Part of the official UK Kennel Club testing scheme in Collie (Smooth), Retriever (Labrador), Retriever (Chesapeake Bay), Retriever (Curly Coated) and Spaniel (Clumber)
Exercise Induced Collapse (EIC) is an inherited condition that primarily affects Labrador Retrievers and their related breeds – mainly Labrador crosses. The variant responsible has also been found in other breeds, including Curly-coated Retrievers, Boykin spaniels and Pembroke Welsh Corgis. The signs of EIC typically become noticeable when dogs undergo rigorous training. The initial symptoms usually manifest between the ages of 5 months and 3 years, although there have been cases where affected dogs didn’t experience collapse episodes until as late as age 10. Dogs with this condition can tolerate mild to moderate exercise, but after engaging in heavy exercise for a duration of 5 to 20 minutes, they experience weakness and collapse. While some dogs may only exhibit collapse episodes sporadically, severely affected dogs can collapse whenever they are exercised to this extent. The condition can be exacerbated by excitement and high temperatures.
During an episode, the first symptom observed is often an abnormal gait characterized by rocking or forced movements. The hind limbs then weaken, making it difficult for the dog to support its weight. Many affected dogs continue to run but drag their back legs. Some dogs display a lack of coordination, particularly in the hind limbs, with a wide-based, long, and loose stride instead of the typical stiff strides associated with muscle weakness. In certain cases, the collapse progresses to weakness in the front limbs and occasionally leads to complete immobility. Some dogs also exhibit a loss of balance and may fall over, especially during the recovery phase. Although most collapsed dogs remain conscious and alert, actively attempting to run and retrieve, around 25% of affected dogs may appear stunned or disoriented during the episode. All affected animals should be withdrawn from work and should avoid situations involving excitement and/or stress.