Just had an episode

[CharlesHarris]

Barbed wire is excellent. Electrified cattle fencing would be ideal, but the pulsed square-wave noise from the transformer will come through the telly unless you install a healthy number of ferrite bead chokes close to the power supply, and another set where the coax for the telly enters the house.

Also sounds like a motion sensor connected to flood lights with loudspeaker and recording of growling, barking dog with warning sign (DANGER - Guard Dog On Premises) would be a welcome addition. Cheaper than feeding two Dobermans...