Why was Frostie considered the first frozen calf?

Frostie, a Hereford-Friesian calf born in 1973, was considered the first "frozen calf" because it was the first calf produced from an embryo that had been frozen, thawed, and successfully implanted into a surrogate cow.1

This achievement was the result of cryopreservation research conducted by the British developmental biologist Ian Wilmut. The successful birth of Frostie was a significant milestone that accelerated the development of commercial in vitro fertilization and embryo-transfer techniques for livestock, while also contributing to improvements in methods for freezing and thawing human embryos.1