Electric fencing is the cheapest, most flexible and quickest method. I seriously don't think we'll be doing much more barb-wired fencing, apart from our perimeter fences and maybe to split up our largest paddock.  Apart from that, I think we will be using more electric fencing. For a simple temporary fence, all you need is electric fence wire or tape, fence posts or clips to attach to an existing fence, an energiser and a battery (unless you get a mains powered energiser).  We usually run the wire/tape out around the area, and then position the posts at sensible intervals. We set up the earth, connect the energiser to power and turn on the fence.

 It took me a while to work out what the "earth" was for, but once you understand that, the rest of the fence makes more sense.  There are two ways of setting up the fence, either using an earth return wire or all live wires and an earth stake.With the earth return wire you alternate live and earth wires. With the earth stake, its just a metal rod in ground connected to the earth on the energiser.  Some people use really long stakes, like 6 m long stakes, but we just use an old tent peg.  So far we have been able to use just one or two live wires, with an earth stake. If you don't have an earth wire, you are relying on the ground to complete the circuit, which works ok if your soil is currently moist.Either way, when an animal touches the fence and contacts both the earth (wire or literally the change going into the ground) and a live wire, they complete the electric circuit and receive a shock.  The energiser itself is connected to the live wires, and to the earth wire or earth stake.  

Energisers come in different sizes designed to cover different nominal distances. When you first introduce cattle to an electric fence its a good idea to use an oversized energiser for the distance you're fencing.If the first shock they ever get is a strong one, they are unlikely to touch the fence again.  Cattle are very set in their ways, our house cow Bella will not touch an electric fence wire or tape, or even walk over a fence, whether it is energised or not, so we don't even have to use an energiser to keep her on the right side. Our neighbour's goats, however, can hear when the fence is on or off and are very opportunistic if they do notice that its off. If you have a lot of vegetation touching the fence, it will drain some of the charge, so its best to oversize the energiser in this case as well.