I'll echo some of what has already been said here. We have elk, deer, antelope, and occasional moose and many miles of electric fence. After the first couple months here (we are now in our sixth year), we have had virtually no maintenance issues with our fence. We don't even have them kocking down polywire anymore. We've even had wolf turned back by 2-wire electric fence. Here's my recommendations based on our experience.
# 1: Make sure you have enough energizer power to do the job you're asking it to do. Dont' skimp on energizer capacity because of purchase cost. In the long run, oversizing your energizer is the lower cost option becasue of less future fence maintenance. Ground it properly!
# 2: Never leave any segment of fence turned off. Even if cattle aren't going to be there for several months, leave the fence on. Every other critter in the neighborhood will respect it a lot more.
# 3: Use 12.5 ga hi-tensile for all permanent fences. We never use less than 180,000 psi (minimum breaking strength) wire. The common farm & home and Gallagher wire labeled as 170,000 psi (maximum breaking strength) wire is really about 130,000 minimum breaking strength. It might be okay for just deer, but elk pop it like it was string.
#4: Use PowerFlex posts because of their flexibility to absorb animal impact plus they are self insulating. No insulators to get knocked off! If the cotter key attachment pin is installed properly, it is impossible for the wire to come off the post until you take it off.
Keep these guidelines in mind and you should have very few electric fence problems.