EIC = Exercise Induced
EIC is a common cause
of exercise intolerance and subsequent collapse in what appears to be a
healthy adult Labrador Retriever. Dogs with EIC are normal at rest and
able to tolerate mild to moderate exercise but occasionally become in
coordinated and collapse after 5 to 15 minutes of strenuous exercise.
The syndrome of exercise intolerance and collapse (EIC) is being
observed with increasing frequency in young adult Labrador Retrievers.
Most, but not all, affected dogs have been from field-trial breedings.
Thirty percent of all tested Labrador
Retrievers carry the EIC gene. This is not a problem unless a breeder
unknowingly breeds one carrier to another carrier and ends up with affected
Labrador Retriever puppies. It can take up to 5 years for symptoms to
appear, so it is important that breeders test for this gene. It is also
important for buyers to educate themselves and learn about this debilitating
problem. Ask your breeder if their dogs have been tested and find a breeder
who has done so to prevent problems later on in your dog's life.
For a general overview of EIC, please download
Brochure PDF. For EIC information go to the
EIC Testing web site.
Both Nina and
Goldie tested as non-affected. (It
takes 2 copies of the gene to affect a dog ). Being a carrier is NOT a
problem unless you breed to another carrier. The 2 stud dogs,
Buddy and Charlie
Every dog inherits 2
copies of every gene - one from its dam and one from its sire. EIC is
inherited as an autosomal recessive trait, which means that all
(those showing signs of collapse) have 2 copies of the mutated gene - one
that they got from their dam and one from their sire.
These dogs have no copies of the gene, and do not have EIC, nor
will they show signs of collapse. If bred, they will not pass a copy of the
EIC mutation on to any of their puppies.
Have one copy of the mutated gene that they got from either their
dam or their sire and they have one normal copy of the gene that they got
from the other parent. These dogs do not have EIC and will not show signs of
collapse. They will, however, pass their copy of the mutated gene on to
approximately half of their puppies.
have 2 copies of the mutation, one of which came from each parent.
Dogs with 2 copies of the mutated gene (affected dogs) have EIC and most
will show occasional signs of exercise intolerance or collapse when
participating in trigger activities with a very high level of excitement or
stress. Some affected dogs will never exhibit signs of EIC - this could be
because they do not participate in high excitement strenuous activities or
because they have a laid-back temperament. Affected dogs can tolerate mild
to moderate exercise, but 5 to 20 minutes of strenuous exercise with
excitement induces weakness and then collapse. Severely affected dogs may
collapse whenever they are exercised to this extent - other dogs only
exhibit collapse sporadically and all of the factors important in inducing
an episode have not yet been well established.
A rocking or forced gait is usually the first sign of an oncoming collapse.
Many affected dogs will continue to run while dragging their back legs. it
is as if the back legs can't hold up your dog's weight. You may just think
your Lab is uncoordinated, especially in the hind end. In some dogs the rear
limb collapse progresses to forelimb weakness and occasionally to a total
inability to move. Complete collapse can occur and your dog may even appear
stunned or disoriented. The symptoms can continue to worsen even after
exercise is stopped. A few affected dogs have died during exercise or while
resting immediately after a collapse of exercise-induced collapse so an
affected dog's exercise should ALWAYS be stopped at the first hint of an EIC
Most dogs recover quickly and are usually normal within 5 to 25 minutes with
no residual weakness or stiffness. Dogs are not painful during the collapse
or after recovery. Massage of the muscles or palpation of the joints or
spine is not uncomfortable. Affected dogs are not stiff or sore or limping
upon recovery. Body temperature is normal at rest in dogs with EIC but
almost always dramatically increases at the time of collapse.
exercise-induced collapse (EIC)
A syndrome of exercise intolerance and exercise induced collapse
(EIC) is being observed with increasing frequency in young adult
Labrador retrievers. It has also been observed in Chesapeake Bay
retrievers and curly-coated retrievers. Affected dogs have been
found in field-trial, hunt test, conformation, pet, and service
lines. Black, yellow, and chocolate Labradors of both sexes are
affected, with the distribution of colors and sexes closely
reflecting the typical distribution in the population. Signs first
become apparent in young dogs, usually between 5 months and 3 years
of age (averaging 14 months). In dogs used for field trials, this
usually coincides with the age at which they enter heavy training.
