Specific Requirements for Head Restraint

Active restraint – specific requirements

If an active restraint is chosen, a number of factors can reduce the negative impact on the animal. The arms should fit closely to the wall so that they do not distract the animals as they enter. The area in front of and above the head restraint should be brighter than the rest of the box so that the animal is encouraged to place its head in the correct position. To prevent spooking the animal, and ensure it is restrained at the first attempt without inducing undue stress, the restraint should have an immediate, quiet action when activated. The power source operating the restraint must work quietly with no sudden noises – a hydraulic power source can be preferable to a pneumatic source.

Active, cantilever neck-yoke - resting position	Active, cantilever neck-yoke - restraining position

Part-passive restraint – specific requirements

The part-passive system has the same requirements as the active restraints. The stationary side should be designed to not distract the animal.

Part-passive - resting position	Part-passive - restraining position

Passive restraint – specific requirements

In the majority of cases, passive restraint systems will be the most appropriate. They should be carefully designed to not distract the animal. For example, internal fittings can be used to hang shelf systems. A head shelf is often fitted into an existing box and as such there are often limitations to the design because of the way animals exit the box. There are various designs of shelves used for passive restraint: a solid box, a fixed piece of curved metal, or a metal shelf held by a counter balance (Figures A-C). When swing doors are used for the exit of a carcase, a fixed shelf is suitable. However, if the exit door fully rotates and is the full length of the box, a counter-balanced shelf may be more suitable as the shelf drops with the weight of the animal’s head, facilitating removal of the carcase.

Animals can be encouraged into passive systems by lighting the area above the shelf so that it is brighter than the rest of the box and by closing any gaps which allow light in at the base or sides of the box, to avoid distraction.

Some lively animals have been known to use a shelf as a step to escape from the stun box, this can be prevented by careful placement of a bar across the top of the stun box, positioned above the withers. Shadows or contrasting colours in the box which may distract the animal from entering should be avoided.

Passive restraint designs

Rump-push

If an abattoir slaughters cattle of uniform size then passive restraint is an ideal system. However, if the size of the animals varies, the shelf becomes less effective as smaller animals have room to back away from the front of the stun box. A rump-push is a panel or gate which moves behind the animals to encourage them forwards. Rump-pushes can be operated manually, hydraulically or pneumatically depending on the power source available. Overall, a hydraulic system is usually best as this can apply the correct pressure and is quiet. The rump-push should ideally be positioned about 90cm from the floor.

When fitting a rump-push, it is important that it should:

• Be capable of applying suitable pressure, therefore positioning animals without causing pain or bruising
• Be positioned at a suitable height for the full range of sizes of animals encountered
• Not impair removal of the animal after stunning

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