Exercise Induced Weakness and Collapse in Labrador Retrievers

Labrador retrievers are one of the more active dog breeds. Part of having a Lab in your family is to become accustomed to having a high energy dog that plays and exercises a lot. Most dogs will slow down or stop when they are tired and will have no problems, but some revel so much in activity that they will exercise until they become weak and collapse from exhaustion. This is called exercise induced collapse in Labrador retrievers. Problems usually occur during periods of intense activity or excitement. At other times, these dogs seem completely normal.

Symptoms are first seen in young dogs between five months of age and three years of age. The disease does not seem to affect one gender more than the other. Labs bred to be field trial dogs may be more likely to have the problem, and Labs that are easily excited are more likely to have the problem. Collapse is most likely to occur when the temperature and humidity are high, and during activities like upland bird hunting, repetitive retrieving, long, hard running, and intense play, but any very intense activity can lead to collapse.

Symptoms and Types

• Signs begin after five to twenty minutes of extreme exercise, excitement, or stress
• Not walking or running normally (rocking gait)
• Weak back legs
• Dragging the back legs while running
• Standing with the feet too far apart (wide-based stance)
• Picking the feet up too far while walking or running (hypermetria)
• Falling over while running
• Unable to move the head and all four legs after exercise
• Stiff front legs while collapsed
• Most dogs are alert
• No pain while collapsed
• High body temperature
• Occasionally, confusion
• Rarely, seizures and death
• No symptoms between times of collapse
• Recovery usually within five to twenty five minutes

Causes

• An inherited problem in Labrador retrievers
• More than one puppy is likely to be affected in a litter that has the problem

Diagnosis

You will need to give a thorough history of your pet's health, including a background history of symptoms, and possible incidents that might have led to this condition. During the physical examination, your veterinarian will pay close attention to the nervous system, musculoskeletal (muscles and bones) system, and cardiac system. Dogs with exercise induced collapse will typically have a normal physical examination. Your veterinarian will also order a complete blood count and biochemical profile. These will confirm that your dog's internal organs are working properly. Your dog's thyroid hormone level may also be checked to make sure it is normal. Other blood tests can be analyzed to see if other muscle diseases might be causing your dog to collapse. To make sure that your dog is not suffering from a heart problem that comes and goes, your veterinarian may want your dog to wear a special monitor for a day or two to track normal heart rhythm. Or the doctor may want to watch your dog exercise and then do the blood tests after your dog starts to show symptoms. The results of these blood tests will be compared to the blood tests that were done before your dog was exercising.