Hypothermia

Posted on December 6, 2004 by Martin Coffman, DVM 

After 30 years in private veterinary practice, I can recall many cases of hypothermia in my canine patients. Even in the Deep South, this condition was not rare. In fact, it may be more common in normally warm climates because owners are less aware of the danger and may not take precautions as an owner in the far north would.

The vast majority of dogs presented with hypothermia in my practice came from their kennels and not from the field or duck blind. In areas where ice is common, dogs that fall into ice water are certainly susceptible to hypothermia but, again, most of the cases I saw were affected in their kennel.

Symptoms
Hypothermia can be classified into three categories: Mild with rectal temperatures of 90-99° F (32-35° C); Moderate with temperatures of 82-90° F (28-32°C), and Severe with temperatures of less than 82°F (28° C). A rectal thermometer should be in each owner's doggy first aid kit.

The actual signs a dog exhibits as a result of hypothermia reflects the severity of the condition. Mild cases will show mental depression, weakness, shivering, and lethargy. Dogs that shiver in a hunting situation but are mentally alert and active are not normally hypothermic. Shivering is a normal mechanism that dogs use to generate body heat. Moderate hypothermia can result in muscle stiffness, slow heart rate, slow breathing, and stupor. Severe cases often show fixed and dilated pupils and coma with very difficult breathing.

Most healthy, acclimated hunting dogs can withstand very cold temperatures but dogs with low thyroid function and older dogs are predisposed to hypothermia. These dogs need special care during cold weather hunting.

Prevention
The key to preventing hypothermia is to lessen dangerous exposure to the cold. This includes icy situations afield or in the blind but really goes more to the overall health of the dog. A through physical examination by your veterinarian at least eight weeks before hunting season begins is a crucial first step. The doctor can look for signs of thyroid dysfunction and assess the overall health of older dogs.

Nutrition can play a role. Hard hunting dogs should be fed a diet with a minimum of 430 kcals/cup of food beginning eight weeks before hunting season and throughout the entire season. The caloric content of a food should be available from the manufacturer's Customer Service department.

This type of diet provides the extra calories necessary for optimal performance and nutritionally supports good body condition to help ward off hypothermic situations. Almost all of the dogs presented to me in practice with serious hypothermia were thin and had a sparse hair coat.

Neoprene vests are controversial in that some feel that they keep the dog wetter than allowing it to dry off after a wet retrieve. I use one on my own dog because when I feel under the vest, it feels warm. To my knowledge, there is no research that documents the value of these vests but common sense tells me they help.

Kennel facilities should be evaluated. Again, the vast majority of dogs presented to my clinic with low temperatures came in from a marginal kennel environment. Draft free housing with supplemental heat is optimal. Bedding helps some but there is no substitute for indoor housing in bad weather. Sled dog trainers in Alaska use serious bedding that is changed very often. Their dogs are acclimated to serious cold weather and can withstand very cold temperatures better than the typical hunting breeds we see in the lower 48 states. I like safe, supplemental heat in a kennel or moving the dog indoors if they are in the high-risk categories, e.g. older dogs or dogs with other health problems.

Treatment
First aid for hypothermia in the field should focus on the slow warming of the dog. Attempts at rapid re-warming by non-professionals may have a deleterious effect on the dog. Use warm clothing or blankets to begin the warming process. Supplemental heat, e.g. a truck heater in the cab is fine but a layer of protective material should surround the dog. Do not put the heater near the legs as this may cause dilation of the vessels in the legs and actually make warming of the dog's body core to be delayed. Rush the dog to a veterinary clinic. The doctors may use special techniques like warmed IV fluids, a warm water enema, and warmed air to help the situation.

Hypothermia is a serious situation. Aggressive veterinary care is often needed. Prevention is the key. Warm draft-free kennels are basic. Special care for older dogs and dogs with other health problems is important. Optimal nutrition can play a role. And, common sense is hard to beat.