STRAY VOLTAGE - EFFECTS OF VOLTAGE FREQUENCY, FLOOR MATERIALS AND WETNESS ON ELECTRIC CURRENTS THROUGH SWINE

An experiment was conducted to determine the current through pigs hous ed on different types of floor (woven wire, concrete, molded plastic, or plastic-coated metal) and under different flooring conditions (dry or wetted with urine). In a first trial, 10 pigs between the ages of 4 and 22 weeks were used to measure, at intervals of three weeks, the c urrent due to 2 volts of 60 Hz ac voltage applied between a clamp inse rted at the angle of the lips and the floor. The current flow was high er in wet than in dry conditions and increased with age on the four fl oor types, as did the hoof contact area with floor and hoof pressure o f pigs. In dry conditions, there was no measurable current flow on the two plastic floors. In a second trial, the effect of current frequenc y (60, 1000, 3000, 10,000 Hz) on current flow at 2 volts ac was tested on the same pigs at 19 weeks of age. On all floor types, except the d ry plastic ones, the current flow increased with frequency, the highes t values being on woven wire floor. In a third trial, current flow was measured on 10 non-pregnant and 11 pregnant sows at 2 volts ac, 60 Hz on the floor types and conditions described previously. Pregnant sows were tested at 40 and 100 days of gestation. There was no effect of s tage of gestation and the only effect of gestation was on plastic-coat ed floor where more current flow was observed with non-pregnant than w ith pregnant sows (2.3 vs 1.4 mA). The current flow through sows was a lways higher on wet than on dry floors. These data show how the contac t impedance between the floor and the hooves varies as a function of f loor conditions and can influence the amount of current through young and adult pigs.