Birth Weights, Growth Patterns, and the Early Warning Signs We Shouldn’t Ignore

There are few pieces of equipment in a whelping room quite as unremarkable as a digital kitchen scale. It doesn’t have the sophistication of an ultrasound machine or the apparent importance of the emergency supplies we’ve carefully assembled before a litter arrives.

Yet it may be one of the most valuable tools we own.

Most breeders weigh their puppies at birth. We record the numbers, compare littermates, and perhaps make a mental note of the smallest and largest puppies. We may even find ourselves feeling particularly pleased when everyone appears to be gaining nicely.

But what happens when they aren’t?

What does a small loss mean? How much variation should we expect between littermates? And perhaps most importantly, are we simply collecting numbers, or are we learning to recognize what those numbers are telling us?

These questions are at the heart of some particularly interesting research into canine neonatal survival, and they are subjects reproductive veterinarian Dr. Emmanuel Fontaine has been encouraging breeders to consider more carefully.

His message is straightforward: a scale can help us recognize trouble before a puppy looks ill.

The science behind that observation deserves our attention.

Birth Weight Is More Than a Number

A puppy’s birth weight reflects, in part, how successfully it developed before delivery.

Within any litter, we naturally expect some variation. Even puppies sharing the same mother, uterus, and pregnancy may arrive at noticeably different sizes.

That variation alone doesn’t tell us everything about their health, but research has repeatedly identified low birth weight as an important risk factor for neonatal mortality.

Smaller newborns may have fewer energy reserves, greater difficulty maintaining body temperature, and less ability to compete with their larger littermates for nursing opportunities.

For breeds such as the Staffordshire Bull Terrier, where we may have relatively small litters and considerable familiarity with the size and development of puppies within our own breeding programs, those observations can be particularly useful.

But familiarity has its limitations.

A puppy that seems small compared with its siblings may fall within an expected range for its breed, while another that appears perfectly average may still be at risk.

This is why researchers increasingly emphasize evaluating birth weights in relation to breed-specific information rather than applying one universal standard to every newborn dog.

A Chihuahua and a Great Dane clearly cannot be evaluated using identical birth-weight expectations. Even among breeds of similar adult size, normal neonatal patterns may differ.

Birth weight provides our starting point.

What happens afterward tells us considerably more.

The First 48 Hours: A Window Worth Watching

In our earlier article about colostrum, we discussed how important the first hours after birth are for establishing passive immunity.

Those same hours provide valuable information about a puppy’s ability to feed successfully.

A newborn that nurses effectively should receive the energy and hydration necessary to begin establishing a healthy growth pattern.

But simply observing a puppy attached to a teat does not guarantee adequate milk intake.

This is where the scale becomes particularly useful.

Research published by Mila and colleagues in 2015 examined the relationship between birth weight, early growth, and neonatal mortality. Their findings identified both low birth weight and poor growth during the first two days as important risk factors.

Subsequent research has reinforced the value of monitoring weight changes during this period.

One finding is especially worth remembering: puppies that lose approximately 4% or more of their birth weight during the first 48 hours have been identified as having an increased risk of neonatal mortality.

That doesn’t mean every puppy reaching that threshold will become ill, nor does it mean a puppy losing less than 4% is necessarily safe.

It means the pattern deserves investigation.

There is a distinction between recognizing a risk factor and treating it as a diagnosis.

A scale cannot tell us why a puppy is losing weight. It can, however, tell us that something may not be progressing as expected.

And that information may become available before the puppy begins showing obvious signs of distress.

But Isn’t Some Weight Loss Normal?

This is where experience and emerging research sometimes challenge one another.

Many of us have been taught that a certain amount of weight loss immediately after birth is acceptable.

And indeed, studies have documented puppies that experience some early weight loss and subsequently develop normally.

However, we should be cautious about using that observation to justify automatically dismissing early losses.

Dr. Fontaine has been particularly direct in challenging the assumption that newborn puppies can safely lose a substantial percentage of their birth weight simply because they have just been born.

I think his point is worth considering.

Something can occur relatively frequently without necessarily being desirable.

