In my experience very few animals actually will bite into a live line. I have seen gopher tortoises and both moles and gophers dig around them but I have never seen them do any real damage. once saw where a tortoise dug around a pole and cased it to fall over. Generally if you plant them 24 inches deep the only real and probable risk is humans. And if someone comes at it with a Ditch-Witch, backhoe or PHD odds are a conduit, anything less than RMC and a lot of luck, doesn't do you any good.

Of course if the ground is solid rock poles or skyhooks are the way to go.

I wouldn't worry about any irrigation or water lines. Usual plan is to figure out the type and size, lay in a supply of pipe and repair fittings and just count on running the Ditch-Witch through them. You chose your route to avoid the bulk of those you know about. No need to make more work. But in the end water line repairs are quick, easy and cheap. I don't even hand dig around them unless I can do it in a minute or two. I just try to hit them square so the damaged sections are short and make sure I know where the isolation valves are so they don't flood my ditch.