Floods and the late snow in the MIdwest killed over a million head of cattle from what I heard second hand (talking with my nephew over 4th of July). Particularly hard hit were the calf's in the cow/calf combos and cattle in Backgrounding Operations from what he said. That would hit the supply side starting about June and running through next summer.
China's pig population has been decimated from swine flu. That's doesn't effect us directly since little of our pork gets exported to China due to a particular growth hormone we use that's banded in China and the EU. IT has put overall upward pressure on prices though.
I suspect though that demand has more to do with it than any supply side pressures. 'Junk' meat continues to grow in popularity. It's great if you like chops and loins, because those are in lower demand, but what used to be junk is now in high demand. I regularly see flank steak and flap meat at prices higher than New York and RIb Eye in the market.