Congenital Tooth Defect

Australian Shepherds Born With Missing Teeth

History

  • This disorder is Polygenic, meaning there are multiple genes contributing towards its expression
  • It can result in a small or large number of teeth missing
  • This disorder is so well known that Australian Shepherds in show may not get marked down for missing teeth, so long as the appearance is not severe (however, full dentition is obviously preferred)
  • Has been a known genetic disorder for over 25 years

Diagnosis

It is important to differentiate broken teeth from missing teeth. Some animals break off their teeth during play or on bones. Broken teeth are harshly judged in the show world, and they have criteria that helps them evaluate broken teeth from missing teeth in the show ring. It is important to differentiate between broken teeth and missing teeth, as animals who have broken their teeth should be treated by veterinarians in case of abscesses or fragments of tooth left under the gums.



Canine Dentition

What Do We Know About This Disorder?

Unfortunately, This disorder is not widely studied. The genetic mode of inheritance has not yet been established, and it is unlikely that this disorder will obtain priority in studies because it is generally not a harmful disorder. Missing one or two teeth will not hurt the animal, however unsightly it may be. If this disorder had lethal or harmful effects it would receive much more attention. The phenotypic expression of this disorder is one or more missing teeth at birth, however the genotype or how the gene is passed on to offspring is still unknown.

Why Is This Disorder Harmful?

For the majority of companion animals that are born with missing teeth, this defect does not make much of a difference on their quality of life. If this were to be present in wild canids, there could be many disadvantages to not having full dentition such as less effective hunting or tearing of flesh. The majority of Australian shepherds are kept as pets who can have a diet adjusted to their needs. That being said, the lack of a large number of teeth could cause the canine difficulty eating or jaw problems.


The prevalent disadvantage to Shepherds with missing teeth revolves around the show ring. Although judges are not supposed to mark down for a tooth missing here or there, there is a definite bias towards full dentition.

What is Being Done to Control this Genetic Disorder?

Currently there is no genetic testing to determine if dogs that present phenotypically normal (full dentition) could pass on the gene to their offspring. However, breeders are urged to retain from breeding dogs that are missing teeth in an attempt to reduce the prevalence within the breed.

Opinion

Although I can see how severe cases of missing teeth could effect the life of Australian shepherds, I believe that there are many other disorders that are more important to screen for. Breeders that have studs or bitches that are known carriers or exhibitors of this disorder would absolutely be acting irresponsibly to continue to breed these dogs. I do not believe that we need to go much further to try and eradicate this disorder than discontinuation of breeding affected individuals because of the non-lethal, generally non-harmful nature of this disorder.


Breeders with puppies exhibiting this disorder should educate clients on the status of their puppy's teeth, and what ramifications this may have on them in the future. They should be responsible for explaining to buyers the fact that this disorder will most likely not impede on their home life, but may harm their scores in shows.

Prompt for Discussion

Should diseases that are most harmful aesthetically (missing teeth) receive much attention from research professionals? Or should they be essentially disregarded to focus on more devastating diseases?



After considering it from an ethical perspective, consider it from the viewpoint of a Australian Shepherd show breeder. Could the creation of a genetic test for this disorder significantly increase their success producing champions? Who should be responsible for paying for research in this area?

References

L. Tracy, (2007) The Australian Shepherd. TFH Publications Inc.


M. Rouge, (2003) Dental Anatomy of Dogs. Colorado State University. Accessed April 30, 2013. http://www.vivo.colostate.edu/hbooks/pathphys/digestion/pregastric/dogpage.html


Australian Shepherd Health and Genetics Institute (2013) Australian Shepherd health & Genetics Institute Inc. Accessed April 30, 2013. http://www.ashgi.org/index.htm