They would have to tear me away from those dogs.
I have 3 dogs...German Shepherd...Chow terrier mix and a huge hound rottie mix. Trust me....all heck would happen if they ever did anything like that.
They wouldn't...They kissy face all the other pets...cats, horses, chickens,ferrets, etc. etc...
I'm a believer, that like a child, pets learn bad behavior from...the --so-called adult.
It's true most dogs would not be a threat to a horse, but the ones that are not probably don't learn that from humans, nor can humans necessarily stop them if they prove to have that kind of prey drive. A loose pit bull is dangerous to the whole neighbhorhood, whether he's going after the neighbor's pets, stock, chickens or children. They only have to get loose once, and most will. Maybe Cesar Millan can make them safe, but anyone short of his talent, I don't trust with a pit bull.
My own dogs (lab mixes) aren't a threat to the horses, but the horses are a threat to the dogs... They aren't allowed to be together or someone would get hurt.
My neighbor's dogs (a shepherd and a pointer) get into the pasture occasionally, despite the electrice wire I put up on their side. They mostly come to eat horse-sh__ and explore, but they have in the past played with the idea of chasing the horses. My two mares rolled them all the way home, as they scrambled to get out from under those hooves. I didn't fear for the horses, but I bet those dogs had some aches and pains from the experience.
My dog loves anything that breathes.
If I owned an animal that ever did anything like this, I'd kill it myself.
You simply cannot have an animal that is a threat to others.
Poor horse. It doesn't sound good. Just terrible.
Pets are animals. They do not have human traits. Dogs who have genetics which make them prone to destructive behavior do not learn such behaviors from humans.
It can be taught, but it cannot be totaly supressed.