Note position of the bottom of the adjustable side to prevent pressure on the leg joint.
Adult steer on the center track conveyor. Note that the conveyor is shaped to fit the steer's brisket (chest).
Center track double rail restrainer. This system is available for sheep, calves, pigs, and adult cattle.
A double rail (center track) conveyor restrainer system designed by the author is based on research by Geiger et al. (1977) and it is adjustable for a wide variety of animal sizes. Baby calves, sheep and large 225 kg (500 lb.) calves can all be handled in the same restrainer. For adult cattle, a slightly wider conveyor is used. The width of the moving conveyor that the adult animals straddle is 30cm ( 12 inches).
Standard V restrainer conveyors may cause petechial haemorrhages during electric stunning (Thornton et al., 1979; Lambooy, 1986). There is a possibility that this system may reduce bloodsplash and speckle in electrically stunned animals (E. Lambooy, 1987, personal communication). With the double rail conveyor animals are supported under the brisket and belly while straddling the conveyor so that even large wild calves will ride quietly. The double rail requires less space than a V conveyor restrainer and it is compatible with existing shackling and bleeding systems.
Proper design of the system is essential. The top of the conveyor is level with the floor of the entrance race. The animals walk down a cleated nonslip ramp which is on a 25 degree angle.
Veal calf entering the center track restrainer. For all species, it's very important to have a non-slip ramp with cleats. For adult cattle, a belly rail must be added (see diagram of cross section through the restrainer entrance).
This same ramp design is also recommended for V conveyor restrainers. The sides of the ramp must be closed-in and animals must not see light coming up through the bottom of the restrainer. A stationary leg spreader bar over the ramp and in the first section of entrance race guides the animal's legs to the correct position. Calves entered this system with less balking compared to a V restrainer. The conveyor is constructed from metal segments attached to a moving chain. Each segment is bent to form the double rail configuration. Total width of the conveyor frame is 21.5 cm (8 1/2 inches). The moving segments are 19 cm (7 1/2 in.) wide with a 7.6 cm (3 in.) space in the middle to accommodate the animals' brisket. For adult cattle, a slightly wider conveyor is used. The width of the moving conveyor that the adult cattle straddle is 30cm ( 12 inches). The total inside width of the stationary sides is 107 cm (42 in) and the width of the entrance race which leads up to the conveyor is 86 cm (34 in). The width between the belly rails is 69 cm (27 in) (see diagram).
To induce the cattle to stay still and ride quietly, the solid hold down rack MUST be long enough so that the animal entering the restrainer can NOT see out until it's feet are completely off the entrance ramp.
This system MUST have a solid false floor just below the animal's feet. Cattle will balk and refuse to enter if they see a steep drop off below the conveyor.
Adjustable sides accommodate different sized animals. The adjustable sides press lightly against the top portion of the animal's body. They are on pivots and the bottom edge of the adjustable side is slightly above the top of the conveyor. This provides room for the animal's leg joints. Pressure on the leg joints causes stress and discomfort. The pivot mechanism simultaneously adjusts the width between the sides and the leg joint space. For calves, the width between the adjustable sides can be varied from 51 cm (20 in.) to 25 cm (10 in.). The space between the bottom of the adjustable sides and the top of the double rail is 5 cm (2 in.) when the sides are spread 25 cm ( l0 in.) apart and 12.7 cm (5 in.) when the sides are spaced 45 cm (18 in.) apart.
Full size double rail restrainer for adult cattle.
Inner adjustable sides. The position of the adjustable sides in relation to the steer's body can be seen in the first picture on this page. The adjustable sides are on pivots like a parallelogram. For adult cattle, the inside width between the adjustable sides is 53 cm (21 in) for small cattle and 73 cm (29 in) for large cattle.
Another very important design feature is the solid hold down rack and the solid false floor. To keep the animal calm, the hold down rack must be long enough to prevent the animal from seeing out until it's rear feet are off the entrance ramp. The solid false floor prevents the animal from seeing the "visible cliff" effect under the restrainer. This greatly reduces the amount of animals balking and refusing to enter.
|Cross Section through restrainer entrance
before the animal reaches the conveyor
|Cross Section through the conveyor
and hold down
These diagrams illustrate dimensions for adult cattle. Dimensions for calves are given in previous text. For adult cattle there must be a belly rail to keep the cattle centered as they enter the restrainer. The belly rail makes the animal straddle the leg spreader bar and it prevents the animal from walking on one side of the leg spreader. The belly rail must not extend all the way to the floor. The animal's feet need space for walking.
Installing a spot light to illuminate the entrance to the restrainer will make animals enter more easily and reduce balking.
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