Cerebral-cortical Necrosis (CCN) or POLIOENCEPHALMALACIA:
Polioencephalomalacia, thiamine deficiency, or PEM is a neurological problem seen in ruminants that is due to a lack of thiamine (B1) to the brain resulting in brain swelling and pressure necrosis of brain tissue.  Caused most often by diet changes that alter gut flora populations so that the new gut bugs produce a thiaminase that deactivates the dietary thiamine. Thiamine is indispensable for the vital functioning of the brain...if thiamine is unavailable or its required level is decreased, the brain cortex degenerates.  http://www.saanendoah.com/basicme3.html

Copper Deficiency A Possible Cause of Polioencephalomalacia In Young Goats
S. Copeland
Prairie Diagnostic Services -  Canada