I've been breeding dogs for over fifty years, boxers, working breeds, and everything in between. In that time, I've had a lot of 2 a.m. phone calls. The ones that stay with me are the ones where a new breeder is standing in their whelping room, voice shaking, telling me that their mother dog is pacing the box, won't let the puppies nurse, and just snapped at a newborn. "She's never been aggressive a day in her life," they say. "I don't know what's wrong with her."

I know what's wrong with her. Most of the time, it's calcium.

This article is the short version of everything I want new breeders to know before that call happens to them. For the full science, dosing tables, sourcing, the complete staging guide, I'll point you to our detailed resource at the end. But right now, let's talk about what you actually need to understand.

This isn't a bad dog. This is a sick dog.

The behaviors we call "bad mothering"--pacing, aggression toward puppies, excessive digging, restlessness, rejecting or attacking newborns--are often not behavioral problems at all. They are neurological symptoms of low blood calcium, also known as "hypocalcemia".

Calcium isn't just about bones. Your dog's nervous system runs on it. When blood calcium drops too low, the brain does not function correctly. Nerve signals misfire. Muscle control suffers. Anxiety and hyperreactivity spike. The dog is not being a bad mother. Her brain is in a medical emergency. The medical term for it is eclampsia, and it can take on a variety of symptoms before it becomes life-threatening to the mom.

I sometimes explain it this way: there was a time in human history when people were institutionalized for erratic, violent, or unpredictable behavior. We now know that low calcium  in humans can directly influence behavior, mood, and cognitive function, with symptoms ranging from irritability and anxiety to confusion and, in severe cases, seizures. Some human patients improve behaviorally when calcium and Vitamin D levels are normalized. We didn't understand the connection then, and I often wonder if those people sent to "mental institutions" might have benefitted from this normalization of calcium. Breeders make the same mistake with their dogs every day, they see the behavior and judge the dog, when what they should be seeing is a medical crisis they can help fix.

What Is Eclampsia?

Eclampsia - also called "puerperal tetany" or "periparturient hypocalcemia" - is a severe condition caused by dangerously low calcium levels in the bloodstream. It most often affects small-breed dogs with large litters during peak lactation (2 to 3 weeks after whelping), but it can happen in any breed at any time during lactation; and sometimes even during whelping. "Tetany" means prolonged involuntary muscle contractions/spasms."Hypocalcemia" means low blood levels of calcium. 

Veterinary medicine typically diagnoses eclampsia using a blood test to measure calcium levels. There are two tests they might offer; a blood serum test, and an ionized calcium test. A blood serum calcium level below about 7.5 mg/dL (normal being 9.0–11.5 mg/dL), or an ionized calcium level below 1 mmol/L (normal being ˜1.12–1.40 mmol/L) is reason for treatment with IV calcium by a veterinarian, though different labs may have different measurements or acceptable ranges.

Why It Happens

This occurs due to physiological changes in mineral metabolism during the transition from pregnancy to lactation. In plain language, it is due to excessive calcium loss into milk combined with inadequate dietary calcium intake.

• Heavy calcium demand for milk production depletes the mother’s calcium stores.
• Calcium supplements during pregnancy can increase risk by suppressing natural calcium regulation.
• Poor diet during pregnancy or lactation also contributes.

The risk nobody talks about: Infanticide.

In severe cases, especially when a dam has had a C-section and is already neurologically compromised from low calcium, she may not recognize her puppies as her own. The aggression can escalate to the point where she injures or kills them.

I received a video this year from a breeder whose dam had just had a C-section with five adorable little Boston puppies. From the footage, I could already see the signs of early eclampsia, the frantic quality to her movements, the look in her eyes. She was treating the babies as if they were toys or prey. She was not mothering or nursing them. I told them what I was seeing. They stepped out of the room for a few minutes. They came back to find all the puppies dead. I had a serious cry over that one, and decided to write this article, determined to get the word out that infanticide is real. I've taken way too many calls in the last year like this, and we all need to share this information. As hard as infanticide is to consider, knowledge is power.

This happens. It is not rare. And in almost every case I've seen, it was preventable, because what looked like aggression was calcium deficiency, and calcium was available.

