There are many misconceptions about dogs and having a litter. For instance some people believe that female dogs can get pregnant any time they are together with a male dog. (Not true.) Or they think that female dogs come in season three or four times per year. (Not true, unless the dog has some kind of health problem.) Every dog is different, but most female dogs come in season every six to nine months. Some dogs only come in season every 12 or 14 months. Another popular misconception is that dogs often have litters with 15 or 20 puppies in them or that they will have a dozen puppies every time they have puppies. Again, no. If you're wondering, “How many puppies will my dog have?” it will depend on a number of factors.
When it comes to puppies and litter size, there is a big difference (no pun intended) between large breeds and small breeds. In general, bigger dogs have litters with more puppies in them, and smaller dogs have fewer puppies in their litters. This is partly due to space considerations. Bigger dogs simply have more room in the uterus to support larger litters. While the birth size of puppies is partly dependent on the breed (Mastiff newborns are bigger than Pekingese newborns), puppies at birth do not vary as much in size as adult dogs do. At birth, puppies will range from a few ounces to over a pound, regardless of the breed. It would obviously be difficult for a Toy dog to carry puppies that weighed a pound when many Toy dogs weigh less than 10 pounds, so their puppies typically weigh just a few ounces at birth. On the other hand, larger dogs, weighing 60-70 pounds or more, can easily have newborn puppies that weigh over a pound. A Toy puppy may only be able to carry two or three, or perhaps only one puppy in a litter, while a larger breed of dog may easily whelp eight to 10 puppies.
According to the American Kennel Club, the average litter size for all breeds and varieties that they register, which includes the tiniest Chihuahua and the largest Great Dane, is 7 puppies per litter.
According to a three-year study conducted by the AKC, which included 15 breeds and 728,271 litters to gather data on litter size, ages of dams, and number of litters, they found the following information about popular breeds.
Average Puppies Born to Popular Breeds
- Labrador Retrievers had a typical range of 5 to 10 puppies per litter, with an average of 7.6, based on over 85,000 litters
- German Shepherd Dogs had just over 44,500 litters with a range of four to nine pups and averaging 6.6 per litter
- American Cocker Spaniels had 39,000 litters and an average litter size of five, with a normal range of three to seven pups
- Shetland Sheepdogs produced over 28,400 litters, revealing a typical range from two to six pups, averaging 4.3 per litter
- Yorkshire Terriers were represented in just over 53,000 litters, showing a range of two to five pups and averaging 3.3
- Chihuahuas produced just over 55,000 litters, showing a range of two to five pups and averaging 3.3
Female dogs having their first litter, and older females, tended to produce smaller litters. The care the female dog receives before breeding and during pregnancy also play a great role in determining how many puppies she will have. It is not unusual for a number of eggs to be fertilized and to have some of them not implant in the uterine wall or, if they are implanted, to later be "resorbed" before whelping. Breeders who have their dogs ultrasounded between days 28 and 35 can see how many embryos have been implanted, but sometimes fewer puppies are ultimately born. In some cases an entire litter is resorbed.
In some cases inbreeding will also reduce the size of litters. Purebred dogs exist in a closed system. That means that no new genes are being introduced from outside the existing dogs in the breed. The genes that exist in the breed are simply being re-shuffled when dogs are bred. If breeders are not careful then dogs can be too closely bred to each other and it can begin to affect litter size and the vitality of the breed. Most breeders are aware of this situation and keep track of information such as coefficient of inbreeding (COI) which measures how closely related dogs are to each other when selecting dogs to breed.
It's difficult to estimate what size litter you will get if you have a mixed breed dog. It will depend on the dogs in your dog's ancestry, for one thing. If your dog is part Labrador and part German Shepherd, and mates with another dog that tends to have larger litters, you can probably expect to have a lot of puppies. On the other hand, if you have a Chihuahua mixed with another Toy dog, you will probably have a smaller litter.
There is such a thing as “hybrid vigor” and it should benefit a mixed breed litter to a certain extent, but your female dog will also be affected by her size. Remember that there is only room in her uterus for so many puppies. If she is a tiny dog she can only carry a limited number of puppies, especially if they are very large. If she mates with a very large male, the puppies may be large and she might only have a couple of puppies. If you have a very small female and the father is very big, you should watch her carefully when she goes into labor in case she needs assistance. She might need to go to the vet for a C-section to remove the large puppies.
If you have a large female and the father is small, you could have a lot of puppies. She is capable of carrying all of the eggs which were fertilized and there is no limit on how much sperm a small healthy male dog can produce. The good news is that she should be able to whelp them easily.
Very small dogs can also have a harder time with whelping litters than medium and large dogs. Medium and large dogs with long, flexible bodies tend to have a relatively easy time getting in position and whelping, while many Toy dogs have a much harder time. In some cases small dogs need to plan to have a caesarian section for a normal delivery.
No matter how good the care, not all puppies survive. Canine herpes virus, chills, or other unforeseen difficulties can kill a newborn puppy very quickly. Even if you have a large litter, not all puppies make it through the first week, or live to go to their new homes. It's heartbreaking when a young puppy dies but there's often nothing you can do, even with veterinary help.
Hopefully this information will help you get some idea about how many puppies you might have if your dog becomes pregnant. Breeding your dog is a big undertaking but having a litter of puppies is a wonderful experience, provided you are ready for it.