— Tools · Breeding
Heat detection calculator
Enter the last standing-heat or recorded heat date. The calculator projects the next 18–24 day window (average 21 days) so you know when to watch, breed, or expect a return heat after AI.
How this calculator works
The bovine estrous cycle usually lasts about 18–24 days and averages near 21 days in cycling, non-pregnant cattle. Standing heat itself lasts hours, not days, which is why a predicted window only helps if someone actually watches.
If today’s date is past the first window and she is still open, the calculator rolls forward to the next 21-day cycle instead of leaving you on a missed date.
DairyLogs breeding records can store last heat and AI dates on the animal so this is not a one-off worksheet. Heat lists, PD due dates, and open days then sit on the same cow.
Related: Heat cycle timeline · Breeding
— FAQ
Breeding calculator questions
Turn heat dates into a herd list
Record heats and AI in DairyLogs. The next watch window, PD due date, and open days stay on the cow — ready for the next breeding manager on shift.