It's especially bad during the rut, the young bulls are the worst. They must think he's a wolf.
Tell you what, those rubber crowd control slugs do the trick. I usually find a small circle of skin with fur on it laying on the ground. In Alaska, it's legal to kill wildlife that is attacking your animals, but I don't want the hassle so I use non-lethal means.
I've been chased several times, and even hit one in the head with a small sledge the first time I had a dog-stomping incident.
When my fiancee was living in Wasilla his partner got chased underneath his truck out in the driveway. The Moose was using its front legs to try to dig the guy out from under the truck.