The Science of Dog Litter Size

🇫🇷 Lire en Français | 🇪🇸Leer en Español | 🇧🇷Leia em português

Have you ever wondered what factors determine the size of a litter of puppies and how it can impact both the safety of the newborns and the well-being of the mother? As a breeder or veterinarian, it is crucial to understand the interplay between maternal factors and litter size, as it can have significant consequences.

In this comprehensive blog, we delve into the science behind the relationship between maternal age, breed, and breeding method, and the impact they have on the average litter size of dogs. So, grab a cup of coffee and join us as we explore the fascinating world of canine breeding and learn about the critical importance of litter size.

“The litter size directly affects the safety of puppies during birth and depends on the mother’s age, breed, and the breeding method.”

Uchańska et al, 2022

When a dam gives birth, the group of newborn puppies is known as a ‘puppy litter.’ These litters can vary remarkably in size, from just one or two pups to a bustling group of twelve or more. Understanding the average litter size is crucial for dog breeders and pet enthusiasts, as it influences expectations, preparations, and overall care strategies.

I am on a mission to learn everything about dog and cat breeding. Sign up to my newsletter to follow my journey, and receive exclusive content and offers!

What Determines a Dog Litter Size?

The average litter size generally hovers around five to six puppies, but this number is far from set in stone. Canine litter size variation is a fascinating phenomenon, truly influenced by a myriad of factors:

Genetic and Breed-Specific Factors

Breed Size:

Breed size is a major player in the canine litter size variation we observe across different types of dogs. Typically, larger breeds such as Great Danes or St. Bernards have the genetic propensity to produce larger litters, often because they have more space to accommodate more offspring. On the flip side, smaller breeds like the Pomeranian often have fewer puppies. The genetics that dictate breed size also set the stage for the number of puppies a dam can carry.

For example:

Great Danes, one of the largest dog breeds, can have litters with as many as 10 puppies, although the average is about 8. The largest litter I have seen in my career was actually in a Great Dane: she delivered a whooping 20 puppies!

Mastiffs, another giant breed, are known for litters that can range from 6 to 10 puppies on average, but there have been cases where a Mastiff has had up to 16 puppies.

Labrador Retrievers, which fall into the medium to large breed category, typically have litters of 5 to 10 puppies, with an average of 7 to 8.

Golden Retrievers are similar in size to Labradors and usually have litters of about 8 puppies, but litters of up to 12 are not uncommon.

In contrast, smaller breeds often have fewer puppies per litter:

Chihuahuas, one of the smallest breeds, may only have 1 to 3 puppies in a litter. On occasion, they might have a litter of up to 5 or 6, but this is less common. That being said, the largest litter I have seen in Chihuahuas was 9 puppies!

Dachshunds typically have litters of about 3 to 4 puppies, although due to their elongated body, larger litters can be risky for the dam.

Pugs, also a smaller breed, usually have litters of 4 to 6 puppies.

Shih Tzus have litters that range on average from 2 to 5 puppies.

Genetic Factors:

Certain genes can influence the number of offspring. The genetic makeup of a female dog can significantly impact her potential litter size, with some females naturally predisposing to ovulate more eggs during each estrus cycle. The number of eggs ovulated is indeed the biological foundation that determines the maximum possible size of the litter. If more eggs are released and subsequently fertilized, the larger the litter can potentially be.

In practice, you might notice that certain “lines”within a breed tend to be more prolific than others. This could be attributed to the strong hereditary factors that run in specific lineages. For instance, if a lineage has consistently produced larger litters, it’s likely that this trait is being passed down through generations, suggesting a genetic predisposition for higher fecundity.

And while it is clear that genetics plays a role in the number of offspring, the complex interaction of multiple genes makes it challenging to pinpoint exact genetic markers.

Inbreeding vs. Outcrossing

Genetic diversity can have a significant impact; inbreeding may decrease litter size due to genetic disorders, while outcrossing may increase it.

Inbreeding, in its simplest terms, is the breeding of animals that are closely related, such as brother and sister, parent and offspring, or cousins. This practice is often used intentionally in animal breeding to maintain certain desirable traits or characteristics that are found within a particular family or lineage.

In the context of purebred dog breeding, inbreeding occurs to some degree because all purebred dogs are part of a closed gene pool. That is, to be considered a purebred, a dog must have parents that are of the same breed, which means their genetic makeup is quite similar. Since purebred dogs are bred to meet specific breed standards, there is often a limited number of dogs that can be used for breeding without introducing traits considered undesirable for that breed. As a result, purebred dog breeders are, in effect, engaging in a form of inbreeding, even if it’s not as direct as mating immediate family members.

The key thing to remember is that inbreeding itself is not inherently “evil” or bad; it is a tool that has been used in many animal breeding programs, including those for dogs, to select and strengthen certain traits. For example, if a breeder is aiming to ensure that all of their puppies have a certain coat colour, size, or temperament that is valued in their breed, they might choose to breed dogs that are related because they carry these desired traits.

The disparity in litter size is of particular concern in larger breed dogs

However, it is crucial to approach inbreeding with caution because it can also concentrate harmful genetic traits and increase the likelihood of genetic disorders. Responsible breeders use inbreeding carefully and often employ strategies such as outcrossing (breeding to unrelated dogs) or line breeding (breeding to more distantly related individuals) to maintain genetic diversity and reduce the risks associated with inbreeding.

And in the end, I think this is a key take-away everyone should remember here: maintaining genetic diversity is a crucial aspect of responsible dog breeding. These days, this is an important part of the discussion I have with dog breeders when talking about infertility.

