Match grazing system with resources, types of cows

DUBUQUE, Iowa — No single grazing system will work for all cow-calf operations.

“I work with a lot of producers and we do a lot of different things,” said Mary Drewnoski, beef systems specialist and animal science associate professor at the University of Nebraska-Lincoln.

“What works for one producer doesn’t work for another because resources are different and that may be labor, equipment or types of cows,” said Drewnoski during a presentation at the Driftless Region Beef Conference, presented by University of Illinois Extension, Iowa State University Extension and Outreach and University of Wisconsin Extension.

In eastern Nebraska, Drewnoski said, corn residue is cheap.

“We can get that for $8 per acre,” she said.

Another option is oats and brassicas planted after corn silage harvest.

“It is high quality so we limit access,” Drewnoski said. “We gave 400 cows an eighth of an acre a day and they maintained body condition.”

The beef systems specialist discussed a research trial that included 80 cows that were managed in two different systems. One group was managed in a traditional way with spring calving.

“They went out on brome grass in the summer, we fed some hay until we got access to cornstalks, took them off stalks in March and fed some hay,” Drewnoski said.

For the alternative system, calving was moved to a July-August period.

“We took advantage of the stalks when we can from January to March, they went to a drylot until Sept. 1 and then out on oats that were planted after wheat,” Drewnoski said. “The goal was to have high quality feed when the cows were breeding.”

“In the drylot, we fed a ration of 55% distillers and 40% corn residue,” she said. “During gestation, we fed 14 to 15 pounds per head per day because the density of the diet was high protein and high energy and during early lactation we bumped it up to 17 to 19 pounds of dry matter.”

With the modified distillers grains at $200 per ton on a dry matter basis and the cornstalks at $50 per ton, the ration cost about $1 per head per day during late gestation and $1.26 during early lactation, Drewnoski said.

“We had very good conception rate and calving rate with the alternative system,” she said. “One weird thing is we got a lot of twins which is probably something to do with the quality of the oats and we’ve seen it consistently for three years.”

The researchers choose to calve the cows in July and August because they expected it to be dry.

“The first year it was not dry — we had five inches of rain while we were calving so we had a lot of mud issues,” Drewnoski said.

“We figured out we needed a plan if it was going to get wet and the change we made was fairly simple,” she said. “After the first 30 days of calving, we moved the older ones to a new location and that made all the difference.”

Oats maintain fairly good protein content well into the winter, Drewnoski said, even though they look brown and horrible.

“The problem was it took 2.5 to 3.5 acres per cow for 80 days of grazing because we were getting a loss of 87 to 104 pounds of dry matter per pair per day,” she said. “We had huge trampling losses and that cost us $3 to $4 per day.”

The calves in the traditional system were 100 pounds heavier than calves in the alternative system.

“I think this is the disadvantage of our fall calving system,” Drewnoski said. “The weather those calves are going into is harder on them and we didn’t have the growth rates I’d like.”

The researchers saw little difference in average daily gains of the calves which followed through to finishing.

“We were trying to shoot for the same backfat,” Drewnoski said. “The growth rate on the alternative calves was a little lower so we fed them a little longer, but overall there were not huge differences.”

Instead of calving in a drylot, Drewnoski recommends a perennial pasture if cattlemen have that opportunity.

“Annuals are a nice system, as well,” she said. “There are a lot of people who calve their herd on rye and that seems to work really well.”

Drewnoski also discussed a research project with 50 steers grazing in a field planted with 50 pounds of oats and three pounds of rapeseed. Half of the group grazed the field continuously and the other half were strip grazed and moved twice a week.

During the trial it got really cold and there was lots of snow.

“Where the cattle strip grazed, the oats caught the snow and it piled up, but where there was continuous grazing, the forage didn’t catch the snow,” Drewnoski said. “The crew got concerned so we supplemented both groups of calves for one day.”

The strip grazed calves, Drewnoski said, didn’t touch the supplement and the continuous grazing calves had the supplement gone within an hour.

“Because the quality had not been selected through by the strip grazing calves, they had all the good stuff still there to graze,” she said.

The cost to purchase rapeseed is cheap at $1 per pound, Drewnoski said.

“You get about the same forage production or more compared to turnips,” she said. “The oat and rapeseed mix makes a lot of sense because we get a boost in performance by adding the rapeseed and it also reduces the seed cost by $5 per acre.”