Artificially inseminated prey produce smaller litters than naturally impregnated prey. This is probably due to more sperm dying during collection and insemination. Another key factor affecting size is when a mother gives birth to a litter of puppies. The simple answer is that yes, genetics can affect litter size.
In fact, it can affect litter size by up to 15%. In addition, many other aspects of reproduction, such as problems with childbirth and even lack of interest during mating, can be affected by genetics. In general, litter size increases with any type of semen if deposited directly in the uterus; in a Scandinavian study, the average litter size was 4.0 pups for vaginal insemination, compared to 5.4 pups with intrauterine insemination. Usually, the size of a dog litter is mainly based on the size of the dog's body simply because biologically, larger bodies are capable of carrying a larger litter than smaller bodies.
The goal of most breeders is to produce litters of average size or above average so that they have a greater selection of puppies to choose from for their kennel. Instead, this article will focus on the proven causes of decreased litter size in female dogs, to help you and your veterinarian better determine when a pathological cause may be present to decrease litter size. The characteristic of larger dog breeds having larger litters is not new; this phenomenon is consistent with other studies. One perspective is to observe what can influence the size of a litter; another is to study the litters of a puppy.
Since there was no body of literature on this topic, several breeders and veterinarians who had reported experiences with individual puppy litters were contacted. Let's say that for your breed the average litter size is between 8 and 12 puppies, some breeders want to help their mother reach 11, 12 or even 13 puppies. However, that's not the case and, like everything with breeding, it's very important to understand the science of litter size. Larger litters will most likely occur when the male dog is less than 5 years old, since it is easier for sperm to enter the female's eggs and most sperm are of higher quality.
While many species have single births, canines are not one of them, although there are many breeds that only produce one or two litters of puppies. In conclusion, as a breeder it is important to consider all of the above when trying to determine the cause of the low litter size in a given dog or in her kennel. Small litters can be directly related to the selective breeding practices that breeders have used over the years to meet the physical size requirements of their breed standards. Breed size, dog age, and mating method are three factors that work together to determine litter size.