Training Dogs to Negotiate Fences and Cattle Guards

It's something we hope we never experience, but at some point are likely too, anyway: the high-speed intersection of running dog and barbed-wire fence. Or equally dangerous, running dog and cattle guard. But how to negotiate fences and cattle guards generally isn't something people specifically train for. I know I never have, but what I have done with all my dogs is introduce them to fences and cattle guards as puppies and let them figure out on their own the best way to negotiate their way. I've found that with enough practice in a controlled environment, eventually all my dogs learn how to get through a fence or around a guard without trying to run straight through it.

Introducing your pup to the hazards they'll face as dogs goes a long way to preventing those types of injuries, but so does being able to control your dog in the field. A timely "whoa" (for pointers) or a sit whistle (for retrievers) when your dog is thundering toward a fence or cattle guard can literally be a lifesaver. I had a bad experience with my very first retriever who wasn't trained to sit on a whistle, trying to jump a cattle guard at a dead run. It ended with a trip to the vet but luckily no broken legs. Ever since then when approaching cattle guards I heel my dogs and either send them through the fence on either side of the guard or I physically carry them across.

Thus far I've been lucky in that none of my dogs have been seriously injured crossing fences or guards. But how do you train or prepare for that scenario? Any specific techniques? Have you ever had a dog seriously injured on a fence or cattle guard?