We have 5 strands of barbed wire around our field and we also have a electric fence on the inside of the post about 30 inches off the ground, that will hold any cow or calf as long as they have plenty to eat.

If I were to have sheep or goats I would have 2 strands of electric wire 1 about 12 - 16 inches or off the ground and then 1 wire about 24 inches or so above the lower one and run it around the perimeter of you land.

This would be an inexpensive way to start. Good luck with your project!