A Purdue University specialist says livestock producers can save time and money by using nature's harvesting equipment - animals.

"Anything we do to allow our four-legged creatures to graze in a pasture beyond the traditional grazing season is a cost-effective approach," says Keith Johnson, Purdue Extension forage specialist. "By having the animals harvest the hay into December and, perhaps, January, producers can reduce the cost of delivering hay bales to them every day."

Forage "stockpiling" involves setting aside about 25% of a pasture around mid-August, he says, leaving it undisturbed to grow, while mechanically harvesting or grazing the other 75%. Stockpiling can be done when producers use a rotational grazing system, where pastures are subdivided into smaller units - or paddocks - and livestock are moved from one paddock to another to give grazed areas time to regrow.

Annuals planted after winter wheat grain harvest can be components of the rotational grazing system in the late summer and into the fall, as well, Johnson says. Typical annual forage choices include sorghum-sudangrass, sudangrass, pearl millet, spring oat and forage turnips. Producers should be cautious when livestock graze sudangrass and sorghum-sudangrass in the fall because prussic acid, a toxic compound, will be released from freeze-damaged plant tissue.

Other points to remember when stockpiling forage include harvest timing and the dry matter needs of livestock. Producers should stop haymaking operations about 6 weeks before a killing freeze so forage can grow back and accumulate needed reserves for regrowth in the spring, Johnson says.

"Something that works well is allowing a hay field to grow its last crop and then bring in livestock for a post-dormancy grazing, instead of performing a post-dormancy harvest with equipment," he says.

How many days a paddock can be grazed depends on the amount of forage produced, each animal's dry-matter (DM) intake, and the number of animals grazing the paddock.

"It's not unusual for a cow that's just weaned her calf to require a daily DM intake of 2.5% her body weight," Johnson says. "So, for a 1,000-lb. cow, that's 25 lbs. of DM forage/day."

For more tips, visit www.agry.purdue.edu/ext/forages/index.html.
-- Steve Leer, Purdue University ag writer