When weight loss appears, particularly during those first two days, we should be asking whether the puppy is nursing effectively, maintaining appropriate body temperature, and behaving normally.

We should also be paying attention to whether the weight is stabilizing, improving, or continuing to decline.

The mistake is not necessarily in observing a modest early loss.

The mistake is deciding that it requires no attention simply because we’ve seen it before.

Trends Tell Us More Than Individual Measurements

One of the most important lessons in neonatal monitoring is that a single weight is only a snapshot.

A puppy’s growth pattern provides the broader picture.

Consider two puppies that happen to weigh exactly the same on their third day of life.

One began considerably smaller and has gained steadily since birth. The other began larger, lost weight, and has only recently returned to its birth weight.

Those two puppies have arrived at the same number by very different routes.

Their growth patterns tell different stories.

This is why I prefer the idea of tracking individual progress rather than simply comparing puppies to one another.

An unusually small puppy that gains consistently may be progressing more satisfactorily than a larger littermate whose growth has slowed or stopped.

The scale allows us to recognize that distinction.

Research into early canine growth has also produced mathematical models and growth charts designed to show expected developmental patterns.

These tools can help breeders and veterinarians recognize when an individual puppy begins deviating from its expected trajectory.

But even without sophisticated software, a carefully maintained record can tell us a tremendous amount.

Birth weight, early measurements, daily progress, and notes about nursing behavior create a useful history for each puppy.

And in the event of a problem, that history can be enormously valuable.

Growth Charts: Looking Beyond the Average

An interesting development in canine neonatal research is the increasing use of growth curves and percentile charts.

Rather than simply asking whether a puppy is gaining weight, these charts help us consider whether it is growing along an expected trajectory.

Dr. Fontaine discusses this concept in his article How Can a Simple Scale Prevent Puppy and Kitten Neonatal Loss?

A puppy that consistently follows its established growth curve is generally more reassuring than one whose measurements begin to fall across successive percentile lines.

A marked downward shift can signal that growth is becoming inadequate, even if the puppy continues to gain a small amount of weight.

Conversely, unusually rapid changes may also deserve closer attention.

However, growth charts are only as useful as the reference population behind them. A chart developed for another breed or age range may not accurately reflect what we should expect from a Stafford puppy.

I would rather use a well-maintained individual record than create false confidence by comparing puppies against an inappropriate chart.

Where breed-specific neonatal references are available and properly validated, they may provide an additional tool.

Where they aren’t, consistent monitoring remains valuable.

The goal is not to turn breeding into a mathematical exercise. It is to use available information to support better judgment.

Making Weighing Part of the Daily Routine

One of the advantages of neonatal weighing is that it requires very little equipment.

A reliable digital scale capable of measuring in grams, a small container or basket, and a written record are generally all that is necessary.

Consistency matters.

Weighing at approximately the same time each day, preferably under similar conditions, makes the results easier to interpret.

Because newborn puppies may have recently nursed or eliminated, small fluctuations should be considered in context.

During the earliest hours, additional measurements can be particularly useful.

Recording birth weight, checking again at approximately 12 and 24 hours, and including a 48-hour measurement establishes a valuable early picture.

Afterward, daily weighing throughout the neonatal period allows us to follow each puppy’s progress.

Individual identification is equally important. The numbers are only useful if we can confidently associate each measurement with the correct puppy.

This may seem obvious, but anyone who has raised a litter of similarly marked puppies understands how easily confusion can occur.

Simple systems are often the most dependable.

When the Numbers Tell Us to Look Closer

A scale cannot diagnose hypoglycemia, dehydration, infection, or inadequate passive immune transfer.

It cannot tell us whether a puppy has a congenital problem or whether the dam’s milk production is sufficient.

But it can alert us to changes that deserve investigation.

A puppy that fails to gain weight as expected may be nursing inadequately, struggling to maintain body temperature, or developing an underlying illness.

Continued weight loss, particularly when accompanied by weakness, poor nursing, persistent crying, unusual quietness, or changes in activity, should never be dismissed.

These are situations in which veterinary consultation becomes important.

