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What Determines Litter Size in Dogs?

Adrienne is a certified dog trainer, former veterinary assistant, and author of the online dog training course "Brain Training for Dogs."

How many puppies are in a litter?

How many puppies are in a litter?

Dog Litter Size Determination

Determining the litter size of your dog can be helpful in many ways. For starters, it's important for the mother dog's health. If the litter is determined to be too large, it may cause dystocia, the medical term used to depict birthing complications.

Secondly, knowing in advance the number of the litter may help reputable breeders determine how many puppies will go out to their new homes. Responsible breeders should have a waiting list of potential future dog owners before the actual mating is scheduled.

Last but not least, knowing the litter size may help estimate income for those breeders who breed more for the money.

You may be planning a breeding and wondering how you can increase the size of the litter, or you may have bred already and wonder how you find out the size of the litter in advance. In this article, we will tackle both instances, starting with how you can up your chances for a larger litter.

Determining litter size in dogs

Determining litter size in dogs

How to Increase Litter Size in Dogs

The number of puppies your dam will have isn't just a casual happening depending on how the stars are aligned the day of the mating. Rather, you are in control of several factors responsible for dog litter size but may not be aware of it. Following are some factors that play a role in the dam's litter size.

Your Dog's Breed

Whether Fluffy has three puppies or ten depends for a good part on her breed. Some breeds are notorious for producing large litters, while several others are more on the conservative side. As a general rule of thumb, you should expect smaller litters in smaller dog breeds and larger litters in larger dog breeds.

According to a study involving 728,271 litters:

  • Labrador Retrievers were estimated to give birth to about 5–10 happy campers, with the average number being 7.
  • German Shepherds had between 5–9 with an average of 6.6. American Cocker Spaniels had between 3–7 with an average of 5.
  • Shetland Sheepdogs had anywhere in between 2–6 pups with an average of 4.3.
  • Yorkshire Terriers and Chihuahuas had 2–5 pups with an average of 3.3.

However, consider that some small breeds may still yield large litters; the Pekingese, for instance, may yield up to 10 puppies in a litter.

Your Dog's Age

Age has an effect on litter size. As your dam ages, you should expect a decrease in the number of puppies born compared to a younger dog. Generally, this decrease is noticed in dams of large breeds over the age of five. It is still not well known what causes this decrease, but it's speculated that it could be caused by a decreased number of follicles or an abnormality in the dam's uterine lining. It could also be due to premature embryonic death, causing fewer pups to make it to term.

However, don't get ready to celebrate yet; according to an article by Dr. Bretaigne Jones published for Royal Canin, very young females will also produce smaller litter sizes. So don't plan to breed that dam on her very first litter, she's not yet mature enough, and she will have a smaller litter compared to the average number for her breed. Generally, litter size increases steadily after each litter, with the largest litter generated generally at around the third or fourth litter. Afterward, expect a decline.

Your Dog's Health

If you want to be blessed with a large litter, make sure you keep your dam in optimal shape. Also, make sure the selected male is in good health. However, good looks and good temperament aren't the only factors to look at when breeding. It's also important to look at the dam's reproductive history by looking at previous litter size, milk production, and mothering capability, which are all heritable traits.

The healthier your dam, the more likely she'll be able to produce a litter based on her genetic potential. Nutrition will also play a role. Make sure your dam is neither too skinny or too fat. Consult with your vet on how to ensure your dam is fed an appropriate diet during gestation. Consider that during the last three weeks, you'll need to increase her feeding to almost two times her normal maintenance dosage.

Other Important Factors

Consider that there are other important factors to keep into consideration. According to the American Kennel Club, mother dogs give birth to larger litters in the spring and smaller litters in the summer. For more on this, read "What Time of the Year Are Most Puppies Born?"

The type of breeding may also have an impact. Generally, natural breeding appears to yield the greatest number of pups compared to dams that are artificially inseminated with fresh, chilled, or frozen semen. This is because during artificial insemination, sperm is most likely to die within the time frame of collection and insemination. The best outcome is by allowing the dam to be naturally bred two days after ovulation. Also, generally, the more inbred the dam, the smaller her litter size.

How many pups should I expect?

How many pups should I expect?

How to Determine Litter Size in Dogs

Determining litter size is a tricky business that requires some time.

Manual Palpation

While a vet may determine if a dam is pregnant by manual palpation as early as 28 to 35 days, this method is not good for determining litter size. At this stage, the puppies feel like little lumps ranging from grape size to ping-pong ball based on breed, but they shouldn't be handled much as they are very delicate developing embryos at this stage. Leave this task to the vet, but don't expect the vet to tell you litter size, just the good news that your dam is pregnant.


Ultrasound may sound like a good way to tell litter size. It can be done at around 25 days. At this point, it's a great way to tell if the dam is pregnant and the pups are alive and moving. This method, though, is not accurate for litter size as you are looking only at parts of the abdomen at a given time.


The best way to assess litter size is by radiography. This requires that the puppies' skeletons have mineralized, so they are visible on an x-ray. This mineralization process starts at around 45 days of gestation. This method is not 100 percent accurate, though, as the skeletons may be sitting on top of each other, making them a bit challenging to count. Yet, this is the best method as the skulls can be counted easily once the dam gets closer to whelping.

Are X-Rays Safe for Pregnant Dogs?

Determining litter size can help breeders tell if the mother dog has given birth to all puppies and recognize early signs of potential complications such as large puppies that may be hard to pass. However, it's also true that breeders may be concerned about having radiographs done in an expecting mother dog. While there's yet to be found literature proving that x-rays are a concern in late gestation in dogs, this definitively remains something to ponder about before proceeding.

This article is accurate and true to the best of the author’s knowledge. It is not meant to substitute for diagnosis, prognosis, treatment, prescription, or formal and individualized advice from a veterinary medical professional. Animals exhibiting signs and symptoms of distress should be seen by a veterinarian immediately.

Questions & Answers

Question: How many times do you need to breed the dam during the heat cycle?

Answer: Margaret Kutritz, a dog theriogenologist, suggests breeding every other day as long as the female dog is willing.


Carlos on June 29, 2020:

The dam can became pregnant if they play only in one day?

Celeste on June 22, 2020:

My dog is is starting her sixth week of pregnancy and is almost eight. This is her second time mating and she mated 5 times. Last litter she had eight puppies. Does how many times she mated effect her litter size?

Kelly Roberts Ontario on September 19, 2018:

We had a female inseminated this morning about 9:00. Our male has not been able to tie although he is 3 years old. At about 1:30 the male and female bred for the first time in our outdoor pen. Will this increase the size of the litter or would the second breeding not have enough sperm?

Adrienne Farricelli (author) on December 20, 2016:

Cynthia Fox, that's quite an interesting combination! Is the father of the pups much larger than your female? There are many things you can do to make her more comfortable such as feeding an appropriate diet, building her a nice whelping box, and keeping in touch with your vet throughout the pregnancy to ensure everything is going smoothly. There are also many books that can guide you through so to know what to expect. Best wishes!

Cynthia Fox on December 20, 2016:

Golly gee whiz

I have a female went into her second heat

She is shutzu/chihuahua

Father beagle/Pomeranian

I can not even imagine what these pups will look like

They are both in very great shape

What do I need to know or to do to make her comfortable through this pregnancy

Adrienne Farricelli (author) on June 16, 2013:

Awww.. thanks eiddwen, just finished taking a canine theriogenology college course and sharing a few interesting things I learned!

Eiddwen from Wales on June 15, 2013:

Interesting ad as always voted up. Your hard work has certainly paid off here alexadry.