If your dam has had a C-section, or if she is showing any of the early signs below, do not leave her unsupervised with newborns. Remove the puppies, get them on milk replacer, and get calcium into her first.

Supervise. Supervise. Supervise.

The one rule you cannot break.

Do not give calcium supplements during pregnancy. Start at the onset of active labor. Continue through the entire nursing period, until the last puppy is weaned, especially if you have observed any eclampsia symptoms.

This sounds counterintuitive, shouldn't a pregnant dog have extra calcium? No. During pregnancy, her body learns to regulate its own calcium supply. If you supplement during that time, her regulatory system goes quiet because it doesn't need to work. Then lactation hits and calcium demand rises sharply, and her body can't keep up because you've been doing the work for it instead. That crash is eclampsia, and it is a true medical emergency. It can also result in uterine inertia during whelping. 

The rule is: Nothing during pregnancy. Everything during nursing.

Why some vets miss early eclampsia.

Even when the signs are right in front of them.

One thing I want every breeder to understand is this: a dam can be in early or mid-stage eclampsia even when her blood calcium looks "normal." This is where a lot of well-meaning veterinarians get tripped up. They run a quick total calcium test, see a number in the normal range, and conclude that calcium isn't the problem. Meanwhile, the dam is pacing, glassy-eyed, trembling, rejecting her puppies, or coming out of a C-section acting "off" in a way that every experienced breeder recognizes instantly.

Here's the truth: total serum calcium can stay normal until the crisis is advanced. The body will do everything it can to keep blood calcium stable because the heart and diaphragm depend on it. A dog can be neurologically crashing while her total calcium still looks fine on paper. What actually drops first is ionized calcium, the biologically active form, and many ER clinics don't run that test unless they're specifically looking for it. If you aren't sure which screen they are running for calcium, ask. You want ionized calcium, and you want treatment based on symptoms.

The Merck Veterinary Manual itself makes this same point, noting that the severity of clinical signs may not correlate with total calcium concentration, since ionized calcium is affected by protein binding and acid-base status in ways total calcium isn't. Clinical signs matter more than a normal lab value in the early stages.

Know these signs. Right now. Before you need them.

Some early signs overlap with completely normal nesting behavior: restlessness, pacing, panting, not settling. On their own, before active labor has actually started, these are usually just nesting behaviors, not a reason to give calcium yet. Eclampsia is more often reported after the whelping is completed, but it can occasionally turn violent towards puppies even during active whelping. Low calcium levels during whelping can also contribute to uterine inertia, a subject for another article.

The signs that mean something more specific: a stiff or "wooden" walk, aggression or snapping, twitching, or unusual startling at ordinary sounds. These aren't things ordinary nesting causes. If you see these, especially in combination, treat it as an early warning sign regardless of whether active labor has technically started, A real hypocalcemic crisis doesn't wait for the "right" stage to become dangerous.

Eclampsia most often occurs after whelping is finished, and it can move fast. Early, mild eclampsia can become life-threatening within an hour or two. Study these signs now, while you're calm, so you recognize them at 3 a.m. when you're tired.

Mild Eclampsia, Act Now (she can still be helped at home)

• Restlessness, pacing, won't settle
• Panting when she shouldn't be
• Stiff, "wooden" walk, not limping, just oddly rigid
• Refusing food when she was eating fine
• Startling at normal sounds
• Staring at puppies with strange intensity, nosing them obsessively, trying to move them without purpose
• Staying out of the box more than she should
• Refusing to settle to nurse puppies
• Aggression or snapping at puppies
• Salivation
• Facial twitches

Give one maintenance dose of calcium immediately. Give one dose of Calcarea Carbonica homeopathic for eclampsia. Remove puppies to safety temporarily, or supervise her if she is with them. Call your vet to put them on alert. Do both at the same time, not one before the other.

Moderate to Severe Eclampsia, go to the emergency vet now.

• Tremors, muscle twitching, can't walk straight
• Seizures, rigid body, unresponsive
• Temperature over 106°F
• Coma

Give one dose of Calcarea Carbonica homeopathic for eclampsia. It needs only touch the inside of her mouth. She does not need to swallow it. If she can't swallow safely, do NOT give oral calcium at this stage. Aspiration can be deadly.

