I know that our Mastiff/Golden mix (looked a lot like a great dane) was really good with our animals, he ignored the horses and cows and chickens...tri ed to share the pigs slop, was great with the cats and ferrets. My neighbor has an English Mastiff and she's great with all sorts of animals too, they have cats, 2 mojo's, a horse, a mini, and a bunch of goats! We didn't have many animals when we had our dane but she did well with the cows, cats and POA that we had while she was with us.
I tend to think like Zoo Crew, if they grow up with them, then they usually will be good around them. The only dog we've had so far that really can be a pain sometimes is Arisha my dad's husky/mal...but not in a bad way she likes to sit and watch (and help herd) the cows and will go out into the corral and sit on the manure pile and watch Finnigan (my 3 week old foal)...she doesn't chase them, or bark at them or try to hurt them...she just watches them.