A practical calendar for livestock owners
GestationChart is maintained as a free due-date resource for farmers, ranchers, smallholders, youth livestock families, and horse owners. The aim is simple: turn a useful breeding record into a clear estimate, preserve uncertainty when exposure lasted over a period, and make the season easy to print or review.
The site combines a multi-species calculator, a cattle breeding chart, and a local herd planner. It requires no account. The reference values remain visible and do not change because of advertising or commercial relationships.
Where the numbers come from
The reference values come from extension publications, livestock research, genetic-evaluation information, and veterinary manuals. Each calculator result links to its basis. The chart and guides distinguish published figures from our cattle and sheep window methods.
Estimates and privacy
A published average cannot predict every animal. These tools do not confirm pregnancy, diagnose a problem, or replace veterinary advice. Confirm pregnancy and discuss individual due dates with your veterinarian.
Calculations run in your browser with no application backend. Single calculation inputs are in the page URL and may be processed by Cloudflare as part of the requested URL. The herd planner keeps its list in local storage on your device without uploading it. See the privacy policy for hosting and share-link details.
Help improve the tool
If a result or source appears wrong, use the contact page and include the calculation’s Share link. A reproducible breeding-date example helps distinguish a data issue from a counting-convention difference.