There are a lot of old wives tales surrounding when a dog can or cannot get pregnant. Some people believe a dam cannot get pregnant during her first heat cycle. Others believe a pair of dogs must mate multiple times before pregnancy can occur. But the reality is that neither of these things is true. A female dog can be impregnated when mating with a male as long as they are both sexually fertile, which will usually happen by the time they are one year old.
When dogs can become pregnant
Dogs can successfully reproduce any time after they hit puberty. Dog breeds may vary in when they reach sexual maturity, though most will be able to breed by one year old. For example, according to Sarah's dogs, the German shepherd breeding age for male and female dogs is five-to-six months, whereas a Doberman pinscher may not reach sexual maturity until 18 months of age.
Female dogs become less fertile after they are middle-aged, or around five years old according to Breeding Business. Dogs do not go through menopause and will continue their heat cycle throughout their lifetime, but it will become less frequent and the likelihood of her getting pregnant decreases sharply.
More importantly, the risks to the mother and puppies during a late-life pregnancy increase as the dog ages. Male dogs also become less fertile as they age, but they stay fertile for longer than females and can continue to impregnate females until very late in life.
The dog heat cycle
Dogs only go through their heat cycle once every six months or so, first having a period and then ovulating shortly afterward. The dog heat cycle lasts between two and four weeks according to the American Kennel Club.
A female will be most fertile when the bleeding stops and the discharge turns clear, which is usually about 10 days into the cycle. If you are trying to maximize the chances of your dog getting pregnant on the first time she breeds with a male, this is the right time to introduce the two. This peak fertility will last five days, but the dog can become pregnant all the way until the end of her cycle.
It is worth noting that male dogs do not have a heat cycle and can breed any time, all year round.
When to breed a dam
While dogs can get pregnant as early as their first heat cycle, most professionals advise waiting until at least the third cycle to breed a female. That means she should be at least 18 months of age and possibly older. That is because she has not yet reached full physical or psychological maturity during her first two cycles. Breeding too young can put too much pressure on a young mother's still growing body, and she will also be more likely to reject the puppies or act aggressively towards them according to Breeding Business.
Signs of pregnancy in dogs
If your female dog mated with a male, you'd want to keep an eye on her to see if she has become pregnant. Noah's Ark Vet says signs of pregnancy in dogs include lethargy, changes in appetite (she'll likely eat less at the beginning of pregnancy and more later on), wanting more or less affection than usual, enlarged or discolored nipples, weight gain, an enlarged abdomen and nesting behaviors. If she demonstrates any of these signs, take her to a vet to find out if she is pregnant. If she is, you'll need to know the proper way to care for her during the pregnancy and how to help her during the labor, delivery and first few weeks of the puppy's lives.