The rise of incidents of bovine spongiform encephalopathy (BSE) or "mad cow disease" since the late 20th century will likely further diminish the remaining appeal of this curious regional dish. Brains from cows over 30 months old at slaughter are no longer permitted in human food in the United States (Hefling, 2004). Some restaurants have taken to serving pigs' brains instead of cow brains due to BSE concerns. But as pigs' brains are substantially smaller than cows' brains, the amount of preparation required for each sandwich increases. Each brain must be cleaned before being sliced and pigs' brains produce fewer slices. Pig's brains are also much higher in cholesterol at over 1,000 mg per ounce.