Stray Voltage.
This is a very aptly named problem, in that it applies to any two objects that have electrical potential between them that ideally should not have any voltage difference between them. How much does it take? In general, we are always hoping for zero voltage, however, almost any animal can easily feel anything at 0.5 volts or higher. We could feel it too, but we usually have shoes or boots on and sometimes gloves. Lush says he finds this all too often and has even seen it run as high as 9 volts of current. Just imagine touching your tongue to a 9 volt battery.
Leakage from the power lines. Its impact is well documented on cows. We think, humans are super organisms! 
If stray voltage can affect dairy cows, alter their behavior, milk production, reproduction, it can do the same to us too!
If stray voltage can affect dairy cows, alter their behavior, milk production, reproduction, it can do the same to us too!Not just power lines, we are now surrounded by mobile towers, wifi towers, bluetooth devices.
The soundness and repeatability of scientific research and the success of its practical application has been validated over the past 25 years on over 9000 stray voltage investigations on farms in Wisconsin.
Read more here:https://mrec.org/files/2016/06/2016.Reinemann.ResistanceAndExposureRisk.pdf