The emergence of genetic testing has revolutionized how breeders can approach the breeding process, making it more informed and responsible.

We now have tests that offer breeders the ability to understand the genetic diversity between two potential breeding partners. In the past, we used to calculate Coefficients of Inbreeding (COI) to gauge the genetic diversity, we wanted them to be below 25%… However, they sketched out only the outlines of a much larger canvas.

Evidence suggests that genetic diversity tests can improve fertility, often leading to larger litters.

👉🏽I believe it is essential for breeders to evaluate the genetic diversity of the dogs they plan to breed, as research has shown that increased genetic diversity enhances reproductive performance, including fertility. Here is the test I recommend for assessing genetic diversity in breeding dogs.

Breeding age plays a crucial role in a dog’s reproductive health and the size of her litters. Young dams in their prime typically have more robust fertility, which can lead to larger litters. As a dam ages, however, her fertility naturally declines, often resulting in smaller litters. This shift in reproductive capability is a natural part of the canine life cycle.

Female Dog’s Age:

Younger dogs typically have smaller litters; as they mature, litter size can increase until it plateaus and eventually decreases as they become older. For breeders and veterinarians alike, understanding the impact of a mother’s age on litter size is crucial.

The fertility and reproductive health of a dog can greatly be influenced by their age, with those less than 1 year or over 6 years old having fewer pups compared to dogs aged 2 to 5 years.

Unfortunately, older primiparous bitches are at a higher risk for single-puppy pregnancies, uterine disorders, prolonged labor, and even dystocia (= difficulty to give birth).

Thus, breeding bitches over the age of 6 is highly discouraged for the health and well-being of both the mother and her litter.

Male Dog’s Age:

Age is a significant factor in canine fertility, not just for females but for males as well. As male dogs grow older, they become more susceptible to various reproductive disorders, with prostatic disorders being particularly common. It is estimated that nearly 80% of male dogs over the age of 8 will develop benign prostatic hyperplasia (BPH), which is an enlargement of the prostate gland.

Although BPH is often asymptomatic, meaning it does not present noticeable symptoms, it can have a profound impact on a male dog’s breeding capabilities. The condition can alter the prostate’s secretions (which represent 90% of the total volume of a dog’s ejaculate), which in turn may adversely affect the quality of semen.

However, assessing fertility based on age alone can be misleading. The range of fertility in male dogs is wide and varied. For instance, I have seen some young dogs, as early as two years of age, exhibiting poor semen quality, whereas much older dogs – I remember one 16 year old especially – producing sperm of exceptional quality. This unpredictability underlines the fact that there’s no universal standard when it comes to fertility related to age.

The definitive method to evaluate a male dog’s fertility is through a spermogram, an analysis of semen that assesses various parameters such as sperm count, motility, and morphology.

Conducting a spermogram provides a clear picture of the reproductive status of a stud dog. For breeders, regularly scheduling spermograms (every 6 months) for their stud dogs is a crucial step, ensuring that any decline in semen quality is identified promptly and managed accordingly.

Individual Health of the Female:

Here is a foundational principle that must always be at the forefront when it comes to dog breeding: the health of the dam.

Indeed, the dam’s overall health is a critical determinant of her reproductive capacity. Any existing medical conditions can have a direct impact on her ability to conceive, carry a pregnancy to term, and deliver a healthy litter.

Therefore, it’s paramount to ensure that the dam is in optimal health before breeding.

Health of the Reproductive Tract

Reproductive health is an umbrella term that encompasses the myriad factors impacting a dam’s ability to conceive and sustain a pregnancy to term. Maternal health in dogs, including her hormonal balance, nutrition, and the presence of any underlying medical conditions, plays a pivotal role in the size of her litters. A healthy dam with a robust reproductive system is more likely to have larger litters compared to a dam with health challenges.

Among infectious causes to remember here, canine brucellosis stands out as a particularly noteworthy concern. This is the one you MUST remember in my opinion. Especially as this bacterial infection is seeing a resurgence in areas of Europe and North America. It’s a stealthy adversary for dog breeders as it can lead to infertility, miscarriages, and reduced litter sizes. Knowledge and vigilance about canine brucellosis are imperative for breeders to prevent its spread and protect the reproductive health of their dogs.

Turning to the topic of genital tract abnormalities, uterine disorders emerge as a predominant issue. Regular health check-ups to screen for such disorders are essential. While pyometra—a severe uterine infection—is often top of mind, it’s the subtler conditions like subclinical endometritis that can be the true culprits in impairing fertility. My time at the veterinary school in Paris was partly dedicated to studying subclinical endometritis, a lurking inflammation of the uterus lining that may not show overt clinical signs but can thwart the establishment and maintenance of pregnancy. This is one I think dog breeders should also always have in mind these days, as it is often overlooked as a cause of infertility and small litter size actually.

Another concern that should not be overlooked is ovarian cysts. These formations on the ovaries can manifest in various ways and might disrupt the normal estrous cycle of the female, leading to irregularities in ovulation and, consequently, fertility challenges. The likelihood of cyst development can increase with age, making regular reproductive assessments an important routine for aging females in a breeding program.

Nutritional and Physical Conditions

Body Condition

Overweight or underweight dogs may have reduced fertility, affecting litter size.

