Our dogs, a border collie and corgi, chased off the one and only bobcat I've ever seen here in a decade. I know they're here as there are people that get permits to shoot them and saw a couple drug out from the tree line.For future: I’d recommend keeping LGDs.
Edit to add: More than one
Those two dogs vs bear is a little different. The corgi runs about 10 feet back behind the border collie, who stands her ground. The last time I was right there and called them in. Four cubs were up in our trees, and momma was upset. We all backed off, and they came down and left. No damage that time.
Not downing LGDs, but a cheaper route sometimes works too. We didn't get them for this, though; it just so happens they naturally protect our property and keep the chickens safe.