Cerebrocortical necrosis

Polioencephalomalacia (PEM), also referred to as cerebrocortical necrosis (CCN), is a neurological disease seen in ruminants that is caused by multiple factors, one of which is thiamine depletion in the body. Thiamine (vitamin B1) is a key chemical in glucose metabolism that, when deficient, is most threatening to neurological activity. In addition to altered thiamine status, an association with high sulfur intake has been observed as a potential cause of PEM. PEM may also be caused by other toxic or metabolic diseaes such as: acute lead poisoning or salt poisoning. Cattle, sheep, goat, and other ruminants that are diagnosed with PEM or pre-PEM suffer opisthotonus, cortical blindness, disoriented movement, and eventually fatality, if left untreated. Current data shows that the onset of PEM can range from birth to late adulthood.

Source: Wikipedia

(G) Very specific problems