Abstract: A cattle dehorner (10) comprises a power source (12), a power converter and control unit (14) and an operating unit (16). The power source (12) comprises an automotive-type storage battery. The power converter and control unit (14) comprises an electric motor (108) actuated by the power source (12), a pump (110) driven by the electric motor (108) and a hydraulic fluid reservoir (120). A valve (112) is provided for controlling the flow of hydraulic fluid to and from the pump (110) in the reservoir (120). The operating unit (16) includes a blade frame (22), a fixed blade (24) and a movable blade (34). A hydraulic cylinder (50) is secured to the blade frame (22) and functions to reciprocate the movable blade (34). The hydraulic cylinder encloses a spring (90) for retracting the movable blade (34) and a sleeve (92) for limiting the advance of the movable blade (34) under the action of pressurized hydraulic fluids supplied from the pump (110).