When your dog first sees a horse, he’ll most likely react by chasing the horse or barking at it. That could be because the dog is afraid or nervous about the horse and reacts by trying to frighten the strange creature away by displaying aggressive behaviors.
Dogs are naturally predatory animals that hunt other species for food. On the other hand, horses are prey animals that instinctively take flight when they feel threatened. If your pet is not restrained the first time he encounters a horse, the chances are that Fido will set off in hot pursuit of Dobbin!