For a puppy that is weak, cold, unable to nurse, or showing respiratory difficulties, prompt veterinary assessment is necessary regardless of what the scale says.

And while supplementary feeding may sometimes be appropriate, it should not become an automatic response to every disappointing number.

A chilled puppy, for example, may not be able to digest milk normally. Improper bottle or tube feeding can cause aspiration and serious complications.

Our first responsibility is to understand what may be happening, not simply to make the number increase.

The scale is an early warning system.

It is not a treatment plan.

Why These Records Matter Beyond the Whelping Box

There is another benefit to careful neonatal recordkeeping that deserves consideration.

Over time, records from multiple litters can help us recognize patterns within our own breeding programs.

We may begin to see relationships between birth weights, litter size, delivery circumstances, maternal behavior, and early growth.

Perhaps certain puppies consistently require more attention during the first few days. Perhaps a particular dam has excellent maternal instincts but needs additional monitoring of milk production. Perhaps difficult deliveries are associated with slower early progress.

These observations are not automatically proof of cause and effect.

However, they give us information worth discussing with our veterinarians and considering when planning future litters.

Responsible breeding has always involved observing, evaluating, and learning from the generations we produce.

Good records make that process more meaningful.

They also provide valuable information when a veterinarian needs to evaluate a struggling newborn.

Instead of relying on recollection, we can provide a clear timeline of measurable changes.

Sometimes that is exactly what helps identify a problem before it becomes much more difficult to manage.

The Difference Between Watching and Understanding

There is an old tendency in animal husbandry to place considerable confidence in a practiced eye.

And there is good reason for that.

Experience teaches us things that cannot always be captured in a chart. We recognize familiar behaviors, subtle changes in nursing, differences in temperament, and signs that something simply isn’t quite right.

I would never dismiss that knowledge.

But experience becomes even more valuable when we support it with objective information.

A breeder may recognize that a puppy appears less vigorous than its littermates. A scale may reveal that the same puppy has been gaining progressively less weight over several days.

Neither observation should replace the other.

Together, they provide a clearer picture.

This is one reason I appreciate the work of veterinarians such as Dr. Fontaine, who continue to bring scientific research into practical conversations with breeders.

They remind us that improving our methods does not require abandoning our experience.

It requires being willing to strengthen it.

The best breeders I know have never stopped learning. They may have decades of experience, but they remain interested in new research, better equipment, and more effective ways to care for the animals entrusted to them.

That curiosity is not a sign that we lack knowledge.

It is recognition that there is always more to understand.

And sometimes, something as ordinary as a kitchen scale can teach us a great deal.

Because the numbers themselves are only part of the story. What matters is whether we are paying attention to what they are telling us.

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Further Reading and Scientific References

Dr. Emmanuel Fontaine, DVM

How Can a Simple Scale Prevent Puppy and Kitten Neonatal Loss? (2026)

How Can a Simple Scale Prevent Puppy and Kitten Neonatal Loss?

Newborn Puppy Colostrum: Daily Weighing Beats Picking the Best Teat

Newborn Puppy Colostrum: Daily Weighing Beats Picking the Best Teat

Scientific Research

Mila, H., Grellet, A., Feugier, A., & Chastant-Maillard, S. (2015). Differential Impact of Birth Weight and Early Growth on Neonatal Mortality in Puppies. Journal of Animal Science.

https://pubmed.ncbi.nlm.nih.gov/26440343

Relative Impact of Birth Weight and Early Growth on Neonatal Mortality in Puppies (2023).

https://pmc.ncbi.nlm.nih.gov/articles/PMC10295787

A Model of Puppy Growth During the First Three Weeks (2020).

https://pmc.ncbi.nlm.nih.gov/articles/PMC7738731

Evaluation of Canine Neonatal Health by Breeders (2023).

https://pmc.ncbi.nlm.nih.gov/articles/PMC10705106

This article is intended for breeder education and does not replace veterinary examination, diagnosis, or individualized neonatal care. Puppies showing signs of illness or compromised feeding require prompt professional assessment.

Educational series presented by The Stafford Knot, Inc., a 501(c)(3) nonprofit organization, in collaboration with Wavemaker Staffords.