Merck Manual

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Sorghum Poisoning (Sudan Grass Poisoning)


Barry R. Blakley

, DVM, PhD, Department of Veterinary Biomedical Sciences, Western College of Veterinary Medicine, University of Saskatchewan

Reviewed/Revised Oct 2020 | Modified Nov 2022

Sorghum poisoning is seen in horses, primarily in the southwestern US and Australia, after they have grazed hybrid Sudan pastures for weeks to months. The spinal cord softens and nerves degenerate in the spinal cord and brain. Also See also Cyanide Poisoning Cyanide Poisoning Cyanide kills tissues by lowering their ability to use oxygen. (Also see Sorghum Poisoning (Sudan Grass Poisoning).) Cyanides are found in plants, fumigants (such as disinfectants), soil sterilizers... read more .

Sorghum poisoning is characterized by lack of coordination of the hind end, inflammation and infection of the bladder, inability to control urination (incontinence), and loss of hair on the hindlegs due to urine scald. The lack of coordination may progress to limb paralysis. Reproductive problems, including deformed foals, can be seen. Affected horses often die from inflammation of the kidneys. Treatment with antibiotics may help, but a full recovery is rare.

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