Prussic acid & nitrate problems could be substantial this fall on forage sorghum and millet
BROOKINGS, SD – Any time growers plant any type of forage sorghum for hay and/or livestock grazing, prussic acid is a concern. However, in the minds of most growers, prussic acid toxicity is a concern early in the growing season when forage sorghum plants are less than 18-24 inches tall. Normally, when sorghum plants grow taller than 18-24 inches, growers tend to forget about prussic acid because the concentrations tend to drop off dramatically and are no longer a danger to livestock, said Eric Mousel, Forage and Alfalfa Specialist, Millborn Seeds, Brookings.
Prussic acid is a form of hydrogen cyanide that is produced by the partial oxidation of methane and ammonia. Prussic acid often shows up in lethal concentrations in sorghums due to accelerated uptake of ammonia during the rapid growth phase that occurs prior to the plant reaching 18-24 inches in height. Once the sorghum plant reaches 18-24 inches in height, uptake decreases and concentrations dilute to the point where they are no longer toxic to livestock.
“Unfortunately, prussic acid problems in forage sorghums aren’t limited to early summer as it tends to rear its ugly head again in the fall on fields that have been hayed or grazed and substantial regrowth has occurred,” Mousel said. “Once again, these plants are growing quickly and when they are under 18-24 inches tall or so, prussic acid toxicity to livestock should be a concern for producers.”
Mousel explained that this year could be a red-flag for grazing sorghum regrowth.
“In most years, August rains will allow forage sorghum regrowth to quickly get above the 18-24 inch threshold reducing prussic acid problems dramatically. This year though, August has been really dry in a lot of the state and regrowth has been slow,” Mousel said. “In most fields in the state, unless you test your forage sorghum regrowth for prussic acid levels, I would not recommend grazing it. The risk for poisoning livestock is simply too great to take a chance grazing it.”
Mousel suggests the alternative option of haying the regrowth.
“Although prussic acid in forage sorghum hay can still poison livestock, producers can grind and blend this hay in with other roughages when feeding this winter. When blended at 4:1, the risk of prussic acid poisoning becomes very small. Grinding, blending, and feeding is a real pain, but that is the only safe way to use forage sorghum hay that likely contains high concentrations of prussic acid,” he said.
Millet regrowth on the other hand, may have problems this fall as well, Mousel encourages growers to have a nitrate test done before turning livestock out to graze millet regrowth.
“Although millets do not produce prussic acid, they do tend to accumulate nitrates in the regrowth when the soil is dry. Nitrate accumulation in millet regrowth is not as predictable as prussic acid accumulation in forage sorghums therefore; the best thing to do is have a nitrate test done before turning livestock out to graze any millet regrowth. Millet regrowth that tests less than 2 ppm nitrates is ok to graze however, if the millet regrowth tests higher than 2 ppm, grazing will result in dead livestock,” Mousel said.
Like prussic acid, nitrates will remain in the forage and can be toxic to livestock even if the regrowth is cut for hay. Therefore, haying, grinding and blending at 4:1 for feeding this winter is the alternative strategy to manage millet with high nitrates.
BROOKINGS, SD – Any time growers plant any type of forage sorghum for hay and/or livestock grazing, prussic acid is a concern. However, in the minds of most growers, prussic acid toxicity is a concern early in the growing season when forage sorghum plants are less than 18-24 inches tall. Normally, when sorghum plants grow taller than 18-24 inches, growers tend to forget about prussic acid because the concentrations tend to drop off dramatically and are no longer a danger to livestock, said Eric Mousel, Forage and Alfalfa Specialist, Millborn Seeds, Brookings.
Prussic acid is a form of hydrogen cyanide that is produced by the partial oxidation of methane and ammonia. Prussic acid often shows up in lethal concentrations in sorghums due to accelerated uptake of ammonia during the rapid growth phase that occurs prior to the plant reaching 18-24 inches in height. Once the sorghum plant reaches 18-24 inches in height, uptake decreases and concentrations dilute to the point where they are no longer toxic to livestock.
