Thank you for researching this really important question in such a delightful breed!

It is very common for a dog to begin lactating as early as one week before labor begins. Milk can also be a sign of False Pregnancy, since the hormones in a non-pregnant dog after a heat cycle are just about the same as during pregnancy. It is best to confirm pregnancy and the number of pups to expect by having your veterinarian take an xray during week 8 (when the pups' bones will be visible).

Milk production is partly a matter of timing, from our point of view, and partly a matter of stimulation of the hormone system by the labor and suckling of the puppies! Oxytocin, which is the primary hormone of labor and delivery, is also the primary hormone that starts lactation.

Since there is so much variation from gal-to-gal, we just can't rely on this as a sign of impending labor.

The most reliable way to tell when the litter is due (beside counting 9 weeks from the mating dates) is to begin taking Momma's temperature (rectally) three times daily.

***24 hours before labor begins, the temperature will drop from her normal (usually 100-99.5F degrees in a really pregnant mom) down toward around 98F degrees.***

Taking the temperature at points throughout the day will help you "catch" the temperature drop and time the onset of hard labor (again, within 24-30 hours of the temperature drop).

***Please be sure to have your local veterinary emergency service phone numbers at hand in case you need assistance during delivery...most litters are born overnight. Bulldogs are known for needing c-sections due to a variety of birthing problems...most "show" breeders blood test for ovulation dates and schedule c-sections with their vet offices.***

Here is a link to a very affordable and veterinary-school-quality book about dog breeding and puppy care. This is something that many breeders like to have on hand:

http://www.us.elsevierhealth.com/product.jsp?isbn=9781416031390

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