With a long, cool and wet spring, many cow-calf managers have been fighting the urge to get cows off the feed bill and back in the pasture. However, when is the appropriate time to put cows into pasture? The largest risk with high rainfall and cool temperatures is turning cows out prematurely results in overgrazing already short forage. By overgrazing, the plant becomes stressed, must deplete existing root reserves and then requires a long period of rest to recover. The lack of leaf area in turn diminishes opportunities to take advantage of free solar energy.
Generally speaking a good beginning point to consider turning cows out into pasture is 6- to 8-inch forage height. An inch of plant should yield between 250 to 300 lbs of dry-matter nutrition per acre. Thus, 6- to 8-inch 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- to 4-inch range. Grazing the plant below this height will postpone recovery periods ultimately decreasing growth and performance.
A final tip in this equation is to graze with low densities or large paddock spaces and increase stock density as the grazing season progresses or smaller paddocks each return. 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.
Resist the urge to turn out cows too early in the spring; forages must have enough growth to respond after a grazing event. Leaving enough residual in the pasture for expedient regrowth is crucial. Proper spring grazing management will determine your success throughout the season.
Source: Jason Rowntree, Michigan State University Extension