First off, I'm glad your cat was okay... and I'm glad your dogs and you were as well. I have unfortunately hit the point myself that coyotes who will not head for the high hills that close to a human (and mind you, I did help with a rescue facility for canids at one time, including coyotes) will be unceremoniously removed from the gene pool, and go on to make a pair of very nice earmuffs.
I'm also just warning you - I don't know if I'd be very keen on letting my cat (or other small pets) out again for a while, if you can do so. Coyotes tend to hunt an area hard - once they become domestic animal eaters, they will try over and over and over again. This one's bold because it has succeeded in the past, and cats that live with dogs often make a very fatal mistake - they don't run. They stand their ground, because they really do think it's a dog.
But after I sat down and thought about it I can hardly believe that this coyote was so possessive and aggressive. Usually they run off at the sound of a dog. And the coyote had to come up into my yard to get to the pasture. AND this took place at 1:30 in the afternoon. These coyotes seem to be getting braver and braver and I'm not sure I like it!
You're now seeing the urban coyote at his/her full capacity, is what's going on. Really, truly, they are becoming the top predator in urban environments; the reason they don't fear is that other things (people/wolves/cougar) don't hunt them in these sorts of areas. There was an interesting study done a few years ago about coyotes in Yellowstone - reintroducing the wolf has truly affected the coyote population, with packs losing 25-33% of their members each winter. They also spend less time resting and more time on guard, and are much shyer than even five years ago.
One of the things that really may make a difference for cats in coyote predator areas is that they should NOT wear a collar with bells or tags. Coyotes quickly realize that the jingle is the dinner bell, and the cat's chances of survival are incredibly compromised.
Like I said, I'm glad Sport's okay. He's incredibly lucky to have three dogs who kept him from being carried off and killed, and a mom who can obviously whack a coyote with the best of them.

Remind me that if I come back in another life as a coyote, I should stay out of your yard when I'm hungry. *grin*
(And your Shepherd is a very handsome boy, too.)