So here is one article about the whole heat cycle and also mentions toward the end of the article the reason why not to spay until well after heat cycle. Here they say 70 days, but that would just be 10 days after (false) whelping date and just entering the lactating/puppy fixation time. I've never been able to find the original place that I read to wait 4+ months, as that gets the hormones completely settled into "weaned and gone/zero puppies on my mind" stage. ***Edit to say they said "well AFTER the 70 day diestrus period" so that does match my thoughts.***
veterinarypartner.vin.com
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False Pregnancy in Dogs
We get a lot of questions about female dogs having their menstrual periods. In fact, the menstrual cycle is a primate phenomenon; dogs have an estrus cycle that includes a period of false pregnancy. This false pregnancy can last for weeks with the dog producing milk and sometimes mothering a...
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