Grain sorghum stover compares favorably to corn regarding fall & winter stalks grazing, and livestock producers are encouraged to utilize corn and sorghum crop residues remaining after harvest.

Both corn residue and sorghum stover can be good nutrition for mid- to late-gestation cattle following fall grain harvest. Sorghum leaves have similar quality to corn husk and leaves; however, just like corn residue, the quality decreases over time.

Although both residue crops provide the highest nutrient content when grazed soon after grain harvest; it is highly recommended to prioritize grazing corn stalk fields first. Corn leaves tend to detach from stalks within one to two months after harvest and then blow out of stalk fields. This then dramatically lowers the nutrition remaining for grazing. In contrast, grain sorghum stover leaves remain attached to their stalks much longer into the winter and early spring; thus retaining their grazing nutritional value longer.

Previous grain sorghum yields can be used to set optimum grazing stalking rates. For example, grazing rates might be 1 acre per cow per month for every 100 bushels of grain sorghum harvested this fall.

Unlike corn residue, grain sorghum stover has a threat of prussic acid toxicity immediately following a frost, since sorghum plants are often still green at harvest.

So, delaying grazing turnout until 7 days, after plant killing freezing temperatures, will reduce prussic acid toxicity. Sorghum stover’s higher nutrient stem content may make it more prone to nitrate toxicity risk especially on previously drought stressed fields if the cattle are forced to graze the lower parts of the stems.

Sorghum stover usually has less lodging than corn residue, so mud and trampling field losses are generally less with sorghum during wet falls. Finally, spilled sorghum grain is likely safer than corn and not as likely to cause acidosis or founder as corn grain.

More crop residues research information is available on the cropwatch.unl.edu and beef.unl.edu websites.

By Todd Whitney

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