My name is ***** ***** I’ve been involved professionally with dogs in the health and behavioral fields for over 18 years. It will be my pleasure to work with you today.
While mating too dogs with a close relationship like half siblings can result in some issues for the pups, the pups might aslso be perfectly normal with no behavioral or physical issues. You will have a higher chance of deformities or behavioral issues if any of the mother's ancestors are also closely related to one another. You will need to be prepared in case there are issues with the pups, but they will likely be fine. I would notify any potential new owners of the pups that they do share a common grandmother just so they know that.
Now vets have a mismate shot but the side effects in my opinion are worse than allowing the female to have the pups. Often a female will end up with a uterine infection as a result of the injection and end up needing spaying. You can have her spayed right after her heat cycle before any pups are well developed and avoid the litter that way. In some cases, vaccination will lead to a dog reabsorbing pups as well but you can not count on that to prevent this pregnancy from going full term.
At this point, you have just a few options. If you plan on breeding her in the future, you could have the mismate shot given but have the chance of her needing an emergency spay if she develops a uterine infection (pyometra) which isn't caught early enough or doesn't respond to antibiotics if caught early. The second option is going ahead and spaying her right after she is finished the heat cycle. This effectively gets rid of the pups early in the pregnancy and prevents future pregnancies. The other option is letting her continue with the pregnancy and having the pups.
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