semkuCattle Gestation Calculator
Estimate calving or breeding dates with a 283-day reference and sourced breed averages.
Estimated calving date
| Estimated date (General cattle, 283 days) | October 11, 2026 |
|---|---|
| 283-day reference | October 11, 2026 |
| General range, 279–287 days | October 7, 2026 – October 15, 2026 |
Planning estimates only, not guaranteed dates or a substitute for veterinary assessment. The displayed date range uses UNL Extension’s general 279–287-day gestation range for every profile; actual dates may fall outside it.
Sources and definitions
University of Nebraska–Lincoln Extension — How long does a cow’s pregnancy last?
283 days is common; the general range is 279–287 days, varying with breed and calf sex. Used for General cattle and the general range.
Council on Dairy Cattle Breeding (CDCB) — Gestation Length
Mean gestation length for cows: Holstein 279.0 days, Jersey 280.0 days. Heifer means and other breeds are not used.
Calculation rules
The breeding date is day 0. Forward adds the gestation length to the breeding date; Reverse subtracts it from the calving date.
General cattle uses 283 days. Holstein cow uses 279 days and Jersey cow uses 280 days.
The general range adds or subtracts 279 and 287 days. No breed-specific range is applied.
Only calendar dates are used, so time zones and daylight saving time do not change the result.
Frequently asked questions
- Where does 283 days come from?
- University of Nebraska–Lincoln Extension describes 283 days as common and a general range of 279–287 days.
- Where do the breed values come from?
- CDCB reports cow means of 279 days for Holstein and 280 for Jersey. These are not heifer or crossbred estimates.
- Does this calculator show a breed-specific range?
- No. The displayed date range uses UNL Extension’s general gestation range of 279–287 days for every profile. The Holstein and Jersey values are cow averages, not breed-specific ranges. Actual dates may fall outside the displayed range.
- Does reverse mode identify the actual breeding date?
- No. Reverse mode subtracts the selected gestation length to estimate a breeding date. The displayed date range uses UNL Extension’s general 279–287-day range, not a breed-specific range. It does not confirm the actual breeding date.
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Calculations run in your browser without sending your calculation inputs or results to the server. See “Privacy on this page” for information about access data.