Estimate a lambing date

Turn a mating date into an estimated lambing window.

Last updated About 7 hours ago

Open Tools, then Gestation Calculator. This tool is shown when the society’s animals are sheep.

The page estimates lambing from a mating date using a 147-day average. It says the dates are estimates, and that gestation can vary by ewe, breed, and pregnancy.

Calculate

Mating date starts as today. Change it, then select Calculate.

An invalid date shows Enter a valid mating date. Changing the date clears the previous result until you calculate again.

The result is a schedule. It is not saved on an animal record.

The schedule

The columns are Stage, Gestation day, Calculated date (estimated), and Planning focus. Dates are shown as a month, day, and year.

Stage	Gestation day	Planning focus
Breeding	Day 0	Record breeding details
Mid-gestation review	Day 100	Review nutrition and pregnancy management
Late gestation	Day 120	Begin late-gestation preparation
Lambing preparation	Day 135	Prepare the lambing area and supplies
Window begins	Day 142	Begin close observation
Estimated lambing date	Day 147	Average expected lambing date
Window ends	Day 152	Follow up if the ewe has not lambed

Estimated lambing date is the highlighted row. The window around it runs from day 142 through day 152.

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