Intoxica？？o espontanea por Sorghum sudanense em bovinos leiteiros no Rio Grande do Sul

an outbreak of sorghum sudanense (sudan grass) poisoning affected three cows from a dairy herd in triunfo, rio grande do sul, brazil. although s. sudanense has been used as a source of forage for cattle, sporadic poisoning occurs in association with management failures of these pastures. cyanogenic glycosides present in the plant may form hydrogen cyanide through hydrolysis and may cause livestock poisoning. twenty-nine holstein cattle were allowed to graze in an 800m2 paddock, in which lush sprouts of sudanense were 30cm high. animals were placed on pasture at evening and, in the next morning, most forage had been consumed and three cattle were found dead. no clinical disease was noticed. except by the presence of chewed sudan grass leaves near to the entrance of the rumen, there were neither macroscopic nor microscopic changes, samples of s. sudanense taken from different places in the paddock were positive when evaluated by the picrosodic paper test. such findings suggested that those three cows were affected by cyanide poisoning secondary to sorghum sudanense consumption.