FAEP 2008 Symposium
Thirteen presenters took to the podium, covering lameness, reproduction, and medicine topics at the fourth annual Promoting Excellence Symposium of the Florida Association of Equine Practitioners (FAEP), held Sept. 25-27, 2008, in San Juan, Puerto Rico.
Noah Cohen, VMD, MPH, PhD, Dipl. ACVIM, professor of Large Animal Clinical Sciences at the Texas A&M University College of Veterinary Medicine & Biomedical Sciences, kicked things off with a discussion on evidence-based medicine, explaining how to critically appraise published studies on a topic and how this information fits into practice. The evidence-based theme carried over through much of the meeting.
Craig Roberts, DVM, 2008 FAEP president, said the theme arose from the August 2007 edition of the Veterinary Clinics of North America: Equine Practice book.
"We felt it would be an excellent grounding for our membership to raise their awareness of the factual data, or lack thereof in some fields of medicine, which guides our daily practice methodology," Roberts said.
Here are highlights from the meeting.
Laminitis: Cryotherapy Treatment
From a layman's perspective, cryotherapy (use of cold for treatment) for horses at risk of or just beginning the acute phase of laminitis just makes sense. The laminae are inflamed, the hooves are hot to the touch, so let's cool them down and keep them cold. Researchers get that, too. But there are still some questions on how this method works, and there are some issues when it comes to real-world applications.
Chris Pollitt, BVSc, PhD, head of the Australian Equine Laminitis Research Unit at the University of Queensland, shared some ideas on the function and uses of cryotherapy.
Pollitt said two factors in clinical trials have emerged as crucial to the success of this method: early intervention and duration of treatment. The earlier an at-risk horse can start cooling and the longer he can remain cooled seem to be paramount to the effectiveness of the treatment.
Pollitt said an at-risk horse should undergo cryotherapy as soon as possible--definitely before clinical signs of laminitis manifest. These can include heat in the feet, a bounding digital pulse, and favoring the affected limb, sometimes even "pointing" it in discomfort.
Trials using horses with laminitis induced just prior to and in the midst of therapy have demonstrated the method to be effective in preventing clinical signs and permanent damage. However, questions about whether cryotherapy can slow or halt the damage once it's started have not been answered.
In a horse with strong digital pulses, "If you use cryotherapy, you're chasing the shadow of the damage that's been done," Pollitt said. Exposed to cryotherapy, these horses might stabilize and not get worse, but the outcome mainly depends on what structural damage occurred.
As for duration of treatment, trials have shown that horses can tolerate cryotherapy over sustained periods. According to studies Pollitt cited, horses can stand in ice water for hours or days without the frostbite or other complications that make this approach dangerous for human patients.
"There's no real limit on the application of cryotherapy," Pollitt said, citing one study in which the horses remained in constant cryotherapy without damage for seven days. "I have no problem with leaving it on for as long as you think the horse is at risk from disease in other areas of its body."
In summary, the earlier you can intervene in a potential laminitis case, and the longer you can maintain treatment, the more likely you will succeed in preventing laminitis or reducing its damage.
New Weapons for Corneal Ulcers
"My job is to help horses see better, and to help you guys to help horses see better," said Dennis Brooks, DVM, PhD, Dipl. ACVO, a professor of ophthalmology at the University of Florida.
Brooks reviewed a variety of treatment and management strategies for corneal ulcers, with a focus on not only resolving the ulcer in each case, but maintaining the horse's vision.
A practitioner has a good chance of maintaining the horse's vision in the affected eye when faced with a variety of foes; new methods, such as amniotic grafts and serum, in concert with tried-and-true treatments, including antibiotics and atropine (the latter used to relieve pain and dilate the pupil) when indicated, make this possible.
Brooks expressed enthusiasm for the use of amnion--a material taken from the sac surrounding embryos that has antimicrobial, antifungal, and antiprotease (thwarting damaging enzymes) properties.
Amnion is a strong avascular (not supplied by blood vessels) material. Neutrophils and bacteria attack it instead of the ulcer, giving the eye a chance to heal. Brooks wants the amnion graft to stick for five to seven days, then fall off. His current goal is to develop a blood-based glue to attach these grafts in the standing horse.
"'This is going to change everything," Brooks said. "It already has."
The use of serum is another recent advance in equine ophthalmology. Produced by spinning down the patient's own blood, Brooks said serum is a relatively cheap option for reducing protease activity. He prefers not to refrigerate the serum, which he said has lasted and retained efficacy for eight days in trials. In a clinical setting he replaces the stock every week.
