Learn more about Yoke
A bow yoke is a shaped wooden crosspiece bound to the necks of a pair of oxen, or occasionally horses. It is held on the animals' necks by an oxbow, usually U-shaped, that also transmits force from the animals' shoulders, hence the name bow yoke. A swivel beneath the centre of the yoke, between the animals, attaches the pole of the vehicle (when the animals steer the vehicle) or chains that are used to drag the load.
A head yoke is a yoke which fits onto the head of the oxen and has carved out sections which the horns fit into. The yoke is then strapped to the head of the oxen with yoke straps and ox pads for cushioning on the oxen's foreheads. The yoke is held on in that manner, it does not rest on their necks. A tug pole is held to the bottom of the yoke using yoke irons and chains. The tug pole can either be a short pole with a chain attatched for hauling or can be a long pole with a hook on the end that has no chain at all. Sometimes the pole is attatched to a wagon and the oxen are simply backed over this pole, the pole is then raised between them and a backing bolt is dropped into the chains on the yoke irons in order to haul the wagon.
Although both yokes are effective a bow yoke needs far less maintenance since a head yoke needs to be constantly shaped to fit the animals horns. However a head yoke is better for teaching animals to stand quietly and avoid fighting because they cannot move their heads around freely.