supportive therapy reduces laminar stress and further injury.
- Increased stress associated with movement can be decreased with absolute stall rest.
- Reference: Treatment of Acute Laminitis by Andrew H. Parks.
2. Proper sole support and stall rest are two of the most important factors in the successful treatment of laminitis.
- Use other parts of the sole surface of the foot to bear weight, and stress on the wall decreases.
- Achieve this by increasing ground contact between the sole and frog.
- Rigid foot casts are not recommended as they can impair circulation.
- Reference: Treatment of Acute Laminitis by Andrew H. Parks.
1. Appropriate treatment in the acute phase can make the difference between soundness and lameness, and life and death.
- During the acute phase, medical treatment is aimed at reducing or neutralizing the pathophysiologic changes, reducing stress-induced separation of the diseased laminae, and decreasing pain to reduce the sequelae (results of) pain. This is a time when the horse should be treated like it's an emergency, possibly with painkillers, anti-inflammatory medication, and maybe a sedative.
About the Author
Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.