Factors that determine the size of a litter

If you are planning to breed from your dog or are looking to buy a puppy, you might be interested to find out how large a litter can be expected from breeding. Knowing exactly how many puppies will ultimately be born is not something that you can be sure of until labour is completed, but there are a range of factors in play that go some way to determining the ultimate size of a litter, and we will explain some of them in this article.

The average size of a litter

There is really no such thing as an “average” litter size, and how many pups are born can vary considerably, even within the same breed or litters from the same dam. Medium sized and large dogs tend to produce the largest litters, with small and toy breeds tending to produce smaller ones, although there are exceptions! Anything from one or two puppies up to over ten is considered to be perfectly normal, and generally, dams will not produce litter sizes larger than they can manage.

Differences between breeds

As mentioned, there can be considerable differences between the sizes of litters of different breeds. While there is no firm guideline, dogs such as retrievers and spaniels will generally have litters of 4-8 pups, and smaller dogs such as the Yorkshire Terrier will have two or three.

The English Bulldog is a particularly interesting dog in terms of their litter sizes, as they tend to only have one or two puppies at a time, despite being stocky and well built dogs. The small litter size of the Bulldog, coupled with the fact that most Bulldogs require costly caesarean section delivery, largely dictates the value of the subsequent puppies, and goes some way to explain why Bulldog puppies are generally significantly more expensive than other pedigree puppies from similar sized breeds.

Factors that influence the size of the litter

There are a range of factors in play that can influence how large the litter will turn out to be, and the litter size will be dictated by both the dam and the sire.

The age of the dam is one of the main factors that influences litter size; young dams and dams over seven will tend to have smaller litters than adult dogs that have not yet reached old age. The age of the sire also affects the litter size, although to a lesser extent. The first litter for any given dam is also likely to be smaller than any subsequent litters.

The over all health of both parent dogs also comes into play; both dogs should of course be in excellent health and at peak fitness, and any dog that is not quite on the top of their game will tend to have smaller litters. Matings from limited gene pools, such as in the case of selective inbreeding or when dogs come from a smaller breed grouping where there is a limited amount of genetic diversity will tend to have smaller litters too.

Nutrition also plays a part in the size of a litter; the period of gestation and feeding the puppies after they are born places a lot of demands on the dam of the litter, and in order to be able to successfully achieve this, the dam should be of a healthy weight and fed an appropriate diet. If the dam is underweight or not receiving all of the nutrients that she needs, her litter will be smaller, and possibly less healthy overall.

Finding out the litter size once conception has occurred

The period of gestation for dogs varies from breed to breed, but is generally between 58 and 68 days. It is not possible to feel the individual puppies inside of the dam until the period of gestation is at least half way through, and even then it can be difficult to count the puppies with any accuracy! Ultrasound examination of the dog can give a fairly accurate picture of the size of the litter once the third week of pregnancy has passed, and this can be a useful tool for professional breeders who may have a waiting list for their potential puppies.

However, unless complications are expected or there appears to be a problem with the pregnancy, most hobbyist breeders will not undertake ultrasound examination, due to the cost involved.

Overly large litters

While larger litters are generally preferred by professional breeders as the number of pups in the litter ultimately dictates the availability to buyers, overly large litters can come with problems of their own. Litters of over eight pups are considered to be large, and over ten is rare, although up to seventeen live births have been recorded in some cases!

Overly large litters may lead to problems with delivery due to exhaustion, and the possibility of stillborn pups. Having a significant amount of puppies for the dam to feed after the birth can also pose problems, in terms of presenting difficulties with nursing all of the puppies, and ensuring that the dam stays hydrated and eats enough to support all of the puppies.