Herein an end effector (2) of a robot arm is disclosed. The end effector is configured to participate in an animal related operation, and comprises an actuator (8) and a housing (10). The housing (10) is provided with a first aperture (12) at a first end portion (14). The actuator directly, or indirectly, participates in the animal related operation via the first aperture (12). The housing (10) is provided with a second aperture (16, 16', 16") providing access to an interior of the housing (10), wherein a passage (13) extends through the housing along at least part of the actuator (8), from the second aperture (16, 16', 16") to the first aperture (12). Thus, the housing may be flushed through for removing dirt.
