Aussies and Border Collie Collapse

by C.A. Sharp

First published in the Aussie Times July-August 2016

 

Kate first noticed something wrong with her Aussie, Maverick, when he was 3 years old.  It wasn’t much, just a bit of instability – a wobble in his hindquarters after he’d been jumping repeatedly to catch his new Frisbee.  Maverick is a toy-hound.  If it’s a dog toy, he likes it.  But of all his toys, the Frisbee was at one his favorites from the moment he got it and he’d go all-out trying to catch it.   Kate isn’t sure she’d have noticed the wobble at first if she had not been so vigilant about any sign of trouble in the rear leg he’d broken as an adolescent pup.

Maverick and another dog had been enjoying a rambunctious game of chase indoors when he slipped, a hind leg sliding under a decorative trunk.  He sprang up without first pulling his leg free and wound up with a serious fracture. After the initial incident with the Frisbee, Kate assumed the wobble was due to residual weakness in his hindquarters from the broken leg so she put him through a course of muscle-building exercises to improve the strength in his hips and rear legs.   In spite of this the wobbling got worse.

Kate and Maverick had been an active team.  They liked run together, take walks, and play with retrieving toys.  They even tried agility for a while until Kate realized that neither one of them had the focus the sport demands.  Maverick came along on backpacking and climbing trips, wearing his own doggie back-pack loaded with his collapsible bowls, enough food for the weekend, and two or three 8-ounce water bottles. A true Aussie, he loved physical activities with his person.

Troubled by Maverick’s worsening condition, Kate did some research and came across information on Border Collie Collapse (BCC).  She suggested this to her sister-in-law, a vet tech, who arranged for Maverick’s testing to rule-out other possible causes of his episodes and scheduled a follow-up consult with the vet she worked for.  When no other cause for Maverick’s wobbles could be found, Kate enrolled him in the BCC study at the University of Minnesota.

 

Despite the name, BCC is something Aussie owners like Kate as well as Aussie breeders need to be aware of, especially those whose dogs engage in vigorous sports or activities.

BCC is a neurologic disorder in which strenuous exercise may trigger a collapse episode.  People in Aussies sometimes associate the disease with Exercise Induced Collapse (EIC), more properly called dynamin-associated EIC, in the Labrador and other Retrievers.  The researchers investigating this type of EIC became interested in collapsing Border Collies and initiated a study of BCC.  The collapse episodes that occur in Border Collies, Australian Shepherds and several other herding breeds are quite different from those observed in EIC dogs.  BCC is also sometimes called exercise-induced hyperthermia, stress seizures, “the wobbles,” or (mistakenly) EIC.  Occasionally someone will refer to it as malignant hyperthermia, but that condition is actually a very specific, serious, and sometimes fatal genetic disease which is triggered by anesthesia, other medications, and – rarely – exercise.

Most of the time BCC dogs look and behave like normal, healthy dogs.  BCC episodes most frequently occur 5-15 minutes after vigorous exercise but may also begin while the dog is engaged in activity. When this happens the signs tend to worsen during the first five minutes after activity has stopped.  Reactions during exercise can be subtle, as simple as a loss of focus.  Experienced owners learn to notice them so they can stop activity quickly.

Dogs with BCC don’t necessarily have episodes every time they engage in vigorous activity so there must be other factors that trigger the event.   At this point it is unknown exactly what factors those factors are but warm weather or indoor temperature and the dog’s own level of excitement may contribute.  Many affected Border Collies have collapse episodes while herding sheep, engaging in prolonged exercise with a high level of excitement.  Aussies have been reported to have had collapse episodes while doing stockwork or competing in agility.  Once a causative gene is identified, its normal function may indicate what the precise triggers for BCC episodes might be, but at this point only dogs who have a history of strenuous exercise prior to collapse are considered to have probable BCC.

Dogs experiencing a BCC episode often become disoriented, confused or simply lack focus.  They may sway, stagger, scruff their feet, or even fall to the ground.  The gait becomes short and choppy, with exaggerated vertical movement of the legs; if turning, the dog’s legs may cross over each other.  Rectal temperatures may be elevated, averaging 107F (42C, but identical temperatures have been documented in normal dogs after vigorous exercise.  BCC episodes last from 5-30 minutes, after which the dog returns to normal.  While not every exercise session will result in an episode, some Border Collie handlers whose dogs have BCC feel that every episode a dog has makes it more likely the dog will have another.