“Unfortunately, prussic acid problems in forage sorghums aren’t limited to early summer as it tends to rear its ugly head again in the fall on fields that have been hayed or grazed and substantial regrowth has occurred,” Mousel said. “Once again, these plants are growing quickly and when they are under 18-24 inches tall or so, prussic acid toxicity to livestock should be a concern for producers.”
Mousel explained that this year could be a red-flag for grazing sorghum regrowth.
“In most years, August rains will allow forage sorghum regrowth to quickly get above the 18-24 inch threshold reducing prussic acid problems dramatically. This year though, August has been really dry in a lot of the state and regrowth has been slow,” Mousel said. “In most fields in the state, unless you test your forage sorghum regrowth for prussic acid levels, I would not recommend grazing it. The risk for poisoning livestock is simply too great to take a chance grazing it.”
Mousel suggests the alternative option of haying the regrowth.
“Although prussic acid in forage sorghum hay can still poison livestock, producers can grind and blend this hay in with other roughages when feeding this winter. When blended at 4:1, the risk of prussic acid poisoning becomes very small. Grinding, blending, and feeding is a real pain, but that is the only safe way to use forage sorghum hay that likely contains high concentrations of prussic acid,” he said.
Millet regrowth on the other hand, may have problems this fall as well, Mousel encourages growers to have a nitrate test done before turning livestock out to graze millet regrowth.
“Although millets do not produce prussic acid, they do tend to accumulate nitrates in the regrowth when the soil is dry. Nitrate accumulation in millet regrowth is not as predictable as prussic acid accumulation in forage sorghums therefore; the best thing to do is have a nitrate test done before turning livestock out to graze any millet regrowth. Millet regrowth that tests less than 2 ppm nitrates is ok to graze however, if the millet regrowth tests higher than 2 ppm, grazing will result in dead livestock,” Mousel said.
Like prussic acid, nitrates will remain in the forage and can be toxic to livestock even if the regrowth is cut for hay. Therefore, haying, grinding and blending at 4:1 for feeding this winter is the alternative strategy to manage millet with high nitrates.
BROOKINGS, SD – Any time growers plant any type of forage sorghum for hay and/or livestock grazing, prussic acid is a concern. However, in the minds of most growers, prussic acid toxicity is a concern early in the growing season when forage sorghum plants are less than 18-24 inches tall. Normally, when sorghum plants grow taller than 18-24 inches, growers tend to forget about prussic acid because the concentrations tend to drop off dramatically and are no longer a danger to livestock, said Eric Mousel, Forage and Alfalfa Specialist, Millborn Seeds, Brookings.
Prussic acid is a form of hydrogen cyanide that is produced by the partial oxidation of methane and ammonia. Prussic acid often shows up in lethal concentrations in sorghums due to accelerated uptake of ammonia during the rapid growth phase that occurs prior to the plant reaching 18-24 inches in height. Once the sorghum plant reaches 18-24 inches in height, uptake decreases and concentrations dilute to the point where they are no longer toxic to livestock.
“Unfortunately, prussic acid problems in forage sorghums aren’t limited to early summer as it tends to rear its ugly head again in the fall on fields that have been hayed or grazed and substantial regrowth has occurred,” Mousel said. “Once again, these plants are growing quickly and when they are under 18-24 inches tall or so, prussic acid toxicity to livestock should be a concern for producers.”
Mousel explained that this year could be a red-flag for grazing sorghum regrowth.
“In most years, August rains will allow forage sorghum regrowth to quickly get above the 18-24 inch threshold reducing prussic acid problems dramatically. This year though, August has been really dry in a lot of the state and regrowth has been slow,” Mousel said. “In most fields in the state, unless you test your forage sorghum regrowth for prussic acid levels, I would not recommend grazing it. The risk for poisoning livestock is simply too great to take a chance grazing it.”
Mousel suggests the alternative option of haying the regrowth.
