Upon finding many of them in a pack, piss them off by firing your bow at them and then sprint - with them chasing - to the nearest Stormcloak camp.
Sit up on rock where you think that you will be safe* and watch the ensuing hilarity.
*She wasn't safe. It got very messy.
Ha! Saber cats are way, way faster than a sprinting PC. Unless you find them right next to a camp, this won't work. However, you could cast animal allegiance on them and then run to the nearest
IMPERIAL camp, and wait for the effect to run out

.
Ultimate way to kill a saber cat: cast animal allegiance, run to the nearest deep body of water, fus ro dah them into the drink. Watch the poor kitty drown. Can NPCs drown though?

*goes test*