The connection between a dog’s body condition and its fertility is a significant factor that can influence litter size. A Body Condition Score (BCS) test is an invaluable tool I prioritize before breeding, as it assesses whether a dog is at its optimal weight—a pivotal aspect of reproductive health. My steadfast rule is to breed only those dogs that have an ideal body condition (which means a BCS of 4 or 5 on the 9-point scale I use there).

Excess weight can pose several reproductive challenges. Notably, an accumulation of fat can elevate the body’s core temperature, which in turn may induce what’s known as heat stress. This condition is detrimental as it can interfere with the normal reproductive cycles and processes.

Additionally, an overweight status means more fat infiltrating the uterine muscle, which can lead to a diminished strength of uterine contractions. These contractions are vital for a successful birthing process, and their impairment can contribute to increased neonatal mortality due to difficult births.

Moreover, it’s not just about the birth process itself; the condition of the mother also affects the puppies’ development. Recent studies have highlighted that overweight females often produce smaller puppies. These low birth-weight puppies are at a higher risk for neonatal mortality, as their underdeveloped condition makes them more vulnerable in the critical early stages of life.

Keeping a dog in peak physical condition is an essential part of responsible breeding practices, contributing to the well-being of both the mother and her puppies.

Nutritional Status

Both prior to and during pregnancy, proper nutrition is vital for a healthy litter size.

The concept of “flushing” is a fascinating one in animal reproduction. It refers to a specific feeding practice where the energy intake of the females is increased just prior to and during the breeding period. This is commonly done in other species like sheep to enhance ovulation rates, and subsequently, increase the chances of a larger litter size. The idea is that the extra nutrition will spur the body to release more eggs during ovulation.

In the case of canines, the practice of “flushing” is not widely recognized or understood in the same way. Dogs naturally ovulate multiple eggs, and it has been generally assumed that their ovulation rates—and by extension, their litter sizes—would not be significantly impacted by such a feeding strategy. Nonetheless, this is an area that could benefit from more scientific research to understand if there is a beneficial application of “flushing” in dogs.

Nutrition during gestation in dogs and cats

However, as mentioned earlier, maintaining an optimal body condition is key. This is something you should always keep in mind here! Until around day 42 of a dog’s gestation, there’s no need to increase the energy and nutrient intake.

The developing puppies gain approximately 70% of their final birth weight in the last third of gestation. Therefore, it is from day 42 onwards that the diet should be adjusted to a higher energy density, typically switching to a puppy-formulated diet to support this critical growth phase. Overfeeding before this point is counterproductive. Excessive energy will likely be stored as fat, which can negatively affect the reproductive functions and the ease of birth (whelping).

The same caution applies to supplements. It’s essential to ensure they don’t inadvertently lead to an increase in the dam’s body condition score. A balanced approach to nutrition supports fertility and optimizes litter size, underscoring the importance of a well-planned diet for pregnant bitches.

👉🏽For the first part of gestation (0 to 42 days), this is the diet I recommend for small and large dogs. For the second part of gestation and throughout lactation, this is the diet I recommend for small, medium, large, and giant dogs.

These nutritional solutions are also available through a breeder program. Learn more about options in the USA and Canada.

Reproductive Health and Management

Timing of Ovulation

Accurate timing to coincide with peak fertility is crucial for maximizing litter size.

Timing of ovulation in dogs

The process of breeding dogs is both an art and a science, with timing being an essential component of the latter. A lack of understanding of a dog’s reproductive physiology can lead to the common issue of breeding at the wrong time, which is the leading cause of poor fertility outcomes in dogs. Just as critical to fertility is the influence of accurate timing on litter size.

Dogs have a unique reproductive cycle. Pinpointing the optimal time for breeding is not merely beneficial but necessary for enhancing both the likelihood of conception and the potential litter size.

Among the various methods used to determine the best time for breeding, progesterone testing is widely recognized as the gold standard. This hormone, which rises sharply in the blood as ovulation approaches, is a reliable indicator of a bitch’s fertility status. By tracking progesterone levels, breeders can identify the peak fertile period and plan the breeding accordingly.

While some breeders may attempt to use other signs or methods to predict ovulation—from physical changes to behavior patterns—these are often less accurate and can lead to the aforementioned problems of mistiming. In contrast, regular progesterone testing during a bitch’s heat cycle offers a scientific and precise approach to breeding timing.

Different techniques one can use to perform timing of ovulation in dogs

It’s not just about catching the right day; it’s about unlocking the full reproductive potential of the breeding pair. With each cycle being a crucial opportunity, no breeder should overlook the importance of progesterone testing. Doing so can maximize the chances of a successful mating and, consequently, a larger, healthier litter.

Semen Quality of the Male

The health and motility of the sperm can significantly impact conception rates… and litter size subsequently.

The success of dog breeding hinges not only on the health of the female but equally on the vitality and quality of the male’s sperm. Earlier, we discussed the impact of age on a male dog’s fertility, highlighting that disorders like benign prostatic hyperplasia can influence semen quality, thereby affecting fertility and potentially litter size.

A spermogram, an analysis of semen health, therefore emerges as a pivotal test in this context. By assessing various parameters such as motility, sperm count, and morphology, a spermogram provides a comprehensive overview of the male’s reproductive health. This evaluation is indispensable because while a female dog’s readiness for breeding is crucial, the male’s ability to provide healthy, motile sperm is equally fundamental to achieving conception and ensuring the desired litter size.

It’s important to remember that fertility and, by extension, the resulting litter size, are the outcomes of combined male and female reproductive health. For optimal breeding results, both partners must be at their peak reproductive efficiency. Regular spermograms can help ensure that the male’s semen quality remains conducive to successful breeding.