“Although prussic acid in forage sorghum hay can still poison livestock, producers can grind and blend this hay in with other roughages when feeding this winter. When blended at 4:1, the risk of prussic acid poisoning becomes very small. Grinding, blending, and feeding is a real pain, but that is the only safe way to use forage sorghum hay that likely contains high concentrations of prussic acid,” he said.
Millet regrowth on the other hand, may have problems this fall as well, Mousel encourages growers to have a nitrate test done before turning livestock out to graze millet regrowth.
“Although millets do not produce prussic acid, they do tend to accumulate nitrates in the regrowth when the soil is dry. Nitrate accumulation in millet regrowth is not as predictable as prussic acid accumulation in forage sorghums therefore; the best thing to do is have a nitrate test done before turning livestock out to graze any millet regrowth. Millet regrowth that tests less than 2 ppm nitrates is ok to graze however, if the millet regrowth tests higher than 2 ppm, grazing will result in dead livestock,” Mousel said.
Like prussic acid, nitrates will remain in the forage and can be toxic to livestock even if the regrowth is cut for hay. Therefore, haying, grinding and blending at 4:1 for feeding this winter is the alternative strategy to manage millet with high nitrates.
BROOKINGS, SD – Any time growers plant any type of forage sorghum for hay and/or livestock grazing, prussic acid is a concern. However, in the minds of most growers, prussic acid toxicity is a concern early in the growing season when forage sorghum plants are less than 18-24 inches tall. Normally, when sorghum plants grow taller than 18-24 inches, growers tend to forget about prussic acid because the concentrations tend to drop off dramatically and are no longer a danger to livestock, said Eric Mousel, Forage and Alfalfa Specialist, Millborn Seeds, Brookings.
Prussic acid is a form of hydrogen cyanide that is produced by the partial oxidation of methane and ammonia. Prussic acid often shows up in lethal concentrations in sorghums due to accelerated uptake of ammonia during the rapid growth phase that occurs prior to the plant reaching 18-24 inches in height. Once the sorghum plant reaches 18-24 inches in height, uptake decreases and concentrations dilute to the point where they are no longer toxic to livestock.
“Unfortunately, prussic acid problems in forage sorghums aren’t limited to early summer as it tends to rear its ugly head again in the fall on fields that have been hayed or grazed and substantial regrowth has occurred,” Mousel said. “Once again, these plants are growing quickly and when they are under 18-24 inches tall or so, prussic acid toxicity to livestock should be a concern for producers.”
Mousel explained that this year could be a red-flag for grazing sorghum regrowth.
“In most years, August rains will allow forage sorghum regrowth to quickly get above the 18-24 inch threshold reducing prussic acid problems dramatically. This year though, August has been really dry in a lot of the state and regrowth has been slow,” Mousel said. “In most fields in the state, unless you test your forage sorghum regrowth for prussic acid levels, I would not recommend grazing it. The risk for poisoning livestock is simply too great to take a chance grazing it.”
Mousel suggests the alternative option of haying the regrowth.
“Although prussic acid in forage sorghum hay can still poison livestock, producers can grind and blend this hay in with other roughages when feeding this winter. When blended at 4:1, the risk of prussic acid poisoning becomes very small. Grinding, blending, and feeding is a real pain, but that is the only safe way to use forage sorghum hay that likely contains high concentrations of prussic acid,” he said.
Millet regrowth on the other hand, may have problems this fall as well, Mousel encourages growers to have a nitrate test done before turning livestock out to graze millet regrowth.
“Although millets do not produce prussic acid, they do tend to accumulate nitrates in the regrowth when the soil is dry. Nitrate accumulation in millet regrowth is not as predictable as prussic acid accumulation in forage sorghums therefore; the best thing to do is have a nitrate test done before turning livestock out to graze any millet regrowth. Millet regrowth that tests less than 2 ppm nitrates is ok to graze however, if the millet regrowth tests higher than 2 ppm, grazing will result in dead livestock,” Mousel said.
Like prussic acid, nitrates will remain in the forage and can be toxic to livestock even if the regrowth is cut for hay. Therefore, haying, grinding and blending at 4:1 for feeding this winter is the alternative strategy to manage millet with high nitrates.
