TRANSIENT STRAY VOLTAGE - IS IT DETRIMENTAL TO GROWTH-PERFORMANCE, HEALTH-STATUS AND WELFARE OF MARKET PIGS

The effects of transient stray voltage associated with an alternating current were evaluated in growing-finishing pigs from 9 to 22 weeks of age. Seventy-two pigs were assigned to 9 blocks of 8 animals each. In each block, the following treatments were randomly distributed: a con stant voltage differential created between the feeder or drinker and t he metallic floor (woven wire), at a level of 0 volt plus 2-volt pulse s (0 V-2 V), 2 volts plus 3-volt pulses (2 V-5 V), 5 volts plus 3-volt pulses (5 V-8 V), and a control treatment without any voltage differe ntial (0 V-0 V). The constant voltage was applied 24 h per day. The pu lses of 3 s duration were in the form of an increase in the amplitude of the constant 60-Hz signal. One pulse appeared every 20, 40 and 100 s during the hour following feed distribution and every 60, 120 and 30 0 s during the rest of the day. The animals were fed ad libitum and re ceived fresh feed twice per day. Once during the 2-week periods at 9-1 0, 13-14, 17-18 and 21-22 weeks of age, the behaviour of the pip was r ecorded during the hour following the two daily feed distributions. An imal weights and blood samples were taken every 2 weeks, from 9 to 21 weeks of age. No significant effect of transient stray voltage on any of the variables measured for the feeding, drinking, sitting or lying activities was found (p > 0.05). At 9-10 weeks of age, the number of r ooting bouts was higher for the 5 V-8 V treatment (p = 0.03) and the n umber of events of butting the penmate was higher for the 2 V-5 V trea tment (p = 0.05). Although the water and feed intake did not differ be tween treatments (p greater-than-or-equal-to 0.39), the average daily pin of the control group was lower than that of treated groups (p = 0. 04) at 9 and 10 weeks of age, while the pigs submitted to a 2 V-5 V tr eatment had a higher daily gain than the pigs in the other treatment g roups (p = 0.05) at 17 and 18 weeks of age. Finally, the frequency of gastric ulceration and the metabolic profile were not affected by the treatments (p > 0.05) except for the CO2 and total protein concentrati ons (p less-than-or-equal-to 0.04), where treatment effects were incon sistent among ages. Consequently, under the experimental conditions of the present study, no major impact of transient stray voltage on the health, growth or welfare of fattening pigs was observed.