It might not have been an electric cable that caused the problem
An old dis-used metal water pipe could have been an electrical link between the ground / earth systems in two areas served by different electrical supplies. Effectively bonding the two areas together and thus both have the same potential as each other with current flowing through the pipe.
Then the pipe breaks under the paddock and the broken ends now are at different potentials, the pipe is now importing these two different potentials to the ground either side of the break. That could create a steep voltage gradient over a very small area of ground
An old dis-used metal water pipe could have been an electrical link between the ground / earth systems in two areas served by different electrical supplies. Effectively bonding the two areas together and thus both have the same potential as each other with current flowing through the pipe.
Then the pipe breaks under the paddock and the broken ends now are at different potentials, the pipe is now importing these two different potentials to the ground either side of the break. That could create a steep voltage gradient over a very small area of ground