Hageman farms organically with his wife, Eleanor, near Calmar, Iowa. They have rotationally grazed in far-northeast Iowa since 1993, starting out with a dairy herd. In 2010, they switched their operation to beef, with about 75 cow-calf pairs, and finish the calves on pasture for the organic market.

The Hagemans enjoy networking with other graziers, and it was through pasture walks and research on their own they decided to try planting BMR sorghum-sudangrass on a steep hillside field.

Hageman said, “It needed to be renovated so I could plant alfalfa there next year. I wanted to smother out what was there, and that ground is too steep for corn – and farming organically, we don’t have the chemical options. The sorghum-sudan did an excellent job of smothering out the old forages.”

BMR sorghum is starting to generate more interest. BMR is a genetic trait discovered nearly 90 years ago in corn and started to become more popular in the 1990s.

In the late 1970s, the BMR trait was found in sorghum, and it was later discovered the trait also existed in sudangrass and pearl millet.

“In general, BMR was a groundbreaking improvement in warm-season annual grasses because it represented an opportunity for increased forage quality,” says Rhonda R. Gildersleeve, extension grazing specialist with the University of Wisconsin.

The BMR trait reduces lignin content and improves forage digestibility. Lignin is an indigestible fiber material in plants that provides structural support for plant tissues. Gildersleeve explains that reducing the lignin content increases the digestibility of forage crops and increases the availability of nutrients in the digestible plant fibers.

With less indigestible fiber and more nutrients available from the digestible fiber components, ruminant animals can be more productive on forage-based diets. Generally, preliminary studies show dairy cows will produce more milk, and beef, goats and sheep will gain more weight.

Hageman planted a 5.5-acre pasture with BMR sorghum-sudangrass at a rate of 35 pounds per acre on June 10 after a cutting of grass hay. On Aug. 4, he cut the 5-foot sorghum-sudan and got 18 5-by-5-foot bales of baleage. He cut the 5-foot-tall crop a second time on Oct. 15 and again got 18 bales.

“I thought it did well,” Hageman said. “We harvested twice and averaged about 3½ tons of dry matter per acre on poor ground.”

Hageman also planted an 8.5-acre field with barley April 30 and let the cattle graze. He had 56 cow-calf pairs on the pasture from June 26 to July 2. Then he planted BMR sorghum-sudan and corn in strips July 4, grazing 56 cow-calf pairs for 10 days starting on Aug. 23.

He was pleased with the results overall – including the tonnage – but it was very wet during that time, and they ended up with a lot of compaction damaging the stand.

After the cows grazed that area, the Hagemans seeded oats and radish for late-fall grazing.

Hageman also planted a 3-acre pasture with corn for the cows to graze. They planted 65,000 kernels per acre on June 19. They strip grazed 59 cow-calf pairs on the 5-foot-tall corn from July 30 to Aug. 3. For five days, the cattle got 50 percent of their forage needs from the corn, and they were on mature pasture for the other 12 hours of the day.

Although the palatability in BMR crops has been improved significantly, Hageman said that once, when his cows got out of the paddock fencing, they chose to graze corn over the sorghum-sudan.

Hageman says that both the BMR sorghum-sudan and grazing the corn in the field worked well for them, and they were pleased with the tonnage. Although the corn typically has a higher yield per acre, Hageman said on their operation they likely won’t use corn in that way again very often because they don’t want to deal with the repeated plantings needed to keep the system going all summer long.

“But it could be a way to eliminate the summer slump and increase pasture yield if pasture acres are limited,” he said.

Gildersleeve says it is important that each farmer choose what works best for his or her operation.

“From the forage quality standpoint, we would probably often recommend that farmers consider using BMR lines, especially if they are looking for increased forage quality, whether it is in silage or grazing,” she says. “However, forage quality may not be the only trait of interest; there might be other desired traits within any of these grass species that one might be interested in when comparing individual cultivars – for example, yield, resistance to pests and disease, lodging resistance, etc.”

When farmers like the Hagemans are deciding what to plant on their operations, Gildersleeve says to look at the benefits versus trade-offs each of the annuals have. For example, when comparing sorghum-sudangrass versus corn for a grazing situation, considerations should include:

• Cold tolerance for early planting, cold spring conditions, etc.: Corn generally does better because of genetic work to improve cold-soils tolerance while the sorghum family members all like a lot of heat.
  
  
• Regrowth ability after grazing: Sorghum-sudangrass is the best choice.
  
  
• Biomass yield: Corn generally has a greater yield than sorghum-sudangrass, maybe making it a better choice if the stand needs to be harvested for silage; however, a BMR sorghum-sudangrass might be a better silage choice than a non-BMR corn for quality.
  
  
• Grazing harvest efficiency: Sorghum-sudangrass has less waste.
  
  
• Prussic acid concerns: Corn would not create prussic acid issues, but there could be with sorghum-sudangrass.
  
  
• Drought tolerance: Sorghum-sudangrass is more drought-tolerant than corn.

“As you can see, there might be a number of things to consider, and we haven’t even gotten to planting equipment, nutrient management, pests/diseases or personal preference, all of which might also be important to any given farmer,” Gildersleeve says.

Hageman operates a total of 325 acres, of which about 125 is pasture. They grow oats, barley, alfalfa/hay and corn. The thing they still enjoy the most about their farm is turning cows out to a fresh paddock and watching them graze.  FG

Kelli Boylen is a freelance writer based in Iowa.

PHOTO: Iowa farmers Jim and Eleanor Hageman planted BMR sorghum-sudangrass to smother out weeds and provide forage. They were pleased with the results. Photo by Eleanor Hageman.