i was asked by a fellow worker how to live trap a beaver. I know that it can be done, but never really thought it through. Off the top of my head i figured you could either build a castor mound inside the cage to lure the beaver in, or you could use some saplings as a food bait.
am i right?

Yes,

Or use a snare, or foot hold on long chain. Just more difficult to move and release.

thanks.
she has dogs and was worried that the dogs would attack a beaver in a foot hold. i agreed with her that a live cage would protect both animals.

Assuming live trapping means live and unharmed, as little injury as possible. Lots of ways. Snares with relaxing locks. Make sure the beaver can't snub up under water or wind up on something tight on land either. Keep them out of the sun on a hot day, or if in the sun in the water at least. Have caught and moved hundreds that way using a transfer cage with a quick release on the snare extension, but be ready to get wet. Hancocks or Baileys of course work fine too. Have unintentionally live trapped many dozens in cages with lure up on the bank. I like to drop in the cage somewhere narrow in 10 inch water with castor up on the bank behind the trap. The lure can be 5, 10 or 50 feet or more from the trap as long as the trap is in between the beaver and the lure. If you don't get him coming, you will take him going. Don't need a lot of blocking, just enough to keep him honest.

i dont think im allowed to use a cable snare on a beaver here in wisconsin... i will have to look into that.

I don't use many castor sets in the summer heat,,,,

Wisconsin is a lot like it is here in the Adirondacks, same terrain, same vegetation, same temps. I catch a very large percentage of beaver with castor, any month there is open water. I'm even hearing where some in Georgia are catching beaver with castor in the summer. Again there are so many ways. Snaring was something I did a lot of in the early 90's. I now prefer cage traps because it is faster and easier and equally productive in most cases. With cages there is no tear up, nothing for anyone to see, easy to hide, versatile. Not apt to interact with pets or kids either. Just an all around safe effective method, no transferring etc. as they are all ready to move.

Good commercial Jim!

Jim makes a great beaver trap. I have 14 or so of his traps and will probably be buying more.

Chuck