Pig Heat (Estrus) Cycle Calculator
Predict the next heat dates and best AI/service timing for a pig (sow) from the last observed heat (cycle ~21 days).
Optimal service/AI timing: inseminate on standing heat, often a double service 12 and 24 hours after onset. Sows return to heat about every 21 days; the standing reflex to back pressure marks the service window.
Indicative planning figures based on published research averages. Local soil tests, varieties and weather change actual requirements — confirm with your agronomist or extension officer.
Breeders use the free Pig Heat Cycle Calculator to predict the next heats and time insemination correctly — the single biggest driver of conception rate.
About Pig Heat (Estrus) Cycle Calculator
Timing breeding to the heat (estrus) cycle is what makes the difference between a pregnant animal and a wasted service. Sows return to heat about every 21 days; the standing reflex to back pressure marks the service window. From the last observed heat, this tool projects the next three expected heat dates and reminds you of the optimal service window (inseminate on standing heat, often a double service 12 and 24 hours after onset.) plus when to do a pregnancy check if she isn't seen in heat again. Good heat detection and timing lift conception rates and shorten the calving interval.
How to use Pig Heat (Estrus) Cycle Calculator
- 1Enter the date heat was last observed.
- 2Read the next expected heat dates.
- 3Time service/AI to the recommended window, and pregnancy-check if heat returns.
Why use Pig Heat (Estrus) Cycle Calculator?
- ✓Uses the correct ~21-day cycle for pig (sow)
- ✓Projects the next several heat dates
- ✓States the optimal AI/service timing
- ✓Free, instant and fully in-browser
Frequently asked questions
How long is the heat cycle of a pig?+
About 21 days. Sows return to heat about every 21 days; the standing reflex to back pressure marks the service window.
When is the best time to inseminate a pig?+
Best timing: inseminate on standing heat, often a double service 12 and 24 hours after onset.
What if the animal returns to heat after service?+
A return to heat at the next cycle usually means she didn't conceive — re-inseminate at that heat. If she doesn't return, pregnancy-check from the date shown to confirm.
Is this tool free and private?+
Yes — free, no sign-up, and all calculation runs in your browser, so it works offline at the farm and your data never leaves the device.
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