If the head is very large and / or the vulva too small and tight, an episiotomy may be performed. Notice the extended tongue. While episiotomies are routinely employed in human obstetrics, their use in cattle is uncommon. If the vulva is tight it may be stretched with the wedged forearms of the operator before the onset of the assisted delivery. It is important that the episiotomy incision is towards the 11 o'clock or 1 o'clock position to avoid incising or tearing into the rectal sphincter.
Seemann CW (1983)