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Dog Word of the Day: Runt of the Litter

In a litter of puppies, it's not unusual for there to be what's known as the "runt of the litter." The world of literature and animated movies is populated by many famous runts. If you recall as a child reading the book "Charlotte's Web or watching the animated version of the novel, you'll likely recall that Wilbur was the runt of the litter and was at risk for being slaughtered, while Clifford the Big Red Dog, was also a runt who managed to grow explosively until he became 25 feet tall. Not to mention Babe, the piglet hero from Dick King-Smith's book, but what exactly is a "runt of the litter" and why are they born this way? Also what can be done to help runts survive? Fortunately nowadays, puppies who are runts of the litter have a higher chance of survival courtesy of the care provided by their humans.


What is a Puppy Runt of the Litter?

Among a litter of puppies, the runt of the litter is a puppy that is smaller and weaker than the others. However, just because a puppy is smaller than the rest that doesn't officially make him a runt and not all litters have runts.

After all, just because your brother is 6 foot tall and you are just 5.6 doesn't make you a runt, does it?

A better definition for runt would perhaps be a pup that is abnormally small for his breed and age and that is struggling to flourish due to health issues. However, there doesn't seem to be any real, clear cut official definition for this term.

Runts generally face several disadvantages when compared to the rest of the litter. Puppies that are runts generally have a harder time competing with their siblings for milk and sometimes they may also be rejected by mother dog who senses something wrong with the puppy and instinctively caters her energies to the stronger puppies. Runts also typically struggle with health ailments which can range from mild to even severe and life threatening.

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With a rough start and rejection from the mother, in the wild, runts tend to struggle and often fail to survive; however, in a domesticated setting, runts are often able to, not only survive, but even thrive, courtesy of some TLC provided by their caretakers. After all, runts of the litter, tend to evoke nurturing instincts in humans, so it's not surprising to be drawn to these little fellows! Many caretakers confess that helping out runts and watching them grow bigger and stronger can be quite a rewarding experience!

"There is really no agreement among veterinarians – or anyone else for that matter - as to what constitutes a runt." Dr. Ron Hines

What Makes a Dog the Runt of the Litter?

chihuahua puppy

A common myth that floats a lot around breeding circles is that runts are puppies who were in the middle of the uterus or who came from eggs that were conceived last.

In reality, when the dam releases her eggs to be fertilized, they are actually released all at once generally over a 24 hour span.

Even if say a puppy was conceived later than the other puppies, there are still 17 days during which they float freely before implantation and the formation of the placenta, explains Dr. Margaret V. Root Kustritz in her book "The Dog Breeder's Guide to Successful Breeding and Health Management." This means that all the pups are ultimately of the same age, but runts may have undergone what's known as "poor placentation."

What does poor placentation mean? It means that basically, during gestation, runts may have had a poor implant site in mother dog's uterus. Perhaps there was an old placenta scar and the area of implantation did not have a rich blood supply.

A poor vascular system may therefore fail to provide the ideal blood supply that is needed for the developing puppy. Runts are not therefore, premature puppies; rather, they are simply puppies who happened to have a poor implantation site, while large pups had a better one.

"What accounts for runts is not being fertilized later than the other eggs, it is their placement within the uterine horn. "~ Myra Savant-Harris


Coming to the Rescue

Because runts are small and weak, mother dog may reject tending them with the care as they would with stronger puppies. Mother dog may reject them straight off the bat right when they are born, or shortly thereafter.

This means that human intervention may be necessary in order to help the puppy survive. Puppy owners may therefore have to free the puppy from the amniotic sac, massage him to increase circulation, clear his airways and then remove the puppy's umbilical cord. Runts may also need assistance with staying warm, clean and well-fed.

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Puppies who are runts often struggle to compete with the stronger puppies. This can cause them to miss out on nursing as they should. Failure to nurse properly can have quite an impact on the puppy's health, especially considering that mother dogs produce a special milk known as colostrum only for the first 48 hours.

This special milk is rich in antibodies that will help protect the puppies from diseases for their first few weeks when they are most vulnerable.

If a runt misses out on reaping the benefits of receiving this milk, his immune system may not be strong which can ultimately lead to illness. It's important therefore that these pups are given the opportunity to nurse and if they appear to not want to nurse, a puppy milk replacer may help out or a veterinarian should be consulted for advice.

Tip: runts may not have the same energy to nurse with vigor as the other puppies. It may help to let another puppy nurse first so to increase the milk flow to a particular nipple, then move this puppy away and let the runt use the nipple so that milk flows freely.

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dog pain goes away at the vet

The Health of Runts 

When a runt of the litter is born, it's important to find out whether there is some congenital defect of some sort or genetic abnormality causing the puppy to not flourish and gain weight as the others. Getting a daily weight of the pups is paramount so to ensure they are growing at a steady pace.

While all new puppy owners are advised to have their new puppies undergo a vet check in the first day or two, it's even more imperative with a runt if the litter puppy that is smaller than usual.

It's therefore not a bad idea to consult with the breeder about the option of having the puppy see the vet and then making arrangements such as reimbursement of veterinary bills or returning the puppy based on the vet's findings.

The veterinarian may help determine whether there is an underlying health problem. Sometimes, runts are underdeveloped in other ways than just size. For example, a portosystemic shunt (or liver shunt) can be seen in a puppy who has trouble gaining weight, but this is usually seen in small dog breeds and there are often signs of poor appetite. Also, being loaded with parasites may also play a role in causing failure to gain weight but this is usually not dramatic, explains veterinarian Dr. Marie.  Other potential problems to check for include heart defects and cleft palates.

"The runts of the litter can have heart defects and other congenital problems including umbilical hernias that the breeder might not disclose to you so it's a good idea to have your veterinarian do a complete examination of the puppy before you agree to buy the pup (or have a refund if there is a congenital problem). Good respected breeders will understand and expect this but unfortunately there are a lot of people trying to make an easy buck."~Dr. Jan

blue nose pit bull scam

Puppy Runt of the Litter Price

And what about price? Just because a puppy is a bit slower to develop compared to the other puppies, doesn't mean he should cost less than the other puppies as long as he's healthy.

Many smaller runt if the litter puppies grow up to be the same size, (if not even larger!) than the other pups.

Some unethical breeders may charge a premium for runts in small breed dogs and call them with the flashy name of "teacup dog breeds."

Ethical breeders, on the other hand, will never use a true runt as a candidate for breeding and therefore will sell them for a normal price as their other puppies along with a strict spay or neuter contract.

"The small size does not necessarily mean that the runt of the litter will not be a good pet if all other health issues are within expected limits."~ Dr. Robert L. Ridgway


  • The Dog Breeder's Guide to Successful Breeding and Health Management. by Margaret V. Root Kustritz DVM PhD DACT Saunders; 1 edition (December 23, 2005)
  • Canine Reproduction and Whelping: A Dog Breeder's Guide, By Myra Savant-Harris, Dogwise Ebooks (January 1, 2006)

Photo Credits:

Flickr Creative Commons, Wendy Berry, Little Runt, He doesn't even want the milk. He's just wants to nurse on something, anything.

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