POLIOENCEPHALOMALACIA

Polioencephalomalacia (PEM) is a neuropathologic condition of ruminant s that can be induced by a variety of neural metabolic disruptions. Th ese include altered thiamine status, water deprivation-sodium ion toxi cosis, lead poisoning, and high sulfur intake. Investigations of sulfu r-related PEM have demonstrated that the onset of the clinical signs c oincides with excessive ruminal sulfide production. A number of rumina l factors could modulate the production and absorption of ruminal sulf ide. The development of a convenient method to estimate ruminal gas ca p H2S has made it possible to identify cattle with high levels of rumi nal H2S and evaluate their risk of developing PEM.