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Roger L. Welton, DVM
Roger L. Welton, DVM, Veterinarian
Category: Dog
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Experience:  Licensed Veterinarian, Practice Owner, and Book Author
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Is it safe to breed two dogs that have same father but ...

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Is it safe to breed two dogs that have same father but different mothers?
Hi Demullin3,

What you are talking about is called inbreeding. Experienced breeders sometimes inbreed to fix an exceptional dog's breed traits in the subsequent puppies. However, while fixing desirable traits you also have a higher chance of having undesirable traits and health problems crop up as a result. This is due to having less of a genetic diversity and having a higher chance of getting a recessive gene for an undesirable trait from both the mom and the dad who were closely related.

It is recommended that if you plan on inbreeding that at least 3 generation of the pedigree be examined in great detail for health problems and undesirable breed traits.

I as a breeder, do not recommend breeding closely related as it does introduce a higher chance of health problems and can result in smaller litter size, and weaker immune systems as well. I'd rather have the genetic diversity of 2 unrelated dogs and healthy puppies than potentially having puppies with breed faults or weakened immune system or other health problems.

I know this is probably not the answer you were looking for, but most breeders will agree with this opinion. If you’d like to read more in inbreeding here is a website with additional info.

I hope you find this information helpful.
Customer: replied 10 years ago.
Reply to Jane Lefler's Post: Hello, thanks for your reply. so far this info was just standard stuff you can read in any book. I would like to know what makes you say that it is called inbreeding? I understand the inbreeding part with the father being the same with both dogs, but what I'm puzzled about is that the mothers are different and related in no ways. Can you help clarify?
I absolutely concur with this expert's opinion. From a medical prospective, breeding dogs this close in relation increases the development of double recessive genetic disorders in the offspring. That why the royal families of the 18th century Europe had such high incidences of inheritted disease like mental illness, bleeding disorders, and cancer in the young. They practiced inbreeding to keep royal blood pure. What's more, in most cases, their inbreeding was not even as closely related as sharing one parent the same, but from intermarriage between cousins.

In dogs, inbreeding results in hip dysplasia, cardiac defects, dislocating knees, cancers in the young, fearfulness and agression, etc. The list goes on and on. Inbreeding weakens a breed, contributes to future offspring having to suffer with these diseases, and hurts the people who have to live with the heartache and expense of treating the dogs with these diseases.

Inbreeding is an unethical and irresponsible practice. It hurts both animals and the people who love them. Please do not breed two dogs with the same parent. In fact, cousins should not even be bred together. Genetic variety promotes the health an well being of a breed. Dogs related in any way should never be bred.
Roger L. Welton, DVM, Veterinarian
Category: Dog
Satisfied Customers: 1451
Experience: Licensed Veterinarian, Practice Owner, and Book Author
Roger L. Welton, DVM and 3 other Dog Specialists are ready to help you

On the genetic level, both dogs will have half their genes from the same father. As a result, if there were any genetic dispositions for health problems in the common father, you would have a higher likelyhood of that gene showing up in the puppies of the related mother and father.

This is an example only and I'm using hips for ease in explaination only. It could be a number of conditions. For instance, say the common sire had a recessive gene for bad hips, even though he didn't develop bad hips. Then this recessive gene was passed down to both of his offspring who also do not show signs of bad hips perhaps because both their mothers did not carry a recessive gene for bad hips. When the two dogs are mated, since both carry the gene for bad hips, it is likely that at least a portion of the puppies will develop bad hips as they inherited the gene from both parents instead of just one parent.

In breeding occurs when ever two dogs are bred that are closely related by blood. In this case, half of each dog's DNA comes from the same dog, thus they are half brother and sister.   Of course it would even be more drastic if the dogs were full brother and sister or if one of the dogs was being bred to a mother or father. But regardless, there is a close blood tie between the two dogs and that is considered inbreeding.

I hope this clarifies this for you.