Abstract:
AUTOMATIC FEEDER FOR SHEEP J. W. U. BEESTON* I. INTRODUCTION In experiments conducted at this Laboratory it has been necessary to feed sheep at a number of specified times during the day. The labour cost of feeding sheep manually under these conditions can be high. Accordingly an apparatus was developed that would feed sheep automatically. The apparatus was designed to hold individual meals in separate feed containers, which are presented to the sheep at the appropriate time and the preceding container with any unconsumed residue is removed from the animal' access. s II. DESCRIPTION OF APPARATUS The major components of the apparatus are a platform holding the feed containers, motor and gears for driving the platform, a clock motor and switches to Fig. l. -General view of automatic sheep feeder in use. *Division of Animal Physiology, C.S.I.R.O., Ian Clunies Ross Animal Research Laboratory, Prospect, N.S.W., Australia. 357 activate the platform driving motor in response to the rotation of the clock spindle. Figure 1 shows the circular rotating platform which is divided into eight compartments each holding a feed container. The compartments are shaped to direct back into the feed containers feed that may drop from the sheep's mouth. The platform may be moved up and down the vertical shaft; the tightening of a set screw located in the boss of the platform allows the platform to be set at the required height. The vertical shaft is driven through a contrate pinion and wheel (8 to 1 reduction) by the platform drive motor (Figure 2). This is a geared electric motor that operates at 30 r.p.m. One rotation of the shaft of this motor moves the circular platform through one eighth of a revolution. This movement presents a different compartment of the platform to a sheep held in a suitable cage fixed in a position allowing the sheep access to one compartment of the platform. Simultaneously, the compartment to which the sheep previously had access is removed out of its reach. The synchronous clock motor (Figure 2) revolves once every six hours. A n aluminium disc attached to the shaft of this motor rotates at the same speed. The disc contains 36 holes that are equally spaced around the periphery. Pegs placed in these holes activate a switch that sets in motion the platform drive motor thus rotating the platform. Accordingly, the frequency with which the platform rotates may be regulated by inserting the requisite number of pegs into the aluminium disc. Rotation at intervals of 10, 20, 30, 40, 60, 90, 120, 380 or 360 minutes may be obtained. Operation of the platform drive motor depends on the action of two switches (Figure 2). Switch A is mounted on a lever pivoted at its top end to the base board holding the timing device. The arm of the lever is held by a spring against 358 the face of a cam which is rotated by the platform drive motor. When the cam rotates through one revolution the switch is moved away from the aluminium disc and back again. The switch is closed when one of the pegs on the aluminium disc depresses the actuating arm. Switch B is mounted directly on the base board and its actuating arm is depressed by the cam as it rotates. Both switches are connected in parallel in the active link of the A.C. power supply to the platform drive motor. When the platform drive motor is stationary, switch B is held open by the cam and switch A is open until closed by a peg in the aluminium disc. When the peg closes switch A, the platform drive motor starts and the cam is rotated until switch B closes. The cam continues and moves the lever, holding switch A, withdrawing it from contact with the peg, whereupon switch A opens. There is sufficient movement in the actuating arm of the switch to allow it to pass on the retreating side of the peg when the switch is returned to its original position by the cam. The cam completes one revolution and opens switch B, stopping the platform drive motor. The single rotation of the shaft of the platform drive motor as effected by the operation of these switches moves the platform through the required one eighth of a revolution. The operation is repeated when the next peg on the aluminium disc closes switch A. III. DISCUSSION The automatic feeder described here has functioned successfully during 3 months of continuous use. During this time it has been used. with sheep held in a conventional type of metabolism cage. Under these conditions it is possible to limit the animal' range of access to the feeder to one compartment. This may not s be possible with sheep held in other ways; additions to the apparatus may then be required to prevent the sheep taking feed from more than one compartment at a time. It was necessary on one occasion to fasten the automatic feeder to the floor to prevent it being moved bodily by a particular sheep. The automatic feeder may be readily modified to rotate at any specified time interval by varying the spacing of the holes in the aluminium disc or alternatively by using a clock motor that rotates at a suitable speed. The cost of materials used in construction of the apparatus was less than EA40. The nature of the construction is such that it may be carried out in any small workshop. 359