Unfortunately, some farms are still troubled by problems brought about by stray electrical currents which exist on the farm electrical system's grounded neutrals, poor or faulty wiring, improper grounding, or faulty equipment.
Cows feel the currents produced by voltages they contact between two places.
These voltages are usually lower than voltages that humans can detect. It has been my experience that voltage levels of 0.5-0.6 are sufficient to cause adverse responses. The effect of stray voltage can be severe, but many of the effects also can be caused by other factors. Cows in early lactation may decline dramatically and peak yields may be disappointing. The actual decrease in milk yield may be related to reduced feed or water intakes, poor milk let-down, or increased somatic cell count.