Reproductive Health History

Previous pregnancies and their outcomes can impact future litter sizes.

The history of a bitch’s previous pregnancies and their outcomes is a significant indicator of her future breeding potential. Each birthing process leaves a physical impact on the uterus, primarily due to the type of placentation in dogs, which can cause micro-lesions. These lesions may predispose the bitch to uterine health issues such as subclinical endometritis, which can arise unnoticed but still significantly affect fertility.

My favourite approach would be to perform genital ultrasounds before any breeding attempt, assessing the uterus and ovaries for any potential health issues. This step is particularly crucial for bitches with a history of infertility or prior birthing complications, as it allows breeders to anticipate and manage possible reproductive challenges.

In the same line of ideas, proper reproductive hormone levels are fundamental to ensuring that ovulation and implantation processes occur correctly. Progesterone is THE hormone to remember here. Disruption in the hormonal milieu can lead to irregularities in the estrous cycle, affecting the timing and quality of ovulation, which in turn impacts litter size.

When a timing of ovulation is performed, this is actually something that can be monitored… and this monitoring could expand during gestation as well in cases with a history of infertility or reproductive issues. This kind of monitoring actually allows us veterinarians to detect anomalies in the ovulation process, which diminishes the chances of a larger litter. Think especially ovarian cysts here.

Environmental and Stress Factors

Environmental Conditions

Stressful conditions can adversely affect the fertility of both the male and female.

Stressful conditions indeed pose a significant threat to the reproductive health of both male and female dogs. Stress triggers the release of cortisol, a hormone that, while necessary for some bodily functions, can be detrimental when present at high levels. Excessive cortisol directly interferes with the reproductive system, disrupting normal hormone balances that are crucial for fertility.

In females, heightened cortisol levels have been linked to disruptions in the estrous cycle, which can lead to irregular ovulation times or even anovulatory cycles, where no ovulation occurs. This not only reduces the chances of conception but also, if pregnancy has already been established, can create an environment that increases the risk of miscarriage or spontaneous abortion. Cortisol can have an inhibitory effect on the uterine environment, affecting embryo implantation and stability.

In males, stress and the consequent surge in cortisol can impair spermatogenesis, the process of sperm production, and reduce sperm quality and motility. This decline in semen quality can significantly lower conception rates.

To avoid the adverse effects of stress and optimize fertility, it is imperative to maintain a calm and stable environment for breeding dogs. This means routine, a quiet and safe space, and familiar practices to keep anxiety at bay. Ensuring dogs have a structured routine, regular exercise, and mental stimulation can help mitigate stress levels. In breeding situations, handling dogs with patience and care, minimizing their exposure to loud noises and unfamiliar situations, and providing them with a comforting presence are all practices that can promote a more tranquil state conducive to successful reproduction.

👉🏽I believe that pheromone diffusers are an excellent tool for reducing stress in breeding dogs, and studies have shown that they can significantly enhance maternal care in breeding females. Here is the pheromone diffuser I recommend for dogs.

Seasonality

Some evidence suggests that the season can influence fertility and litter size.

Seasonality in dog reproduction tends to be more prominently observed in certain primitive breeds. These breeds, such as the Basenjis and Tibetan Mastiffs, are known for their typically once-a-year heat cycles, which seem to align with specific seasons. This behavior is thought to be a holdover from their ancestors, where breeding during certain times of the year would increase the survival chances of the offspring.

The fertility and reproductive health of a dog can greatly be influenced by their age

However, in domesticated dogs, the influence of seasonality is less pronounced. In general practice, female dogs, regardless of breed, may come into heat throughout the year. Similarly, male dogs are capable of producing viable semen year-round. While environmental factors such as daylight hours and temperature may have some influence, inducing observable peaks in breeding activity, these are not rules that apply uniformly across all breeds or individuals.

I do remember observing an uptick in the number of females coming into season during certain times of the year, which could suggest a mild seasonal pattern in reproduction. However, the underlying mechanisms are not well understood and seem to be less relevant in a domestic context where dogs are often kept indoors and their environment is controlled.

Breeding Technique and Frequency

Frequency of Mating

The common belief that multiple matings can increase litter size in dogs is based on the desire to maximize the number of viable sperm to meet the available eggs. However, the efficacy of multiple matings isn’t about quantity as much as it is about timing and quality.

Sperm cells have a survival window of approximately 2 to 4 days within the female dog’s reproductive tract, whereas the eggs, once mature, are viable for about 48 hours. The critical aspect here is ensuring that viable sperm are present when the eggs are ready to be fertilized.

To optimize this overlap, performing a timing of ovulation is paramount. This is where progesterone testing becomes an invaluable tool for breeders, as it helps pinpoint the optimal breeding time.

Rather than indiscriminately increasing the number of matings, breeders are advised to aim for two well-timed matings, typically about 48 hours apart, coinciding with the post-ovulation period when the eggs are viable. This strategy is based on average sperm viability and should ideally result in successful fertilization of the eggs.

However, the approach can be tailored to specific circumstances. For example, if semen analysis (spermogram) reveals that the male dog has a lower semen quality, the veterinarian might suggest more frequent matings to increase the chances of fertilization. In such cases, the goal is to ensure a continuous presence of enough healthy sperm in the female’s reproductive tract to meet the eggs.

Ultimately, while multiple matings can be part of a strategic breeding approach, they are not a guarantee for a larger litter size. The focus should be on the timing of the mating to match the lifespan of the sperm with the viability of the eggs, and the overall health and fertility of both the male and female dogs.

