Does Litter Size Affect Puppy Size?

Dog litter sizes vary from one puppy to more than a dozen newborns. The recorded largest litter had 24 from Neapolitan mastiff, a very large dog breed. While litter size can impact many aspects of whelping and raising puppies, it does not actually impact the size of the individual puppies. The parents' genes, the puppy's breed, and the mother's health and nutrition determine the puppies' size at birth. However, generally speaking, dog breeds with large litters tend to be the larger breed dogs.

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One of the biggest factors in litter size is breed. Small-breed dogs, such as Chihuahuas, do not have room in their bodies for large litters, therefore they tend to produce only two to four puppies per pregnancy. Large-breed dogs, such as great Danes, usually have larger litters, 10 to 12 puppies being common. Other dog breeds with large litters include German shepherds and golden retrievers which have an average of eight puppies per litter.

Breed type also impacts the size of the newborns. Small-breed puppies are typically several inches smaller than large-breed puppies, regardless of the number of dogs in the litter. A normal litter size can range from one to 12 puppies, and five to six puppies is the average little size for most dogs. However, it possible dogs to have a litter of just one puppy.

Unusually small puppies are not a result of large litters. Instead, their size can usually be traced back to the health and nutrition of the mother dog before and during her pregnancy. Because the unborn puppies share the nutrition the mother dog takes in from her food, she needs an ample diet to properly nourish the puppies.

Without sufficient food, the puppies will not reach appropriate size and can suffer health problems. If prenatal care, nutrition, and proper vitamins are important for humans, that's important for dogs too. Proper nutritional care should start long before the female dog is bred. Most puppies that die soon after birth were probably born from malnourished mothers.

Even though litter size does not impact individual puppy size, large litters can cause problems for the mother dog and her new babies. If the mother's uterus attempts to carry more puppies than she can physically handle, her life and the puppies' lives can be threatened. Also, large litters tend to produce more stillborn puppies and runts.

With so many neonatal puppies vying for nutrition, those in the center of the womb often do not get sufficient nourishment, which can cause them to be born small or to die. Large litters can trigger earlier-than-expected whelping, which can be a problem for the puppies' unprepared human parents.

While accurately predicting the size of an expectant mom's litter is difficult, some other factors do contribute. Research shows older mother dogs have smaller litters than younger canine moms. Also, dogs who had their first litter at an older age will have smaller litters. The age of the male dog, or sire, can make a difference as well. After five years, sperm count diminishes, so the number of eggs a sire might fertilize might also be less, leading to a smaller litter size.

The mother dog's weight can be also be a factor. Obese female dogs tend to have smaller litters than healthy-weight dogs. However, any pregnant female can experience a large litter relative to normal within her breed. A veterinarian can do an ultrasound to estimate the size of the litter so the household can prepare adequately for the new arrivals.