Technology will make labeling battles moot. Labeling is back in the news because of one mad cow. Actually, the Canadian Holstein seems to have been pretty well labeled. Investigators were able to use her paper trail to trace her north of the border and then confirm it by testing her DNA. Instead of slaughtering 450 calves in order to kill the mad one's progeny, they could have DNA testing to fin the calf—probably still too expensive. In any case, Washington state's single mad cow is now propelling the usual gaggle of "consumer advocates" to push Congress to adopt new labeling...