This is not veterinary advice. Routine calcium isn't always needed when there are no symptoms. Many breeders find it anecdotally helpful during labor and to calm restless, anxious, or aggressive females in whelp or postnatally.
Signs of eclampsia (trembling, confusion, stumbling, seizure) require immediate veterinary care. Oral supplements won't act fast enough for this life-threatening drop in blood calcium.
The dose below is the maximum daily elemental calcium typically given post-whelping, representing standard practice among many experienced breeders.
Elemental calcium ≠ mg of calcium on a supplement label. See the product section for how much of each product to give.
During labor: divide the daily amount and give a portion after each puppy, starting after the first.
After whelping: divide the daily amount over 24 hours.