2003 Aaep Annual Convention Review

By Dave Sauter, DVM
Kulshan Veterinary Hospital

The American Association of Equine Practitioners was founded in 1954 and is actively involved in research and continuing education in the equine veterinary profession and horse industry. There are currently over 7000 members of the AAEP worldwide. The AAEP held its 49th Annual Convention in New Orleans just before Thanksgiving, November 21 – 25. This is the world’s largest continuing education meeting devoted to equine veterinary medicine. Over 3000 veterinarians, veterinary technicians, and veterinary students attended this year’s convention. Most of the attendees were from the United States but many other countries were represented. There were over 6000 total attendees, including those at the annual Horseman’s Day sessions. The convention offered over 80 scientific and professional development sessions over the 4-day meeting. Additional hands-on workshops were offered on subjects such as dentistry, ultrasonography, emergency preparedness, and hoof surgery. Additionally, there was a trade show with over 400 exhibitors.

The AAEP convention this year was very well organized and provided practitioners with a wealth of information. Here are just a few of the highlights:

• Dr. Christopher Pollitt, representing the Australian Equine Laminitis Research Unit at the University of Queensland in Brisbane, Australia reviewed their research on laminitis over the past five years. This research is uncovering the disease mechanisms of laminitis at a molecular level. They have discovered two basic mechanisms that result in separation of the lamella of the hoof. One mechanism involves an over-activation of MMP enzymes. The MMP enzymes normally regulate hoof wall growth. Over-activation of MMP enzymes can be caused by various “triggering factors” released by various diseases, such as grass-founder and severe infections (pleural pneumonia, diarrhea, retained placenta). Another mechanism for laminitis has to do with the discovery that the laminae of the hoof are very dependent on glucose for energy. Any serious disruption in the delivery or utilization of glucose to the lamellae can result in separation. That may explain why horses with Cushing’s disease often have problems with chronic recurring laminitis. This research is expanding our knowledge of laminitis and will lead to improved treatment and prevention of this devastating disease.
• Dr. Steven O’Grady presented an excellent talk on managing chronic laminitis. He emphasized the importance of restoring the alignment of the coffin bone relative to the ground. He described a method for trimming and shoeing to achieve realignment, resulting in improved weight bearing of the coffin bone and decreased tension on the deep digital flexor tendon. His method utilizes composites enabling the shoe to be glued on, hence less traumatic to the foot than traditional nailing.
• Magnetic Resonance Imaging (MRI) is increasing our understanding of heel pain in horses. Dr. Robert Schneider at Washington State University reviewed MRI’s on over 150 cases over the past five years. MRI is enabling specific diagnoses of soft tissue, articular, and navicular bone lesions. Technology such as this will improve the precision of diagnosis of heel pain and hopefully lead to improved treatments.
• Neurology was another area of focus. West Nile Virus was the topic of several presenters. Dr. Julia Wilson from the University of Minnesota presented data showing increasing evidence of residual adverse effects in survivors of the disease. Common changes noted were gait and behavioral abnormalities. This is in contrast to what has been reported with West Nile Virus disease in Europe.
• Dr. Maureen Long from the University of Florida presented data demonstrating a significant level of subclinical infection with West Nile Virus. Subclinical infection refers to infection without signs (symptoms) of disease. This is important to consider when confronted with a neurological case and interpreting laboratory results. Other causes of neurological disease may need to be considered even if the lab test is positive for West Nile.
• There have been a few surprises with the spread of the West Nile Virus this year. The number of equine cases went down from 15,257 in 2002 to 4,426 this year so far. However, the number of human cases went up considerably and actually exceeded the number of equine cases. The number of human cases in 2002 was 4156 and this year there have been 8694 so far, with 2477 in Colorado, 1760 in Nebraska, and 1013 in South Dakota alone. Perhaps this has something to do with fact that the equine vaccine is effective and no human vaccine exists. Another surprise is that the disease did not extend to the far west as much as expected.
• Dr. Pamela Wilkins from New Bolton Center, University of Pennsylvania presented data on the experimental use of Acyclovir, an anti-viral drug, in horses suffering from herpes virus (Rhino) neurological disease. This disease is caused by a strain of the herpes virus that has an affinity for nerve tissue. This disease can result in significant mortality and is a contagious disease. Prior therapy has been limited to supportive care and anti-inflammatory treatments, not unlike human viral diseases. Experimental use of Acyclovir in this study showed potential as a useful therapy for this disease and it will be interesting to see more studies on this subject.
• Dr. A. M. Merritt from the University of Florida gave a wonderful lecture on the equine stomach. He began his research 30 years ago. This research is helping us understand stomach problems in the horse, especially the now known common problem with gastric ulcers. One highlight of his presentation focused on the cause of ulcers in horses in training. His studies have shown that there is normally a dramatic acid gradient in the equine stomach, with much more acid located at the lowest point. With increased abdominal pressure, particularly with training, there is a mechanical effect of pushing the acid up into higher areas of the stomach, which do not tolerate acid. This in effect is even greater when training is done on an empty stomach. Hopefully this type of research will lead to specific recommendations on feeding and training management.
• On the practical side, Dr. Schott from Michigan State University did a study to see if a strategy to increase voluntary drinking after exercise could be devised. He concluded that there were no detrimental effects to allowing access to water immediately after exercise. He also concluded that providing a salt water solution (30 grams of table salt per gallon of water) as the initial water after exercise resulted in greater water consumption during the first hour after exercise, provided plain water is offered soon after the salt water.

These highlights just scratch the surface on all of the scientific information and exchange of ideas that takes place at these events. AAEP has a section of the web site devoted to horse owners: www.aaep.org