Restraint & weighing systems

Restraint & weighing systems

At certain times in the Management Calendar the use of restraint systems will need to be employed to enable specific treatments to occur safely, e.g. velveting, drenching, tuberculosis testing, vaccinating, etc. Deer restraint systems are only to be used by people who are experienced in operating them. At times deer can become agitated when handled in the shed or race, and so it is important that the handler is confident in operating the restaint system.

Forcing or sliding gates are often used in the race leading to the restraint system so deer cannot push back down the race and escape.

Restraint system regulations
There is specific regulatory detail related to restraint systems design and their use in the deer code of animal welfare.  The minimum standards related to restraint systems are listed below, however more detail and information can be found within the code.

  • Restraint equipment used must be maintained in good working order.
  • Restraint equipment must be used appropriately in order to minimise the risk of injury or unnecessary pain or distress to deer.
  • Restraint equipment used must be suitable for the class, age and type of deer being handled.
  • Operators must be fully conversant with the safe operating procedures of the restraint equipment.
  • Deer must not be held in a restraint for more than the time required to carry out the procedures for which they are being restrained.
  • Deer must be able to be rapidly released from restraint equipment.

There are three main types of restraint systems used in New Zealand which are the bale, crush, or cradle. Each device is described below.

Crush
A crush is of very similar design to the bale (described above). The main design difference is that one of the side walls or panels is moveable and the handler is able to force the deer onto the fixed wall which restricts movement of the animal. Once the animal is safely restrained, treatments can be administered safely.

Some crushes use hydraulic rams to hold the wall in place. These devices are expensive, but take less strength to operate. Other crushes hold the wall in place by the handler physically pushing the wall in, and then locking it in place.

It is common for the inner walls of the crush to have thick vinyl coated padding to provide better restraint of the animals, and added comfort to the restrained deer (photo below of hydraulic crush open so the deer can enter, and closed to show how the crush restricts animal movement).

As with the bale some parts of the animal are difficult to access when using a crush, e.g. feet.

Again it is important that only experienced personnel operate the crush, and they are confident in its use.

deer cradleCradle
The cradle is a much more complex design than the other restraint systems described above. It consists of a box construction with sloped inward (bevelled) walls at the bottom. A tunnel or ramp for animal access leads up to the suspended cradle. A removeable floor can then be released from beneath the deer, which means the deer is held by it's torso by the bevelled walls, and the feet are held off the floor below. The animal is held in the crush by its own weight.

If the crush is located high enough off the shed floor, then the feet can be accessed and treated from below. Other parts of the deer are accessed through removeable panels. The deer can then be released out onto the yard floor by swinging out an entire wall of the cradle.

It is essential that operators operators of this restraint device are experienced.

Bale
This is the most inexpensive of the restraining devices in that is the most simplest construction. It consists of a box construction which holds one animal at a time. A hole is located at one end or on the side which the animal sticks its head through. The animal is then restrained by the handler by holding the head and neck at a slight angle. The animal can then be released by opening the panel at the front. This type of restraint system is good for quick treatments like vaccination or drenching, however access to other parts of the body are limited for further treatments. A good deal of strength is required for large animals, and damage to velvet antler is common.

weigh bridgeWeighing systems
Regular weighing of individual animals at key times within the management calendar will aid productivity gains. A good set of scales within a deer shed is vital if production gains are sought. Scales are often incorporated in the restraint system to record individual animal weights for management purposes. There are many commercially available systems in use in New Zealand sheds.  Some examples can be found on the Animal Handler, Gallagher and Tru-Test websites.

Further information

Safe, practical deer yards, AgriQuality, 2005

Left: A Hennan Engineering automatic weighbridge. http://www.animalhandler.com/weighbridge