Born With Missing Teeth

Congenital Defect among Australian Shepherds

Australian Shepherds

Australian Shepherds were recognized by the AKC in 1991. They are described as a working dog. They work mainly in herding, using their teeth to nip the ankles of animals they herd. Teeth and proper use of their snouts are required in herding. Missing teeth in Australian Shepherds comes from being born with the absence of teeth, not the loss of them.
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History

  • Congenital Palatal Defect
  • Increasing problem after 1980s
  • Shorter muzzles became more popular
  • AKC agreed - changing description to state “muzzle is equal to or slightly shorter than the back skull.”
  • Past few generations selection for shorter muzzles have increased frequency of missing teeth

What do we know?

  • There is not a lot known about the specifics of inheritance.
  • Due to complexity of the jaw and the fact that the mode of inheritance is different among breeds, missing teeth is a polygenic trait.
  • Because missing teeth is a polygenic trait, its harder to determine what is being inherited. To decrease the frequency, Australian Shepherds with missing teeth are not bred with others that also have missing teeth. If the amount of missing teeth and presence of other dental defects, the dog is not used for breeding purposes.

My opinion

Although missing teeth is a polygenic with many factors, I think one of the main issues is due to inbreeding. Because certain traits are deemed to be what a breed should look like, breeders will select individuals with the capability of producing those traits. This leads to a small variability among traits, causing inbreeding. This increases the chances of birth defects and medical issues. There needs to be a less strict description of what the different breeds can look like in order to decrease chances of issues being passed down in generations.

References

"Australian Shepherd." American Kennel Club. Web. <http://www.akc.org/dog-breeds/australian-shepherd/>.


"Missing Teeth." Australian Shepherd Health Genetics Institute. 1 Mar. 2013. Web. <http://www.ashgi.org/home-page/genetics-info/teeth-and-jaws/missing-teeth>.


Sharp, C.A. "A Close Look at Canine Dentition." Aussie Times. Australian Shepherd Club of America, Inc., 1 July 2002. Web. <http://www.ashgi.org/home-page/genetics-info/teeth-and-jaws/so-bite-me-a-close-look-at-canine-dentition>.


Sharp, C.A. "The Backyard Geneticist." The Institute of Canine Biology. Australian Shepherd Health & Genetics Institute, Inc., 1 Jan. 2014. Web. <http://www.instituteofcaninebiology.org/uploads/1/9/6/9/19691109/ca_sharp_-_backyard_geneticist.pdf>.