About Tally Book

Tally Book is a set of free tools for people who breed livestock: cattle, sheep, goats, horses, pigs, rabbits, alpacas and llamas, plus dogs. It answers three planning questions quickly: when is she due, when could the whole group give birth, and when should the male go in to hit a target date?

Why it exists

Most gestation calculators online handle one animal and one date, and many printed charts still assume 283 days for every cow. Farmers asked for more: bull-in to bull-out windows, editable gestation lengths for their breed, herd lists they can print, and no app subscriptions or accounts. That is what this site does.

How we keep it accurate

Every number comes from a university extension service, a breed or research organisation, or a veterinary reference, and is listed on the methodology page. If you spot something wrong, please get in touch.

How it is funded

The site is free and is supported by advertising. There are no paid features and we do not sell any data. All calculations run in your browser.