If your dog is pregnant, it's important to know how many puppies she is expecting. Knowing how many puppies are coming tells you how many new homes you'll have to find for the pups. It also lets you know if your dog fails to deliver all of her puppies and needs a vet to intervene in the birth. There are several ways to try and determine how many puppies are on the way, but most do involve a bit of guesswork.
Why litter size matters
When a small dog has a big litter, the risk of complications during the pregnancy and at birth increases. Knowing how many puppies your dog is expecting will help you and your vet devise a safe birthing plan for her. Getting an idea of how many puppies are coming also ensures that you provide your dog with a large enough whelping box to fit the young family comfortably in the first few weeks and lets you stock up on puppy supplies.
Dog litter size by breed
Breed plays a large role in a dog's litter size. Although there are individuals who step outside the norm, the general rule is that large breeds produce more puppies per litter than small ones. A Bullmastiff, for instance, can have a litter of five to 13 puppies, while a Yorkie is likely to have only two to five puppies at a time.
There are, however, exceptions to this rule. Even though they're small, it's not uncommon for Pekingese mothers to have litters of up to 10 puppies.
Your dog's age and health
When a dog reaches sexual maturity and breeds for the first time, she is likely to have a smaller litter than normal. After this first litter, however, dogs generally have increasingly larger litters until they reach the age of five. You can successfully breed a six-year-old dog, but she will likely produce a slightly smaller litter than she has in the past.
Like age, your dog's overall health also affects litter size. To increase the odds of a larger litter, make sure your dog stays at her optimal weight and has a nutritious diet. It's also important to make sure she gets enough food as her pregnancy progresses and she shares her nutritional resources with her growing puppies.
Reproductive history matters
A dog's first litter is likely to be a small one, but the number of puppies she has will grow with each subsequent pregnancy. Dogs typically birth their largest litter the third or fourth time they get pregnant. After that, litters tend to get smaller with every successful mating. A Chihuahua giving birth for the first time, for example, will probably have a smaller litter of Chihuahua puppies than a Chihuahua on her fourth batch of puppies.
The impact of immaculate conception
If you wish to breed your dog, you can either introduce her to a suitable male and let nature take its course or artificially inseminate her. Both methods work, but natural insemination tends to produce larger litters. Smaller litters occur in artificial insemination because some sperm cells inevitably die during the collection, storage, and insemination processes.
Although it produces smaller litters, artificial insemination is an excellent way to breed an uncooperative female who dislikes her chosen mate for some reason. It also allows deceased dogs with excellent personalities and breed characteristics to sire additional generations after their passing. If you have concerns over how your dog will handle a large litter, artificial insemination can help you control litter size and keep things more manageable.
The nipple myth
There is a popular notion that counting a dog's nipples will tell you how many puppies she will have. The theory goes that a pregnant dog will have half as many puppies as she has nipples so that every puppy can eat his share even if one or two nipples fail to produce enough milk. Most dogs have eight to 10 nipples and an average litter size of about five puppies, making the theory appear true.
In reality, however, this is pure coincidence and has no scientific backing. In fact, a Neopolitan Mastiff named Tia set a world record in 2004 by delivering 24 puppies in one litter. Tia certainly didn't have 48 nipples! In this case, it's important to remember that correlation and causation aren't one and the same.
Feeling for puppies
There are clearly many ways to estimate how many puppies your dog will have, but things get a bit trickier when you want a more precise count. One way to try and get one is to feel the dog's uterus and try to count the babies. You can start to feel puppies about 25 to 28 days into the pregnancy, but counting them is still difficult since they feel like little lumps or grapes.
Because they're so small, it's easy to miss a puppy or two when feeling for them. It's also potentially dangerous, as squeezing too hard can damage the tiny embryos. When trying to count puppies by feel, leave the job to your vet so you don't accidentally harm a puppy. Take the number he gives you with a grain of salt, however, as even a professional can miscount at this stage.
Going for an ultrasound
When your dog's pregnancy reaches the 25-day mark, your vet may suggest an ultrasound to count her puppies. An ultrasound machine uses sound waves to generate a picture of your dog's uterus so the vet can count her puppies.
Ultrasound is perfectly safe for both the mother dog and her unborn puppies, but like palpation, it's not foolproof. If the puppies position themselves above or behind one another, the ultrasound may show one puppy when there are really two. Again, the number your vet gives you is an estimate rather than a fact. Vets sometimes use ultrasound only to confirm pregnancy rather than trying to count them.
Getting a headcount
The best way to get an accurate count of how many puppies you're expecting is through an X-ray. At around 45 days of gestation, the puppies' bones start to harden and mineralize, making it possible to see them on an X-ray. Your vet can then count the number of skulls or spinal cords present in the uterus to get a more accurate puppy count.
Although skeletal mineralization begins around day 45, many vets will wait until day 55 to take an X-ray. This gives the puppies' bones time to fully harden and provides the most accurate count. It also means taking only one X-ray late in the pregnancy, minimizing the unborn puppies' radiation exposure. This also allows the vet to make sure the puppies are all in the proper position for a complication-free birth.
Even with an X-ray, however, a miscount is still possible. Growing puppies start running out of room in the womb and end up huddled close together. Depending on how they're aligned, one or two pups could hide from the X-ray machine.
- Oakland Veterinary Referral Services: Pupternity: What Determines Litter Size in Dogs?
- PetHelpful: What Determines Litter Size in Dogs?
- American Kennel Club: Deciding on the Best Method of Artificial Insemination
- K9 of Mine: How Many Puppies Can a Dog Have?
- Guiness World Records: Largest Litter - Dog
- Today's Veterinary Practice: Fetal Count Radiology
- East Central Veterinary Hospital: Canine Pregnancy