Study looks at ways to prevent heat-related illness in dogs

By Sarah Carey

Mike Rivers, dog handler, performs a "bite and protection" exercise with Xander, one of the animals that participated in the recent UF study of heat stress in dogs. (Photo by Robbie Kuyrkendall)

Working dogs, such as K-9 officers, war dogs serving during military conflict, or rescue dogs who help with search and rescue efforts after natural disasters, often find themselves in life-threatening situations. But something seemingly more benign is often responsible for taking the lives of these animals — heat-related illness.

In working dogs, overheating can lead to dehydration, exhaustion, impaired ability to work or even death. But there are no evidence-based guidelines for preventing such heat-related issues.

Now University of Florida researchers have conducted preliminary studies that may help fill that void and guide the prevention of heat-related illness in working dogs. They recommend that, as much as possible, dogs work for short periods in morning and evening hours when the temperature is lower, and are kept in shady, well-ventilated areas.

They also recommend that dogs wear protective Kevlar vests in dangerous situations, because despite concerns, there wasn’t evidence that the vests contribute to overheating. In addition, specially designed cooling vests can be used to help dogs cool down faster after strenuous work.

The findings were presented Jan. 14 at the 28th International Canine Sports Medicine Symposium in Orlando.

“We don’t know what a ‘work-rest’ schedule should be under different environmental conditions,” said lead researcher, Dr. Sheilah Robertson,  formerly a professor of veterinary anesthesiology at the UF College of Veterinary Medicine, now an assistant director of animal welfare at the American Veterinary Medical Association. “These are real concerns, especially in the South in the summer as well as for working dogs deployed to the Middle East.”

Although most seasoned handlers try to minimize the risks to their dogs in hot and humid conditions, recommendations are based on best guesses or those used for humans. But big differences in physiology mean there is a limit to the usefulness of such efforts. For example, whereas humans use sweating to cool the body, dogs rely more on panting.

Working K-9s have often made headlines over the past decade because of high-profile assignments such as deployment in the aftermath of the 9/11 attacks, their use in rescue efforts after Hurricane Katrina, and even in hunting down terrorist mastermind Osama Bin Laden last year in Pakistan.

Acquiring and maintaining working animals is expensive. Each fully trained dog represents at least a $30,000 investment and countless hours of training. The true value of working dogs, however, can’t be measured in dollars, Robertson said.

“What would also help us, as trainers, would be guidelines and explanations of the symptoms that we should be on guard for, so that we can recognize heat stress before it is serious,” said Phil Hoelcher, an internationally acclaimed Shutzhund trainer who has worked with many police departments and K-9 handlers around the U.S.

“We have experiences in that field that once a dog’s temperature starts to spike, it is very hard to reverse it without going to our emergency methods of cold water, ice, fans, etc. We know that if it possible for even the most experienced trainer to miss the signs, it is not surprising that pet owners and less experienced trainers don’t even realize it is happening until it is too late.”

In the UF study, seven dogs went through intense 10-minute sessions that involved running at high speed, locating a hidden person and apprehending a “suspect” by grabbing hold of their arm. Dogs performed the exercise with no vest, with a protective Kevlar vest and with a cooling vest that uses patented rechargeable packs to help maintain a comfortable body temperature.

The dogs’ blood glucose, acidity levels and other values were measured, along with pulse and respiratory rates and rectal and core body temperatures before, and immediately after activity and throughout recovery periods. The study, funded through a $19,000 Morris Animal Foundation grant, was carried out during summer and winter months.

Robertson and co-investigator Dr. Kirsten Cooke,  an associate professor of small animal medicine at the UF veterinary college, found that it took dogs longer to return to baseline temperature in the summer than in the winter; in many cases 50 – 60 minutes longer.

And rectal temperatures were higher than those at the body’s core. In the summer the rectal temperatures could be 2.5 degrees Celsius higher than the core temperature, the researchers said. Dogs often needed more than an hour to cool down after intense summer exercise, and cooling vests helped some of them cool down faster.

“Our statistician also found no evidence that the Kevlar vests caused any difference in temperatures compared to dogs wearing no vest, both in summer and in winter,” Robertson said.

“We recommend seeking more data on the use of cooling vests, and correlating rectal and core body temperatures to have a better understanding of how hot the dogs really are,” she added. “In addition, we would like to see more studies of different cooling methods, such as fans, air conditioned recovery areas or standing in water, and more research into the effect of repeated work cycles on the dogs over time.”



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