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Fast facts for grazing sudangrass

This undervalued forage option needs to be managed correctly, according to a Nebraska Extension beef systems specialist.

Elizabeth Hodges, Staff Writer

June 10, 2024

3 Min Read
Sudangrass
MANY TALENTS: Sudangrass is a jack of all trades in terms of grazing potential. In addition to the nutritional and regrowth benefits, it can withstand trampling better than other forages. stevanovicigor/Getty Images

Cattle producers may be looking for a summer annual to graze, and sudangrass could be the solution. This forage, if managed correctly, can produce 15% to 20% crude protein and be a good addition to a rotationally grazed system.

“I think sudangrass is undervalued because of its regrowth potential,” Mary Drewnoski, Nebraska Extension beef systems specialist, said at a recent University of Nebraska Cattle and Coffee webinar program.

On the other hand, if you are looking for an annual to graze late in the season or for stockpiling, pearl millet is a good option. Both pearl millet and sudangrass are drought-tolerant crops that have been shown to be valuable during times of little rainfall.

Managing production

If producers are used to grazing perennials and want to change to an annual forage such as sudangrass, there might be a mindset change needed. Drewnoski recommended stocking pastures early and at high rates with this forage once it reaches 2 feet in height.

When grazing sudangrass, it is important to be cognizant of the prussic acid risk. Prussic acid can be present in sudangrass that is less than 2 feet tall or after the first frost. This toxin, Drewnoski said, acts as a cyanide and can be lethal to cattle. But when managed correctly, it has shown to be a valuable forage.

Here are the fast facts for proper management of sudangrass:

Rotational grazing. Because of the rapid regrowth, sudangrass is best managed in a rotational grazing system. Drewnoski recommended having three or more paddocks for the best utilization of the crop.

Planting recommendations. Drewnoski recommended planting in late May and waiting 45 days postemergence before grazing in early to mid-July. With proper moisture, cattle can graze this roughage until September or before the first frost.

Water requirements. While sudangrass is drought-tolerant, if producers are in a drier season, it is important to focus on the yield of the grass because there might only be one grazing period available. If water is restricted in the area, it is important to accumulate growth early, not focusing on regrowth.

Grazing limits. Once the sudangrass has emerged, producers can stock the area 45 days later. To ensure that the forage is high-quality, cattle producers should make sure sudangrass is grazed down to no more than 10 inches after stocking the pasture. This ensures the grass will maintain quality and stay high in crude protein.

Other options. If producers are looking for a late-season forage to plant after wheat, for example, pearl millet is a viable option, Drewnoski said.

“With stockpiled forage, pearl millet does have some great options there,” she said, “especially if you are trying to graze in October, before it is completely winter-killed, because the millets do not produce prussic acid.”

If beef producers are looking to stockpile a forage, pearl millet has a waxy outer layer and can hold up better during the stockpiling period.

Backed by research

Drewnoski’s research at UNL looked at peak lactation cows, calves and stocker calves to monitor their average daily gain while on sudangrass.

With 10 days rest between grazing, they were able to get three animal unit months (AUMs) per acre.

“Peak lactation cows maintained their body condition on sudangrass,” Drewnoski said. “They came on the pasture at a 5½ [body condition score] and came off the pasture at a 5½.”

Their calves at 60 to 90 days old were able to gain 2 pounds per day during the grazing period. The heavy stockers that were also grazing gained 2.1 pounds per day, she added.

Drewnoski and her team will be conducting the research study again this year to gain more data on grazing warm-season annuals.

Learn more at beef.unl.edu.

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About the Author(s)

Elizabeth Hodges

Staff Writer, Farm Progress

Growing up on a third-generation purebred Berkshire hog operation, Elizabeth Hodges of Julian, Neb., credits her farm background as showing her what it takes to be involved in the ag industry. She began her journalism career while in high school, reporting on producer progress for the Midwest Messenger newspaper.

While a student at the University of Nebraska-Lincoln, she became a Husker Harvest Days intern at Nebraska Farmer in 2022. The next year, she was hired full time as a staff writer for Farm Progress. She plans to graduate in 2024 with a double major in ag and environmental sciences communications, as well as animal science.

Being on the 2022 Meat Judging team at UNL led her to be on the 2023 Livestock Judging team, where she saw all aspects of the livestock industry. She is also in Block and Bridle and has held different leadership positions within the club.

Hodges’ father, Michael, raises hogs, and her mother, Christy, is an ag education teacher and FFA advisor at Johnson County Central. Hodges is the oldest sibling of four.

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