AUTOMATIC-ANALYSIS OF FEEDING AND RUMINATING BEHAVIOR IN SHEEP

Feeding behavior is generally measured by mechanical devices which graphically record the jaw movements (Ruckebusch and Bueno, 1972; Ruckebusch, Bueno and Latour, 1973; Bechet, 1978). Data-reading is long and does not furnish all the information avaliable. The authors propose an electronic technique which is more accurate and flexible and can be applied in many different ways. The movements of the lower jaw of sheep were detected with a variable inductance gauge composed of a 20 cm long solenoid, made from a copper wire (diameter = 0.04 mm) wound around a rubber tube 5 mm in diameter. This unit was flattened and then covered with a polymer to protect it before placing it around the halter noseband of the animal. This transducer was connected to an electronic unit distinguishing the electric signals corresponding to ingestion from those of rumination. The ruminating periods had to be recognized by the following concomitant criteria : a) the time separating 2 cycles of maxillary activity had to exceed 3 seconds ; b) each cycle had to include a number of jaw movements ranging from a minimum of 16 to a maximum of 128 ; c) both (a) and (b) had to occur at least twice in succession. The electric impulses identified by the computer were then covered to the memory bank which was consulted whenever necessary by means of a digital system. The number of jaw movements during ruminating or feeding periods was thus directly known after being determined by the device. With this equipment the authors obtained the duration of rest and ruminating or feeding periods throughout the day, as well as the starting and ending of each of these periods. Moreover, this equipment could be used on grazing animals by taking long-distance hertzian readings.