While 101 dalmatians may be quite a stretch, the size of some dog’s litters can be upwards of 18 puppies. It also is possible for a dog to give birth to just one puppy, called a singleton. There are several factors that contribute to the size of a litter of puppies, not the least of which is the size of the breed of dog.
In general, smaller dog breeds have smaller litters because their body size does not allow them to carry large litters. On the other hand, while larger dog breeds are capable of carrying larger litters, and often do, size alone does not guarantee a large litter. In fact, there is more variation in the potential litter size of large dog breeds than small dog breeds.
The Female Dog’s Physical Fitness and Nutrition
Healthy and trim female dogs are more likely to have larger litters than those that are overweight. Additionally, nutritionist Russ Kelly found that adding extra protein supplements to a female dog’s diet during pregnancy actually decreases the odds that she will have a large litter. It is best to feed a pregnant dog only a quality commercial dog food with no supplements.
The Dogs’ Ages
As the male dog ages, the quality and count of his sperm decreases. Larger litters are more likely when the male dog is under the age of five years with the potential to produce quality sperm in greater quantities. These sperm are better able to reach and penetrate the female’s eggs. The female dog’s age also can influence her litter size. When a female dog is not bred until the age of four years, chances are that her litter size will be smaller than if she had been bred early on. The AKC recommends that females begin breeding during their second heat. The first heat in a female usually occurs between six and 18 months.
Pregnancy History and Method of Fertilization
The first four to five litters of a female dog generally are larger than litters produced after the fifth breeding. Females also commonly produce increasingly larger litters with each pregnancy through their first four years of life. Another consideration for litter size is the method of fertilization. With artificial insemination, not all of the harvested sperm survives and fewer sperm to fertilize the eggs can result in a smaller litter.
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