Farmers and ranchers across the U.S. have a love-hate relationship with wildlife. For many ranch families, one of the perks is seeing wildlife, from big game animals to bluebirds, sharing their pastures and range with their livestock. On the other hand, several hundred over-wintering elk can eat up a lot of forage meant to take your cows through the winter. Then there's the headache of fence maintenance after the elk herd passes through.
If you want to allow wildlife access to your property, but minimize fence maintenance, it pays to design wildlife-friendly fence systems and management.
When we moved onto a central Idaho ranch, there were already some electric fences in place, but they'd been badly beaten up by the local elk, deer and antelope populations. A lot of barbed wire fences had down wires and broken or bent posts. Many ranchers in our valley had tried electric fencing, but gave up due to repeated critter damage.
Assaying our situation
We started looking at animal travel patterns and behavior to determine how to more effectively use electric fence for management in the face of heavy wildlife pressure. One thing we'd learned on our Missouri farm, with its heavy white tail deer population, was to never turn a fence off.
A lot of electric fences on rangeland use battery energizers; when the cattle leave at summer's end, the chargers are taken away. This leaves the fence non-energized for several months and the wildlife lose any respect for the fence gained over the summer. So, when spring comes, the fences are wrecked.
Simply adding solar panels to the energizers and leaving them on all winter can maintain year-round respect from wildlife. Our number-one wildlife policy here is never turn off a fence.
Common thinking has been to try to build a fence stout enough to stand up to animal impact. We design fences to flex with animal impact.
When we arrived, the perimeter fences on our pivots were four-strand, hi-tensile with the top wire at 45 in. When elk hit that fence, they usually hit it with their full body force right across the chest. We've since dropped all the fences to two-wire with the top wire at 30 to 32 in. Elk hit those fences with their legs and deliver a lot less impact on the fence.
The bottom wire on our fence is at 18-20 in., which allows antelope to shoot right under it without difficulty. Having watched antelope repeatedly bounce off barbed wire fences trying to cross them, I know ours are a lot more humane.
The existing fences used either steel T-posts or ⅞-in. fiberglass with little flexibility. When elk hit the fence with steel posts, insulators broke or popped off; then the fence was dead shorted on the post. If the insulators were top quality and stayed on, the T-posts were often bent over at ground level.
Meanwhile, the fiberglass posts were yanked out of the ground and often twisted end over end. On a fence with both hot and ground wires, this was another dead short.
A composite answer
All our fences now use PowerFlex® line posts, a very flexible wood-plastic composite that will bend over to nearly ground level and pop back up to its original position. Their textured surface holds them in the ground much better than slick fiberglass posts. The hi-tensile wire is attached with a long-tailed cotter key that we lock around itself so the wire can't be pulled off the post.
We also use stronger tensile-strength wire than most farm and home store wire. With about 50% greater breaking strength, these fences can take a lot more impact. With flexibility in the line posts, the fence rebounds easily from animal impact. The original fences here were lower-grade wire, and we still repair some breaks each year where that wire is in place. We have yet to repair a wire break where the higher-grade wire has been used.
For intensive management, we also use a lot of temporary fences that get moved every few days. Early on, antelope gave us a lot of problems, so we switched from polywire to high-visibility polytape for just a few months. Once they understood what electric fence was, we switched back to polywire, with few problems since. We knew we had our wildlife well trained this winter as we watched a string of 20 running elk stop for a single polywire, then politely jump it.
You can effectively utilize both permanent and portable electric fencing even if you have heavy wildlife pressure just pay attention to the details of design.
Jim Gerrish is a grazing management consultant based in May, ID, and former lead pasture researcher at the University of Missouri's Forage Systems Research Center in Linneus. Reach him at 208-876-4067, firstname.lastname@example.org, or visit http://americangrazinglands.com.