Call ahead so the vet can prepare IV calcium before you arrive.

"Remove the puppies," doesn't mean forever. Colostrum is critical.

When I say remove the puppies, I mean temporarily, not permanently. Those puppies need colostrum from their mother within the first 12 to 24 hours of life. Nothing you give them later replaces it. Milk replacer keeps them alive in the short term, but colostrum is their immune foundation. Getting it into them matters enormously.

Once you have calcium in her along with homeopathic Calcarea Carbonica, and she begins to settle, usually within 30 to 60 minutes, try putting the puppies back on her, with someone present the entire time. Some breeders will muzzle the dam and have a second person hold her steady while the puppies nurse; others will wait until she's calmer and then supervise every second. Neither approach is wrong. What's wrong is leaving a compromised dam alone with newborns or giving up on nursing altogether because the first hours were hard.

Use your judgment about what's safe. If she's actively dangerous, get her settled first. But get those puppies back on her as soon as you can do it safely, even briefly, even with two people and a muzzle. This is hard, exhausting work, especially at the end of a long whelping. It is worth it.

A note on Calcarea Carbonica.

Calcarea Carbonica is a homeopathic remedy made from calcium carbonate. In homeopathic practice it is used to support the body's response to calcium deficiency and eclampsia symptoms. I keep it in my whelping kit and have used it for years alongside conventional calcium supplementation.

The key practical advantage when eclampsia is progressing past the mild stage: Unlike oral calcium, it does not need to be swallowed. A dose placed inside the lip or on the gum will work even when a dog cannot swallow safely. It is not a replacement for IV calcium, nothing replaces that in a true crisis, but it is something you can do in the minutes before you reach your vet, or alongside giving calcium paste or tablets.

You can purchase Calcarea Carbonica homeopathic for eclampsia at The Dog Breeder Store. Note: homeopathic remedies are not regulated or evaluated by the FDA for veterinary use. This is a tool from my own experience as a breeder, not a veterinary prescription. Many dairy cattle farmers use it on the regular to keep their cows from going down with what they call "milk fever" (eclampsia), because once down, they often do not rise again.

My vet said, "Just give tums."

Here's what that actually means.

Plenty of general practice vets will tell you to give Tums, and they're not wrong to say it, calcium carbonate is a legitimate calcium source and Tums is full of it. What they often don't tell you is how much your dog actually needs, and how that scales with her weight, which is where the advice falls apart in practice.

Download our free Eclampsia Quick Reference for exact dosing.

Important: Dairy is not enough on its own.

You've probably heard "give her ice cream" or "give her yogurt." Dairy does contain calcium, but less than most people think. In large amounts, it can cause significant diarrhea in the mom. A cup of plain whole-milk yogurt has about 275 mg of elemental calcium. Ice cream has roughly 85 to 170 mg per cup depending on the brand and fat content. These are useful between doses for a settled dam, but a single feeding will not reliably get a dog in mild Eclampsia to a therapeutic calcium level on their own.

Use dairy as a supplement to your actual calcium source, not as the source itself.

What I use in my nursery

For over five decades, I've watched the calcium conversation evolve, and I've landed on a two-phase approach that I recommend to every breeder I work with.

During whelping, I either use Oral Cal Plus Gel at recommended label dosing, or Nature's Farmacy Dogzymes Whelping Calcium Paste between puppies. After whelping, and the first few days: I use Nature's Farmacy Dogzymes Whelping Calcium Paste. It's a paste, it goes into the mouth, and it absorbs fast, which is exactly what you need when a stressed dam isn't eating and you need calcium in her blood quickly. It is also xylitol-free, and the label is dosed for exactly this situation. This is the brand I find palatable to my own dogs and that matches the dosing for lactation phase elemental calcium to the research. 

If I don't observe any symptoms of eclampsia developing, I rachet the dosing down somewhat to about one-fourth to one-half of what our free Eclampsia Quick Reference advises to give after an episode of eclampsia. If I see any early signs, especially in the mornings after they haven't eaten all night, I immediately give a dose of calcium paste for her body weight, and I go back to the dosing on our Quick Reference Guide. See my article called "Morning Watch" for more on this issue. And because mornings seem produce the most concerning symptoms, I usually get up during the night for the first week or two to give my girl food and calcium.

