I'll try to keep this short.
I've got a dog, he's always on a lead when we're out. I live rurally, the field next to my garden is the only route to reach any public footpaths to walk my dog. The field has a public right of way across it as it's on a designated national trail.
It's owned by a neighbour who has just put a horse on the land. My dog has no reaction whatsoever to horses, he ignores all livestock. The horse he's put on the field is clearly agitated by my dog, as I try to walk across the field (I pick my time, when the horse is the furthest away) the horse will run up and sniff at the dog's back end and sort of push him, I'm assuming this is a warning of 'get away'.
Again, my dog ignores totally as I swiftly walk across the field, but the horse will follow and keep pushing him until we're out the gate. It's happened twice now.
Obviously I don't want the dog, or me, to get kicked/attacked by the horse so I can't walk across the field again to risk it - would I be unreasonable to tell the owner his horse is causing an issue? Neighbour has form for being difficult.