by: Nancy S. Loving, DVM
Endurance horses perform protracted exercise of up to 12 hours for a 50-mile event, and up to 24 hours for a 100-mile competition. Besides metabolic issues created by fluid depletion and electrolyte imbalances due to sweating during sustained performance, immune and respiratory challenges stemming from transport to the event are added concerns. At the 2008 American Association of Equine Practitioners convention, held Dec. 6-10 in San Diego, Calif., this author (Nancy Loving, DVM) presented on unique conditions associated with offering emergency care at endurance events.
Endurance rides are often held in wilderness areas without good road access, posing a challenge when trying to reach a horse in distress. A Treatment Veterinarian should be equipped with sufficient horsepower (vehicle, ATV, or horse) to reach a horse if it cannot be reached with a horse trailer and transported. Organizers should provide all veterinarians with a deployment schedule that identifies where each veterinarian is stationed throughout the event. They should also arrange transport trailers with competent drivers equipped with maps in advance, and people familiar with the area should accompany them.
Endurance horses are affected by the excitement created by numbers of horses moving down the trail. Upon entering the vet checks, horses are bombarded with stimulation from crew activities: continual heart rate checks, sponging, and removing tack. It is not always possible to identify a horse with problems until it is separated from the "herd" and offered time to eat, drink, and relax.
At national (American Endurance Ride Conference, AERC) and international (Fédération Equestre Internationale, FEI) endurance rides, a hierarchy of people must be in steady communication throughout the event--Ride Management (Organizing Committee), the Veterinary Judge (members of the Veterinary Commission), the Treatment Veterinarian, and at FEI rides the Veterinary Delegate and Ground Jury. Communication among these individuals is critical and can be accomplished by using cell phones or enlisting help from ham radio operators.
Besides addressing those horses needing acute treatment, the treatment veterinarian will examine every horse eliminated from the ride within the hour following elimination to ensure that a concern that seems to be musculoskeletal in nature is not a metabolic-related myositis (muscle inflammation--in most cases, tying-up). This exam also ensures that every horse is making progressive recovery and identifies those needing treatment.
Designated treatment area(s) should be located away from foot traffic or casual onlookers who could interfere with safe treatment. A well-equipped horse trailer makes a useful triage shelter when it is stocked with pharmaceuticals, diagnostic equipment, chemistry machines, etc. There should be access to fresh water, ice, and quality hay in treatment areas. A generator can provide light for working through the night if electricity is not available. Competent personnel should be available to assist with running fluids and continuous monitoring of sick horses.
Routine paperwork to have available includes consent forms to authorize treatment, medical records, and specialized treatment forms required by AERC or FEI. Should a horse require shipment to a referral hospital, make arrangements in advance so a referring veterinarian and hospital are aware of the case and available to accept it.
Besides a variety of musculoskeletal injuries and lameness issues that occur with athletic pursuits, veterinarians might see metabolic problems. These are typical of endurance exercise and relate to the complex of exhausted horse syndrome: myositis, thumps (synchronous diaphragmatic flutter), heat stress, colic, and the potential of laminitis. Fatigue, energy depletion, electrolyte imbalances, and dehydration must be addressed. Goals are to maintain circulatory health, intestinal motility, and kidney perfusion, to minimize pain and discomfort, and thwart development of laminitis or gastric ulcers. Endurance ride treatment often involves creative thinking and the use of every conceivable resource to make a workable treatment area, often in the middle of the wilderness.