I don't let Molly, the blind setter around the cows or horses because they are very interested in her, I think because of her color being red. She can't see anything and I'm afraid they might trample her. Gracey, the Siberian, likes to taunt them, which is also bad because they are so unpredictable. And longhorns hate dogs and will let them come right up to them and then trample them. I've been warned about letting a dog get in stomping distance of a longhorn. I've watched the cowdogs work and they run around the legs of the cow and bite them on the legs when they don't go in the direction the dog wants them to go and I can understand why they hate a dog. The only way for a 50 pound dog to get a 1200 pound cow to go in the direction it wants is to get in it's way and bite at the cows legs without getting trampled. It's very interesting to watch the dog's acrobatics to keep from getting killed while doing what it instinctively does.