(Excerpt from Spring/Summer 2007 issue of GCNM News)
I am grateful for the help of Suzanne Stack, DVM, in preparing this article. Dr. Stack is a 1985 Ohio State graduate currently practicing near her home in Yuma, Arizona. Previously, she served as a State Racing Board Veterinarian in Wisconsin and as a track vet in Texas at Valley Greyhound Park. Dr. Stack worked closely with Arizona Adopt a Greyhound (AAGI) for a number of years and still volunteers with that group.
The relative lack of information on canine heat-related and exertional ailments is alarming, considering how common the occurrence is among dogs of all breeds, particularly greyhounds. Not surprisingly, there is contradictory information on how to handle these sometimes fatal catastrophes.
Racing greyhounds are finely-tuned athletes and are usually conditioned by professional trainers. A racers performance while training and racing is (or should be) closely monitored. The onset of heatstroke or another debilitating and potentially life-threatening muscle disorder called hyperacute exertional rhabdomyolysis (HER) are two things no trainer wants to see.
Varying degrees of heat/exertional illness require specific treatment approaches to avoid permanent damage to muscle fibers, kidneys, and other organs. An experienced greyhound trainer has the expertise to recognize when a greyhound has been afflicted with one of these medical crises and knows the urgency in administering appropriate treatment.
Once the greyhound has left the racing environment and is lucky enough to be adopted, there are still numerous perils to which the dog may be exposed. One of the most common, yet least considered dangers, is that of over-exertion.
Well-meaning adopters want to give their greyhounds freedom to run and exercise, but it must be understood that unlike humans, dogs do not possess the ability to gauge their fitness and adjust their level of effort accordingly. Retired racers, depending on how long they've been off the track and how compromised their physical health might be, are at serious risk for experiencing critical problems when allowed to over-exert themselves.
Both hyperacute exertional rhabdomyolysis and heatstroke can kill a greyhound, particularly an unfit one. Physical effects can vary, but these two urgent conditions can show similar signs, including heavy panting; generalized muscle pain as evidenced by showing sensitivity to touch; muscle tremors; cardiac arrhythmia; a tendency to drag the hind legs or collapse; and extreme difficulty in changing position from standing to lying or vice versa. Treatment for both these maladies is basically the same, but the key is to administer it quickly.
Immediate, appropriate therapy is vital to the dogs recovery. The body temperature must be brought down as quickly as possible. Rapid cooling can be accomplished with hosing down the dog, applying cool wet towels over the body, and exposure to a fan or air conditioning in house or car. Try to avoid producing a shivering response as this can create more heat in the body.
Transport the dog to a veterinarian as soon as possible and be sure to inform the vets office you are on the way with a dog in severe distress from apparent heatstroke. They can then prepare the necessary items for treatment.
The possibility of resulting bleeding disorders will require appropriate medications and, if available, frozen plasma. Not all vets offices will have plasma, although an emergency vet clinic is more likely to have this on hand.
IV fluids should be administered as soon as possible to prevent the onset of shock and to aid in flushing the kidneys of harmful byproducts leaking from damaged muscles. In researching this article, it is evident there is some disagreement over what solution is best for the IV. Some veterinarians feel .9% sodium chloride (normal saline) is adequate, while others feel it is prudent to use an electrolyte combination solution.
The effects of heatstroke or HER are not corrected in one day at the vets office. In-patient care is necessary for proper treatment and recovery. Several weeks of rest at home may be required for convalescence. Non-steroidal anti-inflammatory medication should help reduce muscle inflammation and subdue the pain. Antibiotics may be recommended by your veterinarian to prevent secondary infection.
Given the greyhounds purpose as a performance dog and the conditions under which they are trained, raced, confined, and transported, it is safe to assume many racers have experienced one or more episodes of heat/exertional ailments. These dogs may then have a predisposition for future episodes of similar illnesses and likely will have compromised kidneys and other organs. Consequently, great care should be taken to protect them from over-exertion and heat-related illness.
The following are some of the risk factors for heatstroke published in The 5-minute Veterinary Consult by Larry Tilley, DVM and Francis W.K. Smith, Jr., DVM: Previous history of heat-related disease; age extremes; heat intolerance due to poor acclimatization; obesity; poor cardiopulmonary conditioning; hyperthyroidism; underlying cardiopulmonary disease; dehydration.
Anecdotal reports from adopters whose greyhounds have experienced heat- or exertion-related episodes suggest that adopters need to be better informed of the dangers of allowing their retired racers free reign to run, particularly in hot, humid conditions. Obese greyhounds will be especially susceptible to the effects of over-exertion. Even on cold days, given the right conditions, a greyhound can collapse from over-exertion.
Extreme excitability in greyhounds, even while on a leash or in a fenced yard, can produce a combination of life-threatening factors which require immediate intervention by at least cooling the dog down and eliminating the stimulus (think high-prey-drive greyhound on a leash as a rabbit runs by!).
People who report coming home to a dead or dying dog should take into consideration the environment when evaluating the cause. Broken air conditioners on hot days, lack of shade outdoors, excessive excitement or exertion (possibly running the fence line with another dog), absence of water to drink, these factors can kill a dog or take them to the brink of death. Hot, humid conditions are by far the most deadly.
The frequency with which adopters report greyhounds dropped dead from a heart attack, when no previous indications of heart problems existed, suggests that death by heatstroke or HER may not be so uncommon. Only necropsy can identify the likely cause of death.
Close supervision of retired racing greyhounds exercise routines, particularly those new to their homes, should be recommended to all adopters. Greyhounds who appear to tire quickly, pant excessively, and/or appear to be reluctant to move after exercise, should be limited to mild or moderate exercise and then, only under supervision.
Close attention to heat and humidity in the environment is paramount in protecting a vulnerable greyhound from heatstroke or HER. A conditioning program similar to that of a human athlete (gradual increase in intensity of workouts) should be implemented before allowing retired racers to engage in physical activities which substantially increase heart rate and respiration.
Greyhounds lucky enough to have been placed in a loving adoptive home deserve to have more than food, shelter, and attention. Responsible guardianship of retired racers includes being armed with the knowledge to protect them from the hidden dangers that await these athletes once they leave the tracks and training farms. A few precautions and observations can save your greyhounds life.