Cattle Today

Cattle Today

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Jim Russell, Dennis Maxwell, Tracy S. Petersen
Iowa State University Extension Service

AMES, Iowa -- Iowa's cow-calf producers need only to look at their pastures when it comes to reducing winter feed costs.

Extending the grazing season can save producers 50 cents a day per cow, compared to feeding hay throughout the winter, according to Jim Russell, forage grazing specialist at the Iowa Beef Center at Iowa State University.

While extending the grazing season is simple to do, the decision hasn't been, Russell said.

"Some producers seem to make hay for beef cows because they've always made hay, without considering the costs," he observed. "It's traditional." He added that many beef producers tend to overestimate weather restrictions to extended grazing. In reality, he said, much of Iowa receives few major snowfalls, and those don't stick around forever.

"We found that cows will readily go through a foot of snow to find good quality forage," Russell said. "A quarter of an inch of ice will do you in, but that's when you'd use hay or some other stored feed for supplemental feeding."

Russell and others on the Leopold Center for Sustainable Agriculture's animal management issue team at ISU have been developing components of a year-round grazing system for 10 years. In this research, Russell has found that grazing one acre of cornstalks saved about 900 pounds of hay. Grazing one acre of late-summer residual forage, called "stockpiled forage," saved 1,200 to 1,700 pounds of hay.

Most recently Russell compared a traditional system of summer rotational grazing plus winter hay feeding in dry lots to a system of summer rotational grazing followed by winter strip-grazing of cornstalks and stockpiled forage.

"In the year-round system we fed 400 pounds of hay per cow," Russell said. "In the dry lot we fed 3 tons of hay per cow." The end results showed the cattle in both groups had equal reproductive performance.

The research was conducted at ISU's McNay Research and Demonstration Farm near Chariton. Russell noted that the required pasture acreages vary across the state, according to soil quality. In his research, Russell estimated that 4.25 acres of perennial grass-legume pasture and 2.5 acres of cornstalks were needed per cow per year. Of the perennial pasture, 2.5 acres would be needed for winter grazing. Fewer acres of perennial forage would be needed if more acres of cornstalks were available, or if soils were more productive.

Dennis Maxwell, livestock manager at the McNay farm, noted that stockpile grazing also saves in labor because neither feed nor manure need to be hauled.

"I've been very pleased," Maxwell said. "From my observations, the cows seem contented to be out grazing, even if it's raining or the snow is blowing. They seem to hold up quite well."

Year-round grazing requires some management decisions before the snow begins to fly.

"To correctly stockpile pasture, you need an optimum of 70 days of growth before the killing frost," Russell said. "Graze a portion of the pasture or take hay off it until early August, then let it grow until the killing frost in October." Beginning to stockpile too early provides greater quantity, but less quality in the forage. Russell also recommended fertilizing pastures in early August with 40 pounds of nitrogen per acre, which may increase forage yield by 500 to 1,000 pounds per acre.

Once cattle begin grazing the stockpiled forage, allow cattle onto a new area every 28 days. This prevents selective grazing of the highest quality forage and maintains a section of high-quality forage for springtime, when the nutrient requirements of spring-calving cows are the highest.

Producers should carefully observe the cattle, particularly for condition scores. Nutritional decisions, such as when to supplement feed, should be based on maintaining cows at a condition score of 5 on a scale of 9.

And for those days when cattle cannot graze due to the weather, have a back-up source of feed, such as hay, baled cornstalks or corn gluten feed.

Finally, for those who want to extend their grazing season this fall but haven't stockpiled forage, Russell suggested grazing on cornstalks, which are still the least expensive feed source on most Iowa farms.

Russell noted that even if producers cannot graze throughout the entire winter, they can save approximately $1,500 in a 100-cow herd for every month they extend the grazing season, whether it is in the spring or fall.

The Iowa Beef Center is ISU Extension's link to the beef industry. For more information, contact the Iowa Beef Center at or (515) 294-BEEF

Iowa State University Extension Service


Jim Russell, Iowa Beef Center, (515) 294-4631,

Dennis Maxwell, McNay Research and Demonstration Farm, (515) 766-6465

Tracy S. Petersen, Iowa Beef Center, (515) 294-9172,


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