Inbreeding in Dogs

Our question this week was:

What happens when brother and sister accidentally mate? Does anything bad happen to the puppies? Do they come out ok or are they more likely to come out with abnormalities?

Christopher Aparicio


Hi – thanks for your email. Inbreeding is breeding between close relatives, such as brother and sister. Your question is what happens when they mate and will the puppies be okay or have abnormalities?

Inbreed animals often have reduced more health problems and physical defects. Genetic problems are more common; there is increased infant mortality, slower growth rate, smaller adult size, loss of immune function and other possible problems.

It is possible that the litter could be okay but also possible there could be multiple problems. It is a very bad idea to purposely breed littermates.

Dr. Debra

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