If you believe your dog is experiencing a BCC episode, stop all activity immediately.  It is rare, but death sometimes occurs during an episode.  Remove the dog to a quiet resting place that is shady or cool.  Use water or a damp cloth to cool the dog down and make drinking water available to reduce any potential for dangerous hyperthermia.  If your dog has BCC it can live a fairly normal life but you will need to avoid activities that trigger the episodes, particularly when the weather is warm.  Since at this point no one knows what actual pathology is causing the collapse there is no specific treatment other than keeping the dog cool and quiet.  Some veterinarians think the episodes may be a type of partial seizure and provide anticonvulsant medication to see if it decreases episode frequency but at this point there is no firm evidence that this is effective.

In a study soon to be published in the Journal of the American Animal Hospital Association, Dr. Susan Taylor of the University of Saskatchewan reports on her studies of Border Collies with BCC.  Examinations and testing of affected and unaffected dogs before and after strenuous ball-chasing or sheep herding exercise found no difference between the the normal and affected groups in blood sugar and calcium, the muscle enzyme creatinine kinase, and electrolyte (sodium and potassium) concentrations before or after exercise.  Initially they also performed muscle biopsies but these were discontinued when all were found to be normal.  The results of thoracic radiographs, echocardiograms, resting ECGs and ECGs after exercise made cardiac-related causes of collapse highly unlikely.

While the specific triggers for BCC episodes may vary from one dog to another, warm or hot environmental temperature, intensity of exercise, excitement during exercise, an excitable disposition, or high stress levels may contribute.  Activity should be limited for affected dogs.  Avoid physically strenuous play, particularly repetitive play such as retrieving balls, discs or other thrown objects.  Normal play activities that the dog initiates itself, like playing with a favorite toy or with another dog, generally do not trigger episodes.

If a BCC dog has been active in physically demanding activities that repeatedly induce collapse episodes, including stockwork or competitive physical events like agility or fly-ball, it should be retired.  While there do not appear to be long-term health risks even after repeated episodes, there have been some reports of dogs dying during an episode though at this point it is unknown why the condition might prove fatal.  In demanding or critical real-life work environments, including stockwork, service for the disabled, search-and-rescue, or other tasks demanding top physical and mental performance, an episode could put the dog or even its handler at risk.

BCC is probably inherited.  It has a strong breed predisposition, occurring in Border Collies around the world as well as in closely related breeds like Aussies, Kelpies, and Shetland Sheepdogs.  The study currently underway at the University of Minnesota has enrolled several affected sibling and parent/offspring pairs as well as more extended family groups.  There is not currently any specific information on how BCC is passed or what gene(s) might be involved.  Dogs with BCC do not have the dynamin 1 (DMN1) mutation that causes EIC in Labrador Retrievers and other breeds for which there is a DNA test.  Those who suspect their Aussie might have BCC should not use that test as a way to diagnose their dogs or clear related breeding stock.  Dogs with BCC should probably be withdrawn from breeding and certainly should not be bred tight on their own pedigrees or to mates with a family history of BCC.

Dr. Jim Mickelson and his team at the University of Minnesota are studying BCC in collaboration with Dr. Taylor, whose study evaluating BCC affected dogs before and after exercise is mentioned above, and Dr. Diane Shelton at the University of California-San Diego. The Minnesota group is collecting and reviewing owner-provided questionnaires and videos of collapse episodes, along with DNA samples from affected dogs for genetic analysis.  Identifying the underlying genetic factors could lead to better diagnosis and treatment for the disease as well as possibly providing a DNA test that would help breeders select away from BCC.

If you have a dog which has Border Collie Collapse, or which you think might have it, please participate in the study.  You will be asked to complete a questionnaire and submit a blood sample from your dog.  If possible, they would also like a video of the dog having an episode so they can determine whether it is typical of BCC.  They can also use DNA samples from working or performance event dogs that are over eight years of age and both episode and seizure free; these dogs can be helpful as “controls” for both their BCC and epilepsy studies.

 

Kate and Maverick have learned to live with his BCC.  When they engage in play he finds exciting, she sets a timer for 5½  minutes so they quit before he starts to have an episode.   In summer, when the weather is hot and humid, she sets it for 4 minutes, keeps ice cubes available as drinking water, and gives him a spray down at the end of the session.  Maverick still enjoys the backpacking and climbing trips without incident so long as he doesn’t get over-excited and run around too much.

          The author would like to thank Katie Minor of the University of Minnesota and Susan Taylor, DVM, ACVIM,of the University of Saskatchewan for reviewing and fact-checking this article.  She would also like to thank Kate Jester for sharing Maverick’s story.