If your neighbor's cows are motivated to cross onto your property, I think you will need something that gives more of a jolt than any brand $50. fence charger. There has been a rent a bull here that seems to pretty much ignore fences when there is a heifer in heat anywhere up and down the road. 

I set up a system based on a Gallagher fence charger that says it puts out "6 joules". It puts out a jolt! I think that in your situation I would put a little more $$ into a charger and you may be able to get by with less investment in the fence itself. Even a single wire with a big charger on it will get their attention, especially if you have tall grass near it and possibly rubbing on the wire.

Yesterday I took a section of the fence down to move them to a different pasture. Even though the wire was down they were so aware of that fence that they would not pass between the few posts I left in place.

My fence was hit by lightning just one week ago. The charger looked like it exploded. I was amazed in that the local dealer I bought the charger from a few months ago replaced the unit with a new one at no charge. He said there is a 2-year warranty which includes lightning damage. I was impressed. Chargers tend to lead a rough life, I guess.

You may be much better off and spend less in the long run with a good, brand name, charger. jmho.

Jim at Dawn