Once she's settled and eating regularly, usually days three to five, many breeders switch to a calcium and phosphorus supplement like Doc Roy's Healthy Bones tablets for ongoing nursing support. One thing worth knowing if you use this or a similar product: the labeled dose of one tablet per ten pounds of body weight delivers considerably more elemental calcium per day than the published veterinary standard for lactation maintenance (25 to 50 mg per kilogram of body weight per day). If you use a product like this, consider starting at a lower dose than the label suggests and watching how she does, rather than assuming the labeled amount is the calcium target itself, since it was not built around that specific standard. Our free Eclampsia Quick Reference covers this specific product dosing. I like this product because it is formulated well and my girls take it like treats.

All three are available at The Dog Breeder Store.

What I do not use in my nursery after whelping

Oral Cal Plus Gel - I will use this gel during labor only, as it is labeled with higher dosing for active labor, not lactation-stage crisis. If using during an eclampsia episode after whelping, calculate your dose from our free Eclampsia Quick Reference rather than the label's labor specific amounts. I also do not use the Oral Cal Plus Powder simply because I never know if my girl will eat all her food that it is mixed with; so dosing is hit and miss. I find the Doc Roy's Healthy Bones tablets easier to dose accurately.

CalSorb - this is a real, legitimate calcium gel labeled for extreme calcium deficiency, and some breeders and vets do use it. In our own experience, its calcium chloride base has a harsh, aversive taste that caused vomiting, a reaction other breeders have reported as well. If they vomit it, they don't absorb it. And I get the serious evil eye for giving it to them. We don't use it for this reason, though it remains an option if your vet recommends it specifically.

And keep a Tums in your pocket during active whelping.

If you don't have calcium paste, and you're between puppies during active labor and your dam seems off, moving differently, more agitated than the puppies alone would explain, a Tums tablet right then is cheap insurance for most dogs. It won't hurt her, and in early eclampsia, it can take the edge off while you assess. Just know it's a bridge, not a treatment. And that it can be divided for small dogs. 

Eclampsia is typically a lactation-phase development. However, I am aware of dams who have become violent towards puppies while whelping, not just afterwards. I never recommend allowing a dog to whelp or nurse puppies without having a calcium source at the ready and using it.

Want the full picture?

This article covers the essentials. For complete dosing charts, calcium sources, and eclampsia symptoms quick rerences, download our free Eclampsia Quick Reference. Download it, print it, laminate it, post it. It contains symptoms to watch for in easy charts to help you decide if you can treat this at home or neet a trip to the vet. It has all calcium dosing tables by weight for home sources of calcium. Emergency steps. Cabinet sources. Designed to be read at 3 a.m. when you're exhausted and scared.

Also look for Feeding For Breeding, our complete guide to raw feeding through pregnancy, whelping, and lactation, coming soon at The Dog Breeder Store.

A final word

If you take nothing else from this article, take this: when your dam is pacing, rejecting her puppies, snapping at them, or acting like a dog you don't recognize, don't judge her. Help her. Get calcium into her and get your vet on the phone. That dog isn't broken. She's asking for help the only way she knows how.

I have seen it go both ways. The breeders who understand what's happening save their dogs and their litters. The ones who don't sometimes don't get a second chance.

Keep your kit stocked. Know the signs. And don't hesitate to contact us.

— Paula Vandervoort, Breeder & Owner, The Dog Breeder Store

References

Merck Veterinary Manual. "Eclampsia in Small Animals." Accessed 2026. https://www.merckvetmanual.com/metabolic-disorders/disorders-of-calcium-metabolism/eclampsia-in-small-animals 

Baird, A., et al. "Successful Medical Management of Eclampsia in a Canine 9 Weeks Postpartum." Veterinary Record Case Reports (2025). https://doi.org/10.1002/vrc2.70194 

Joette Calabrese - All Creatures Great and Small - homeopathic calcarea carbonica in dairy cattle. https://joettecalabrese.com/blog/all-creatures-great-and-small/

This article is for educational purposes and does not replace veterinary advice. Emergency eclampsia requires immediate professional veterinary treatment. Always consult your veterinarian before beginning any supplementation protocol.