Littermates and other related dogs are commonly affected, but
depending on their temperament and lifestyle, they may or may not
manifest signs. Affected dogs exhibiting signs of collapse are
usually described as being extremely fit, muscular, prime athletic
specimens of their breed with an excitable temperament and lots of
Description of exercise-induced collapse
Affected dogs can tolerate mild to moderate
exercise, but 5 to 20 minutes of strenuous exercise with extreme
excitement induces weakness and then collapse. Severely affected
dogs may collapse whenever they are exercised to this extent; other
dogs only exhibit collapse sporadically. The factors important in
inducing an episode can vary among dogs. The first thing noted is
usually a rocking or forced gait. The rear limbs then become weak
and unable to support weight. Many affected dogs continue to run
while dragging their back legs. Some of the dogs appear to be
incoordinated, especially in the rear limbs, with a wide-based,
long, loose stride rather than the short, stiff strides typically
associated with muscle weakness. In some dogs, the rear limb
collapse progresses to forelimb weakness and occasionally to a total
inability to move. Some dogs appear to have a loss of balance and
may fall over, particularly as they recover from complete collapse.
Most collapsed dogs are totally conscious and alert, still trying to
and retrieve, but affected dogs can appear stunned or disoriented
during the episode. It is common for the signs to worsen for three
to five minutes even after exercise has been terminated. Most dogs
recover quickly and are normal within 5 to 25 minutes with no
residual weakness or stiffness. Dogs are not in pain during the
collapse or after recovery. Affected dogs are not stiff or sore or
limping upon recovery.
Note: A few affected dogs have died during exercise
or while resting immediately after an episode of EIC, so an affected
dog's exercise should always be stopped at the first hint of
Factors contributing to collapse in dogs with EIC
The ambient temperature does not seem to be a critical factor
contributing to collapse, but if the temperature is much warmer or
the humidity is much higher than the dog is accustomed to, collapse
more likely. Affected dogs are less likely to collapse while
swimming than when being exercised on land. There are severely
affected dogs, however, who have exhibited collapse while breaking
waterfowl in frigid temperatures, and some dogs have drowned when
experiencing EIC-related collapse in the water.
Dogs that exhibit signs of EIC are most likely to have intense,
excitable personalities, and it is very apparent that their level of
excitement plays a role in inducing the collapse. There are some
severely affected dogs who require very little exercise to induce
the collapse. Dogs with EIC are most likely to collapse when
engaging in activities that they find very exciting or stressful.
This can include retrieving of live birds,
participation in field trials, training drills with electric collar
pressure, and quartering for upland game.
Type of exercise
Routine exercise like jogging, hiking, swimming, most waterfowl
hunting, and even agility or fly ball training may not induce an
episode in dogs with EIC. Activities with continuous, intense
if accompanied by a high level of excitement or anxiety, most
commonly cause collapse. Activities commonly implicated include
grouse or pheasant hunting, repetitive "happy retrieves," retrieving
drills or repetition of diffi cult marks or blinds where the dog is
being repeatedly corrected or is anticipating electric collar
correction, and running alongside an ATV.
Understanding test results
The inheritance of EIC
EIC is an autosomal recessive syndrome. To be affected, a dog must
have received the mutated version of the EIC gene from both parents.
A dog that has two copies of the normal version of the EIC gene.
Clear dogs will pass on the normal version of the gene to all of
A dog that has one copy of the normal EIC gene and one copy of the
mutated EIC gene. Carrier dogs do not show signs of EIC. On average,
carrier dogs will pass on the mutated copy of the EIC gene to half
of their offspring. By mating a carrier dog to a clear dog, you
will, on average, produce litters that are 50 percent clear and 50
percent carriers, with no affected.
A dog that has two copies of the mutated EIC gene. These dogs are
susceptible to collapse episodes under their “trigger” conditions.
An affected dog will pass on the mutated EIC gene to all of its
offspring. By mating an affected dog to a clear dog, you will
produce a litter that is made up of 100 percent carrier offspring ―
no clears, but also no affected.
Implications of the EIC Mutation for Breeding:
Click here to see the results of Nina's EIC results
Click here to see the results of Godie's EIC
Click here to read about CNM
Click here to got back to "Health Concerns in