May 10, 2011

 Many cow-calf managers have been fighting the urge to get cows off the feed bill and back on pasture, says Jason Rowntree, a specialist in beef cattle and forage utilization at Michigan State University Extension.

But when is the right time to start grazing? With high rainfall and cool temperatures, turning cows out prematurely can result in overgrazing an already short supply of forage. Overgrazing stresses plants, depletes existing root reserves and requires a long recovery period. The lack of leaf area diminishes opportunities to take advantage of free solar energy, he says.

Consider turning cows out onto pasture with 6-8" forage height. One inch of plant should yield 250-300 lbs of dry-matter nutrition per acre, so 6-8" forage heights should produce total yields of a ton.

"The key in this is that the manager should only allow cattle to take half of that existing forage, most likely needing to move cattle daily or provide large enough pastures that the cattle do not graze the plant below the 3- 4" range," Rowntree says. Grazing below that height will slow recovery and decrease growth and performance.

Graze with low densities or large paddock spaces and increase stock density as the grazing season progresses or smaller paddocks each return, he adds. "Equally important, in early summer when forages grow explosively, cattle can return to the same pasture paddock in as short as 18 days. But in late summer and fall it may be as long 45 to 60 days."

Rowntree shows how to determine when to start grazing in this video.