Uhm, one thing about electric fencers and RFI is that if there is any flashover from wire-to-ground {say, at insulators on metal posts} the "signal" will be a lot more 'penetrating.' Run the fenceline at night and you may see and hear the problem.
Now, if you give cows there own internet access, {wcw.bovimania.cow is good} you can unplug the fencer for a couple of hours and the cows never notice!