Another new development in ophthalmology is problematic, although it's been noted in multiple areas of equine medicine--resistance to medications. Brooks noted both fungal and bacterial resistance to treatments, meaning some treatments that worked as recently as two years ago simply aren't effective anymore, and "bugs" in different areas of the country are changing in different ways. He said there isn't one cookbook approach that will work everywhere, emphasizing the need for specific diagnostics, including culture, cytology, and deep corneal scrapings prior to treatment in order to target the specific trigger and initiate pinpointed treatment.
Some other points of interest from Brooks' talk on corneal ulcer care:
- The frequency and combination of treatments impact effectiveness. Some things can be used, or might even be more effective, in combination. Others should not be mixed. Some require a set number of treatments per day, and some should be given as often as the client can manage it.
- Stem cell treatment might be the next big thing.
In conclusion, he expressed hope that practitioners these days are better equipped to fight eye problems in horses than they have been in the past. "Things are changing for the better," he said. "It's taken a long time, but we're finally making progress."
Rhodococcus equi is a bacterium and a major cause of pneumonia in foals between 3 weeks and 5 months of age. Cohen and Steeve Giguére, DVM, PhD, Dipl. ACVIM, of the University of Florida's College of Veterinary Medicine, gave a presentation on R. equi.
In North America the pathogenic (disease-causing) form of R. equi is endemic on some farms, and approximately 10-20% of foals on endemic farms develop clinical signs of pneumonia. The speakers walked the practitioners through the diagnosis, pathogenesis (the origination and development of disease), immunity, epidemiology (the sum of the factors controlling the presence or absence of a disease or pathogen), therapy, and control of the disease. The final chapter of their evidence-based marathon session focused on prevention.
Cohen noted that R. equi can be found on farms with or without the disease the bacterium causes. For control and prevention purposes, the farm itself is the patient, and practitioners need to tailor their strategies to fit the needs of the farm and its management.
Farm management and maintenance appear to have an impact on infection rates. Cohen noted that some researchers suggest keeping foals and mares outdoors to reduce the risk. However, beyond that, R. equi presents a unique challenge in that management strategies that prevent other infections on large farms seem to have no effect against R. equi.
Researchers from Texas A&M recently examined chemoprophylaxis as a method to prevent clinical disease. In one study researchers found they could prevent disease by administering the antimicrobial drug azithromycin during foals' first two weeks of life. In the study 5.3% of treated foals developed disease, compared to 20.8% in the control (untreated) population. (See article #11715 on TheHorse.com for more about this study.) Cohen noted that while this study is important as a proof-of-concept, he and his colleagues do not at this point recommend attempting prophylactic treatment with this antibiotic, as widespread use of this drug could promote resistance. Azithromycin is important for treating human as well as veterinary infections, so there are public health considerations.
One strategy to prevent infection is the use of hyperimmune plasma; however, this is by no means a perfect approach. Cohen said it "does something to reduce the incidence of disease in most circumstances, but it's by no means uniformly effective and it does carry some risks."
Most studies going back to 1989 do show a reduction in R. equi in hyperimmune plasma-treated foals, but these studies used different doses, numbers of treatments, and foals of different ages at time of administration, so questions remain as to whether the conclusions are accurate when such variables change in a clinical setting. In one study treated foals had a higher incidence of disease than their untreated counterparts. Plasma also brings the risk of adverse reactions (possibly including serum hepatitis).
The timetable practitioners are working with--treating neonates exposed within days after birth--presents a major challenge for a vaccine to be effective, although much work is being done in this area.
So what can be done?
For now, carry on with what works on a farm-by-farm basis and know that researchers are working on some exciting new prospects--namely gallium maltolate, a metal-based drug, and new strategies for vaccines. Results of a trial evaluating gallium maltolate for chemoprophylaxis should be available later in 2009.
From the racetrack to the eventing course, catastrophic injuries at equine competitions just seemed to keep happening in 2008. And with them came a tangible shift in public perception and mainstream media coverage of these events.
Veterinarians at the symposium discussed the current challenges facing equine sports and associated practitioners in a special session led by 2008 AAEP President Eleanor Green, DVM, Dipl. ACVIM, ABVP, and Larry Bramlage, DVM, MS, Dipl. ACVS. Bramlage is one of the familiar faces of the AAEP's On Call Program, through which media-trained veterinarians are available to comment on equine health issues at major events, such as the Triple Crown races.
Participants discussed public perception, horse owner education, working with the media, and efforts to improve equine welfare that are already under way.
This is just a portion of the information presented during the symposium. "The goal of the FAEP is always to present quality and depth of information on each of the subjects it covers," Roberts said.
The next the Florida Association of Equine Practitioners Promoting Excellence Symposium will be held Oct. 1-3 on Marco Island, Fla. Veterinarians from all states are welcome to attend. For more information on this and other continuing education options through this group, see www.FAEP.net.
About the Author
Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care.
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