The drought-spawned exodus of cows from the Southern Plains is one for the ages. Depending on who's running the sort gate, 750,000 to 1 million head of beef cows will have left Texas alone by the end of this year. Through the summer, some reports had the Lone Star State migration pegged at around 600,000.

According to Derrell Peel, Oklahoma State University Extension livestock marketing specialist, beef cow slaughter in federal Region 6 (Oklahoma, Texas, Arkansas, Louisiana, New Mexico) is averaging 150% of year-ago levels for the past few months. Year-to-date beef cow slaughter in the region, which corresponds to the nation's worst drought area, is 123% above year-ago levels.

Year-to-date beef cow slaughter numbers for all other U.S. regions has declined 6%, resulting in a total national beef cow slaughter rate that is 101% of last year.

However, beef cow slaughter outside of Region 6 is 4.5% more than year-ago levels for the past eight weeks. Plus, Peel says significant numbers of cows have moved out of Oklahoma and Texas to other regions. "This likely means that cow culling for the remainder of 2011 will not follow typical seasonal patterns, either within or beyond the exceptional drought area that is federal Region 6," he explains.

Throughout the drought areas, evidence suggests that most of the cows normally culled for age or productivity reasons have long since moved to market and are part of the increased U.S. slaughter rates. Reports indicate that many younger or still productive cows from drought-ravaged areas have been sold, either to slaughter or to new owners in other regions.

"Though most of the normally culled cows already have been sold, continued dry conditions will presumably force additional cow liquidation through the fall," Peel says. "One would presume that most producers have by now determined if it is feasible to keep cows through the winter or not, and that additional movements might be at a slower pace than was seen during the summer months."

Moreover, some cattle producers are reporting significantly reduced pregnancy rates as a result of drought stress. Peel believes this may lead to additional culling this fall.

"America's total beef cowherd will decrease by 2-3% this year," Peel says. "The regional impacts will be more dramatic, with herd growth likely in the northern Great Plains states and northern Rocky Mountain regions, with double-digit reductions in Texas and Oklahoma."