We may not assist an animal in delivering its young on Yom Tov, but we may sup-port [it]. We may assist a woman in childbirth on the Sabbath; we may call a midwife from place to place for her; we may desecrate the Sabbath on her behalf; and we may tie the umbilical cord. R’ Yose says: we may even cut [it]. And all requirements of circumcision may be performed on the Sabbath.