Abstract: A vent cutter for separating the end of the rectal passage from an animal carcass, the vent cutter including a housing having an air motor mounted therein, a rotary cylindrical cutter blade driven by the air motor and having a hollow tubular pilot pin axially aligned in the cutter blade, a water passage in the housing for directing water through the cutter blade, an air passage in the housing for drawing air through the cutter blade to discharge water and waste material from the cutter blade, each passage including an air pressure operated valve connected to respond to the increase in air pressure to the air motor to open the water and air passages when the motor is operating and a trigger operated air control valve for controlling the operation of the air motor.