There are a number of behavioral signs that a dog is ready to give birth, including a loss of appetite and restlessness. A pregnant dog will lose interest in food about 24 hours before delivering her puppies, according to PetMD.
The gestational period for a dog is roughly 58-65 days, or 9 weeks. The actual due date can be estimated using and abdominal radiograph and close observation of the mother from day 56.
A female dogs temperature should average 101.5 Fahrenheit; this will drop by approximately 2 degrees 24 hours before labor begins. Taking her temperature twice a day will give the owner an idea of her average temp and the potential day of arrival.
Milk production will also begin about 24 hours before labor in new mothers; in previous mothers, milk production can begin as late as 4 hours before labor. The dog will then become restless, frequently shifting positions; she will refuse food and may vomit due to nervousness. Hours before labor begins, she will expel a mucus discharge and begin to experience contractions.
When the dog begins to strain and shift into an urination position, this signals the start of labor. A greenish fluid-filled sac will be expelled before or along with each puppy, although in larger-than-normal litters, some sacs maybe retained for a day or so. If there is any sign of abnormality such as straining for long periods without the presentation of a puppy, call the veterinarian for assistance.