Case study: Challenges in diagnosing hydrocyanic acid toxicity in cattle

摘要

Fourteen of 19 Corriente roping cattle became acutely ill and died after consuming hay containing johnsongrass, and then introduced into a pasture of Tifton 85 bermudagrass (Cynodon dactylon Pers X C. nlemfuensis Vanderyst). The presumptive diagnosiswas hydrocyanic acid toxicity (HCN) due to consumption of the bermudagrass. Tifton 85 bermudagrass has been utilized extensively for grazing cattle in the southern United States for 20 years with no reports suggesting HCN toxicity. In this case there waslack of a thorough diagnostic workup, and there were discordant results between laboratories. This case emphasizes that producers should be aware of the potential for toxicity due to nitrates or HCN in any forage, but a complete and prompt diagnostic investigation with appropriate collection of fresh samples is imperative for a definitive diagnosis.