Management of the Breeding Process

Professional oversight can enhance successful breeding outcomes. And professional oversight in dog breeding is not just beneficial; it’s often crucial.

Take for example this story with one of my former clients.

He had done a timing of ovulation for his female dog, so we were able to accurately determine the best breeding dates. However, despite this, the pregnancy diagnosis performed 3 weeks later revealed that the dog was not pregnant…

Upon discussing the potential reasons for this outcome, he told that he did not actually witness the mating. He had left the male and female dogs alone together, assuming nature would take its course while he stepped away for a coffee. As it turns out, his female dog was VERY dominant… which likely inhibited the mating process—she may have prevented the male from mounting.

To circumvent such issues, the next breeding attempt was managed differently. Instead of leaving the dogs to their own things, we opted for artificial insemination. And the outcome was remarkable—the female dog became pregnant and gave birth to a healthy litter of 10 puppies.

This story highlights the importance of professional involvement, not only for the technical aspects such as timing and medical oversight but also for managing the breeding event itself.

Observing and confirming copulation can make all the difference between a missed opportunity and a successful conception.

Use of Reproductive Technologies

Artificial insemination (AI) is a powerful tool in the field of canine reproduction. It was primarily devised to enable breeding when natural mating isn’t feasible due to behavioural issues, physical incompatibilities, geographical distance, or any other barriers one could encounter really. And it becomes particularly useful when we look into more advanced methods such as intra-uterine insemination for instance.

Intra-uterine insemination involves depositing sperm directly into the uterus. This is significantly more effective than depositing sperm into the vagina, which is what occurs during natural mating. One advanced method of intra-uterine insemination is transcervical insemination (TCI), which is performed using an endoscope—a medical device that allows a veterinarian to see inside the vagina and perform procedures without invasive surgery. During TCI, the endoscope is used to guide a catheter through the cervix to deposit sperm directly into the uterus, effectively bypassing the cervical barrier, which under normal circumstances would filter out many of the sperm cells.

This technique is particularly valuable when using frozen semen, which may have reduced motility and lower numbers compared to fresh semen. By placing the sperm closer to the eggs, the chances of fertilization are increased. Additionally, in cases where the male has subpar semen quality or the female has a history of infertility, TCI can significantly enhance the chances of a successful pregnancy and potentially increase litter size by maximizing the number of sperm cells that reach the eggs. Something to keep in mind here!

Regarding hormonal treatments, it is important to know that we do have protocols that can induce estrus (the period in which a female is receptive to mating) in female dogs. And I am often asked if using these techniques can induce a superovulation—the release of a greater than normal number of eggs during ovulation—in canines actually. I don’t think so honestly…

In other species, superovulation is a technique often used in conjunction with AI to increase the number of offspring produced. However, because dogs naturally ovulate multiple eggs, it’s challenging to determine if hormonal treatments truly lead to superovulation. On top of that, we often use those protocols on animals with a history of fertility issues… so it is hard to know for sure if by doing so we truly increase their ovulation capacity.

What is the average dog litter size by breed?

When discussing average litter sizes, the spectrum is as varied as the dog breeds themselves. Breed size plays a considerable role, often giving us a preliminary guide on what to expect when a litter is due.

The great thing is: science actually gives us some pointers on what to expect here!

A study performed in Norway actually gave us numbers on the average litter size one can expect in 224 dog breeds… which is a real treasure for one who wants to assess what to expect in their specific breed.

The paper actually only shares these figures for the Top 100 breeds (still a great start in my opinion though), and those should be considered as starting guidelines in my opinion. As I’ve previously highlighted, myriad factors indeed impact dog litter size. Still, possessing this knowledge certainly provides an excellent foundation for anyone involved in dog breeding.

Large litters of puppies can increase the risk of perinatal and neonatal mortality

And moreover, as you scrutinize the data table I’ve provided below, you might stumble upon some truly… fascinating revelations!

Take, for example, the Cavalier King Charles spaniel. It was astonishing to discover that there was a record of a litter size reaching 15 for this breed! Considering the average litter size for Cavalier King Charles is typically around 4, a 15-puppy litter is, honestly, quite remarkable. It’s almost record-setting for such a small breed. This is not something I’ve never come across in my years of experience, but it’s an eye-opener that such a large litter in this breed is indeed possible.

The breed topping the charts with the most prolific dog litter size is… the Rhodesian Ridgeback. Their reputation for large litters didn’t come as a surprise to me. This is a topic I often discussed with my mentor at the veterinary school in Paris. He often remarked on how females of this breed were known to have very large litters, and I can attest to their remarkable fertility, as I’ve yet to see a Ridgeback fail to conceive, even when inseminated with semen of lesser quality. The findings of this study provide solid confirmation of this fact here!

Conversely, the Pomeranian and Toy Poodle breeds are on the opposite end of the dog litter size spectrum. They average a litter size of merely 2.4 puppies. This isn’t unexpected, as miniature breeds are naturally inclined to have smaller litters. This fact however underscores the criticality of precise ovulation timing for these breeds, particularly if the goal is to maximize dog litter size – which comes as a natural priority when we think of it in terms of genetic selection.

FYI – the world record (yes, there is one!) for the largest litter size in dogs is held by a Neapolitan Mastiff named Tia, who gave birth to 24 puppies on November 29, 2004. This event took place in the UK, and the litter was delivered by Cesarean section. This record-breaking event is listed in the Guinness World Records.

