I have a Weim who is brill with my 2 horses we also gave 2 old cats and he would never harm them.
We have 11 horses, (2, month old now, colts) cows, calves, 9 cats, and other dogs and our Weim is great with them. In fact 2 of the cats are really good friends with him and will lay in the sun with them. He wrestles with my 2 sons. He also hunts very well with my husband. Now if I could just get him to stop going useing the carpet for a bathroom, he would be the best dog ever!!!
in my experience, as long as the other animals are there first, and the Weim is brought in as a pup, (in my case as a two yr old), they will all do just fine. Weim males can be a little more difficult but having them neutered greatly alleviates any innate problematic behaviors. they are great dogs all around!