Coffee Senna Poisoning in Cattle
By Travis Mays, Analytical Chemistry Section Head
Approximately 200 head of cattle were grazing on improved native Bermuda grass pastures in the Colorado River bottom. Vegetation also included a large number of oak trees, and a low number of nightshade, cocklebur, and coffee senna plants. Two 400 to 500 lb. calves were found down and unable to rise. Both calves died within 24 hours. No other animals were affected. History noted that both calves appeared normal upon gross necropsy. Some whole plant leaves that resembled coffee senna were observed in the rumen of one calf.
Microscopic examination of the rumen content was performed by the toxicology section at the Texas A&M Veterinary Medical Diagnostic Laboratory (TVMDL) in College Station. Coffee senna seed pod fragments and leaf material was observed in the rumen content from both calves. No evidence of consumption of nightshade or cocklebur was observed in either animal. Histopathology was performed on fixed tissues, including skeletal muscle, liver, kidney, small intestine and large intestine. Examined sections of skeletal muscle exhibited marked multifocal myofiber granular degeneration and fragmentation with interstitial edema and accumulation of a few scattered lymphocytes, plasma cells and neutrophils. The histologic appearance of the muscle lesion was consistent with that of coffee senna intoxication.
Coffee Senna (Senna occidentalis) is primarily found in east and south Texas and extends east to Florida and north to Virginia. It usually grows in sandy or loamy disturbed soil, often in colonies around pens or shade trees rather than uniformly distributed over a pasture. The plant has linear seedpods that are 4 to 6 inches long, tend to be erect and contain numerous compressed, dull brown or dull green seeds. Clinical signs of affected animals include diarrhea, weakness, “alert downers” (not depressed, will eat, but unable to rise), dark urine, and death. Once an animal is down, it generally will not recover, even though it is bright-eyed and continues to eat and drink.
To learn more about this case, contact Travis Mays, analytical chemistry section head in College Station.
Hart, CR, Garland, T, Barr, AC, Carpenter, BB, Reagor, JC. Toxic Plants of Texas. Texas Cooperative Extension. 2000. pp. 194-195.