BREED	AVERAGE LITTER SIZE	RANGE
Alaskan Malamute	6.9±0.3	2-11
American Cocker Spaniel	5.3±0.2	1-10
Australian Terrier	5.5±0.4	1-8
Basenji	4.8±0.4	1-8
Basset Hound	6.7±0.8	1-11
Beagle	5.5±0.2	1-10
Belgian Shepherd Dog (Groenendael)	6.3±0.4	2-11
Belgian Shepherd Dog (Tervueren)	6.2±0.4	1-11
Bernese Mountain Dog	6.4±0.3	1-15
Bichon Frisé	4.6±0.1	1-10
Bichon Havanais	4.3±0.2	1-9
Border Collie	6±0.1	1-16
Border Terrier	5.1±0.4	1-9
Boston Terrier	4.1±0.3	1-8
Boxer	6.6±0.2	2-12
Brittany Spaniel	6.4±0.3	1-10
Bull Terrier	5.5±0.4	1-9
Cairn Terrier	4.4±0.1	1-8
Cavalier King Charles	4.1±0.1	1-15
Chihuahua	3.2±0.1	1-7
Chinese Crested	4.3±0.2	1-9
Chow Chow	4.4±0.4	1-10
Cocker Spaniel	5.7±0.2	1-14
Collie (Rough)	5.2±0.2	1-10
Coton de Tuléar	3.8±0.3	1-8
Dachshund	5.4±0.1	1-13
Dachshund (Miniature)	4.4±0.1	1-8
Dachshund (Rabbit)	3.3±0.2	1-6
Dalmatian	8.4±0.5	1-15
Danish-Swedish Farmdog	4.2±0.3	1-8
Dobermann	7±0.4	1-13
Dogue de Bordeaux	8.1±0.8	2-17
English Bulldog	5.4±0.4	1-10
English Setter	6.4±0.1	1-13
English Springer Spaniel	7.3±0.3	1-13
Eurasier	6.7±0.6	1-13
Finnish Hound	7.1±0.3	1-13
Finnish Lapphund	5.2±0.3	2-9
Finnish Spitz	3.7±0.2	2-6
Flat Coated Retriever	8.3±0.3	1-15
French Bulldog	4.7±0.3	1-8
German Shepherd Dog	6.1±0.1	1-14
German Shorthaired Pointer	8.3±0.4	1-15
German Wirehaired Pointer	7.3±0.4	1-14
Giant Schnauzer	7±0.5	1-14
Golden Retriever	7.5±0.2	1-14
Gordon Setter	7.6±0.2	1-16
Great Dane	7.1±0.6	1-13
Greenland Dog	5.6±0.4	1-10
Hamilton Hound	6.5±0.5	3-11
Icelandic Sheepdog	4.5±0.3	2-6
Irish Setter	7.1±0.2	1-13
Irish Soft Coated Wheaten Terrier	5.8±0.2	1-10
Italian Greyhound	3.3±0.3	1-6
Jack Russell Terrier	4.4±0.1	1-10
Japanese Spitz	3.9±0.1	1-7
Labrador Retriever	6.9±0.2	1-13
Lagotto Romagnolo	6.7±0.3	4-12
Leonberger	8.4±0.5	1-15
Lhasa Apso	4.9±0.3	1-9
Manchester Terrier	4.7±0.3	2-7
Miniature Pinscher	4.3±0.1	1-7
Miniature Schnauzer	4.7±0.1	1-10
Newfoundland	6.5±0.4	1-12
Norfolk Terrier	2.5±0.2	1-6
Norwegian Buhund	4.9±0.3	1-8
Norwegian Elkhound Black	5.2±0.3	1-11
Norwegian Elkhound Grey	5.5±0.1	1-12
Norwegian Hound	7.4±0.6	1-17
Norwegian Lundehund	3.2±0.2	1-5
Nova Scotia Duck Tolling Retriever	6.6±0.2	2-12
Papillon	3.3±0.1	1-7
Petit Basset Griffon Vendéen	5.1±0.4	1-10
Phalène	3.3±0.2	1-6
Pointer	7.2±0.3	1-12
Pomeranian	2.4±0.1	1-6
Poodle (Medium)	3.7±0.2	1-10
Poodle (Miniature)	3.0±0.1	1-8
Poodle (Standard)	7±0.2	2-12
Poodle (Toy)	2.4±0.1	1-4
Pug	4.2±0.2	1-8
Rhodesian Ridgeback	8.9±0.6	1-15
Rottweiler	7.4±0.2	1-14
Samoyed	6.2±0.4	1-12
Schnauzer	7±0.4	2-11
Shetland Sheepdog	3.9±0.1	1-8
Shiba Inu	3.3±0.3	1-7
Shih Tzu	4.2±0.2	1-9
Siberian Husky	5.1±0.2	1-14
Small Munsterlander	6.9±0.2	1-13
St Bernard	6.8±0.5	1-18
Staffordshire Bull Terrier	5.6±0.2	1-12
Swedish Dachsbracke	6.1±0.3	1-12
Swedish Elkhound	7.5±0.3	1-14
Tibetan Spaniel	3.8±0.3	1-8
Tibetan Terrier	5.2±0.3	1-9
Welsh Corgi (Pembroke)	5.5±0.4	1-9
West Highland White Terrier	3.7±0.3	1-8
Whippet	6.1±0.3	1-10
Yorkshire Terrier	3.5±0.3	1-6

Average litter size in 100 dog breeds, adapted from Borge et al, 2010

How Many Times Can a Dog Safely Give Birth?

