Cerebrocortical necrosis in ruminants: effect of thiaminase type 1-producing Clostridium sporogenes in lambs.

Large numbers of orally inoculated thiaminase type 1-producing Clostridium sporogenes failed to establish in the alimentary tract of two conventionally born lambs. Conversely, when similar inoculations were given to two gnotobiotic lambs, large populations of Cl sporogenes established in their rumens and correspondingly high levels of thiaminase were produced. No clinical symptoms of thiamine deficiency or cerebrocortical necrosis were seen despite the presence of high levels of thiaminase in the rumen of one of the gnotobiotic lambs for a period of 86 days.