Dairy
Stray Voltage
There is a great deal of disagreement among researchers as to the exact voltage, or current level, that causes production or handling problems in dairy animals. It appears that behavioral changes, which might require additional labor, such as kicking off milking machines, could occur at voltages as low as 1.5 V. However, the large majority of cows probably do not demonstrate problem behaviors until voltages are about 3 or 4 V. These voltage estimates are based on total impedances of 500 or 1,000 ohms. Direct economic effects have been shown at voltages of 4 V and above, but only in a small percentage of cases where animals refused to drink for 36 hours (6 out of 90 animals).
Based on current research, cow contact voltages from low impedance sources should be kept less than 2 to 4 V. Other information on stray voltage can be obtained from USDA handbook number 696 entitled Effect of Electrical Voltage/Current on Farm Animals