For those involved in breeding, there’s a critical statistic to remember concerning dog breeding: approximately 15% of canine births are affected by dystocia.

Dystocia refers to difficult labor or delivery, which can manifest as a potentially dangerous situation for both the mother and her puppies. While this condition is more prevalent in certain breeds, particularly brachycephalic dogs with their distinctive flat faces, it’s a risk that any breed can face truthfully.

Predicting dystocia is challenging, often leading to considerable worry for dog breeders. Consequently, monitoring each dog litter during whelping is essential.

Everything You Need to Know Re: Whelping in Canines

Dog Litter Size and Dystocia

It is well-described in the veterinary scientific literature: litter size can impact the outcome of whelping in female dogs.

Singleton litters for instance often lead to something we refer to as the “single puppy syndrome“. When it comes to the birthing process, numerous hormonal mechanisms activate to resume uterine contractions, allowing the puppies to be expelled. This cascade is often triggered by the puppies themselves, who send a hormonal signal to kickstart the whelping process. Yet, with small litters, or when there’s a singleton puppy, particularly in large breeds, this signal may not be potent enough, leading to a lack of natural labor initiation. Consequently, veterinarians frequently suggest scheduling an elective C-section for females expecting only a single pup.

And the same can happen… when dealing with very large litters actually! A high number of puppies can lead to primary or secondary uterine inertia (FYI – uterine inertia is a condition in which the uterus is unable to contract effectively during labor, which can result in prolonged or difficult delivery). This happens because the uterus is overstretched, resulting in weak contractions or prolonged labor that put both the mother and the puppies at risk.

👉🏽Activity monitors during gestation are game-changers, enabling us to detect the onset of labor and identify potential complications during pregnancy. In this critical period, there’s no doubt that an ounce of prevention is worth a pound of cure.

My personal favorite? This one right here. The reason I am super excited about it is because they validated a Pregnancy Health Monitor that is in my opinion game-changing. Use code TMV_CARE for a 10% discount.

Long term consequences

It’s also important to acknowledge the risks associated with multiple litters. Each time a bitch delivers a litter, the process of the placenta detaching from the uterus can cause microlesions. Over time, these may contribute to subtle, yet significant, reproductive issues, such as subclinical endometritis, which may affect future litter size and fertility.

The general guideline I’ve stood by is that a female dog should ideally be limited to producing no more than 4 litters in her lifetime. However, this isn’t a hard and fast rule. Biology isn’t exact, and individual circumstances may lead to adjustments in this number.

The key criterion is ensuring the dam’s optimal health before breeding. A reproductive veterinarian’s assessment, through a breeding soundness evaluation, is the most reliable method to ensure a dog is fit for breeding and can safely carry a litter.

When considering Cesarean sections, my personal stance is to cap the procedure at 3 per dog. With each surgery, the risk of internal adhesions increases, which can lead to complications. Therefore, limiting the number of C-sections can help to minimize potential risks, though, as with all guidelines, this is not inflexible. It’s a decision to be made in consultation with a professional veterinary surgeon.

Ultimately, the paramount concern is safeguarding the well-being of the female dog – and as we said earlier, this is something that will impact dog litter size for sure. The health of the mother is the cornerstone of responsible breeding practices and must always take precedence.

Dog Litter Size: How Many Puppies Typically Thrive?

As I mentioned in an earlier blog, the puppy survival rate is a critical measure in dog breeding. And this could actually be influenced… by the size of the litter!

The impact of dog litter size on neonatal survival is an aspect breeders must consider with utmost seriousness. Indeed, there’s a direct correlation between dog litter size and the weight of the puppies at the time of their birth: typically, the larger the litter, the smaller each puppy tends to be. And these smaller puppies… face a higher risk of neonatal mortality!

a litter of Labrador puppies, representing the impact dog litter size can actually have on neonatal health and what measures dog breeders must take to optimize newborn puppy care

Research within canine reproductive health has demonstrated that when confronted with a larger dog litter size, there could be an expectation that up to 30% of the puppies will be born underweight.

In defining what constitutes a “large” dog litter size, the breed’s size is a determining factor.

For small breed females under 10kg (22 lbs), more than 5 puppies is considered a large dog litter size.
In medium breed females, those weighing between 15-25kg (33-55 lbs), a dog litter size of 6-9 puppies categorizes as large.
And for the larger breeds, females weighing over 25kg (over 55 lbs), any dog litter size above 9 is deemed large.

These parameters serve as a basic framework, but I also recommend referencing the comprehensive breed-specific table provided earlier for a more nuanced understanding.

And actually, there are two essential actions to take from this information:

First, determining the expected dog litter size in advance of the birth is invaluable. An X-Ray after the 45th day of gestation, which is the point when the puppies’ skeletons are sufficiently calcified, can reveal the precise count of the expected litter. I typically prefer to perform this exam at 50 days into the gestation, as I find the pictures easier to interpret at this stage. Just so you know, puppy counting has become a common guessing game on numerous social media forums, so if any doubt, just know that you have an army of “puppy counters” out there ready to help you out thanks to their Photoshop skills!

Interested to learn more about canine neonatology? Download my free ebook on the topic

The second action is equally crucial: if a large dog litter size is anticipated, breeders should proactively tailor their newborn puppy care protocols to address this. By adjusting care strategies beforehand, breeders can be better prepared to nurture and increase the survival chances of those puppies born with a lower birth weight—potentially the 30% of the litter that falls into this vulnerable category as we just mentioned!

