I don't know what it is about the horse world and dogs, but dogs are everywhere at equine events. Most horses don't seem to care, but I've owned two so far that had a homicidal hatred of everything canine. This always makes things awkward, because dog people can't seem to wrap their heads around the fact that my horse will straight up murder their pooch.
I acquired Jack as 3 year old stallion. Yes, I am slightly nuts.... Why do you ask? Actually, Jack had no clue he was a stallion, so it wasn't really a problem. I figured I'd just have him gelded come spring when the weather warmed up. Easy peasy, problem solved. Until spring came and I couldn't find a vet to do it.