A lot of it has to do with how easy it is to get to another buyer.  When the giant stockyards were in operation, the various packers kept each other in some sort of balance, and ultimately the retail price of meat worked back through the system.  Now it is more dependent on the proximity to an alternative market; if there is one main buyer at the only market for 300 miles, then he can pretty much set the price on any given day.  Long term, the market will eventually pull him back, as producers either exit the business or swallow hard and hire trucking to the neighboring state.  Short term, the consolidation of the packing business can allow one player to create big swings.  Look how much taking one  plant off line affected the short term market for Holsteins.  It's nothing new.  There are stories of how the value of a herd of longhorns could double or halve depending on when the next herd was due to arrive at the railhead.  There was nothing worse than getting your steers to town just as another herd was being loaded onto cars.The true long term price setter is still the retail price of meat.  Factor in all the international trade politics, prices for feed, land, fuel and labor, market speculators, interest rates, regulations, and everything else, and you can probably calculate what the price should be, and eventually the market will settle somewhere around that.  It's the short term factors that create the gyrations that make life so interesting.