Polioencephalomalacia (PEM) is also referred to as thiamine deficiency, vitamin B1 deficiency, or cerebrocortical necrosis (CCN). It was first reported in ruminants in 1956 in North America. PEM occurs sporadically in cattle and sheep in many parts of the world. Thiamine deficiency is most commonly seen as clinically-affected animals with low thiamine levels upon testing. Dr. Renée Lodder at Bimeda audits the research that exists by looking at subclinical thiamine deficiency in ruminants which may be economically significant.