With focused attention and preparedness, breeders can foster a nurturing environment that supports every puppy, giving each one the best possible start in life.

👉🏽 It is crucial to weigh newborn puppies at birth and daily throughout the neonatal period (from birth to 3-4 weeks of age), as consistent weight monitoring is a key indicator of their health and development. I recommend starting with kitchen scales (like this one), but for serious accuracy, consider this lab-grade scale, perfect for tracking puppy weights up to 5kg.

FAQ: Common Questions About Dog Litter Sizes Answered

How Can Breeders Influence Dog Litter Size?

Breeders have a hand in influencing dog litter size through mindful attention to the following elements:

Breeding age: Ideal breeding age plays a significant role in litter outcomes, with too young or old dams often producing smaller litters.
Genetics: as mentioned earlier, there is definitely a line effect, with certain lines in any given breeds being more prolific than other; on top of that, optimizing each breeding for genetic diversity will definitely help optimize litter size as well.
Breeding management:
- Breeding soundness evaluation: remember, only breed healthy females; the healthier they are, the better fertility results. This can be evaluated by evaluated by a repro vet prior to breeding
- Selection of the male: semen quality is an important parameter, as discussed earlier it impacts fertility AND potentially, litter size as well. Make sure a recent spermogram has been performed on the male so you know what to expect there.
- Timing of ovulation: this is definitely the key element to bring everything together. Remember, mistiming of the time of breeding is the number one cause of infertility in canines. And here, progesterone tests remain THE gold standard.

What Are the Signs of a Large Litter?

Predicting a large litter size can often be gauged by observable signs in the dam. A significant increase in abdomen size may indicate a higher-than-average litter size, although this should be confirmed by a veterinarian through X-ray to determine an accurate puppy count.

Beware, ultrasounds CANNOT give you an exact number, it is always an estimation we get there.

I’m preparing for my bitch to have a large litter. Are there specific measures I should implement?

Yes, there are indeed specific measures you should implement when preparing for your bitch to have a large litter.

Here’s a focused approach to ensure the health and vitality of the mother and her puppies:

– Nutrition: It’s crucial to provide proper nutrition throughout the gestation period. I’ve outlined recommendations previously on this page that can guide you through this. Adequate nutrition is pivotal in not just supporting the mother’s health but also in optimizing the vitality of the newborns. Given that up to 30% of newborn puppies could be at risk of low birth weight in larger litters, the right dietary regimen is essential.

– Food Intake: Ensure that your dog maintains a steady food intake, especially during the final third of gestation. It’s a critical period, as some dogs—particularly smaller breeds—may become finicky with their food, or struggle to eat due to the pressure of the enlarged uterus on the stomach. Transitioning to a growth diet, like a puppy food, can make a significant difference. These diets are dense in essential nutrients and are designed to support gestation even when consumed in smaller volumes. For those that are particularly choosy or have a reduced appetite, incorporating wet food can be beneficial. If a dog stops eating entirely, there’s a risk of developing pregnancy toxemia—a serious condition that is best prevented.

– Parturition Management: Brush up on your knowledge of managing canine parturition, particularly as it pertains to larger litters. It can be an exhausting process for the mother to deliver numerous puppies, and she will need your support. Be prepared to intervene and provide assistance where necessary, ensuring that you’re familiar with the proper protocols for such situations.

– Newborn Puppy Care: Start fine-tuning your protocols for newborn puppy care immediately. With larger litters, there’s a heightened chance you’ll have puppies with low birth weight that will require extra attention. The care provided in these first critical moments can greatly influence their survival and long-term health.

Implementing these measures will put you in the best position to manage a large litter successfully and ensure the well-being of both the mother and her puppies.

👉🏽 Here is the colostrum replacer I recommend for newborn puppies (where available). It’s especially beneficial for premature puppies, low birth weight puppies, and those born to females undergoing an elective C-section.

It is also available through a breeder program. Learn more about options in the USA and Canada.

👉🏽Neonatal growth charts are an excellent tool to quickly identify puppies with low birth weight, helping breeders and veterinarians take early action. These charts include data from over 115 different puppy breeds. Download them here!

👉🏽It is crucial to weigh newborn puppies at birth and daily throughout the neonatal period (from birth to 3-4 weeks of age), as consistent weight monitoring is a key indicator of their health and development. I recommend starting with kitchen scales (like this one), but for serious accuracy, consider this lab-grade scale, perfect for tracking puppy weights up to 5kg.

👉🏽 To ensure accurate temperature monitoring, I recommend using a pediatric digital thermometer like this one or an infrared thermometer like this one for a non-invasive option. Both are fast, reliable, and essential for tracking a newborn puppy’s health.

👉🏽Maintaining the ideal temperature for newborn puppies is crucial for their survival and well-being. There are different options available, including a heating lamp for evenly distributed warmth (like this one), a heating pad with adjustable settings for targeted heat (like this one), or a pediatric incubator, which offers precise temperature and humidity control (like this one). Choosing the right option depends on your needs, but each plays a vital role in keeping your puppies warm and healthy.

In light of the many factors that can impact litter size in dogs – breed, age, and breeding method – it is imperative that breeders and veterinarians work in tandem to ensure the well-being of both mothers and their offspring. With a thorough understanding of these elements and the proper measures in place, the breeding process can yield successful, healthy litters. By recognizing the potential consequences of litter size on maternal health and taking the necessary precautions, breeders and veterinarians can strive for the best possible outcomes for all involved.