If I remember this correctly, it's leading the cattle up a ramp that gets progressively narrower to the point where only one cow can fit comfortably @ the end. At that point, the cow is struck on the side of the head with a bolt @ a particular pressure point, rendering death instantaneously. There were other details relating to the colour scheme and design of the ramp set-up that were meant to put the cow completely @ ease and pretty much leaving it not knowing what hit it. The whole point was that it wasn't a torturous method of slaughtering cattle.