Blood thiamin concentrations in bovine polioencephalomalacia.

Thiamin concentrations were determined by the thiochrome method in blood from 16 cattle with polioencephalomalacia (PEM) or other apparent central nervous disorders. The mean blood total thiamin concentration of the five cattle with PEM (20.5 +/- 5.1 microg/100 ml blood) was not significantly different from concentrations in the cattle with the other disorders, despite evidence of a thiamin diphosphate deficiency reported in cattle with PEM.