A decade ago, many cows on farms throughout the United Kingdom began to fall ill. Worried owners watched as the disoriented animals staggered about, lowing pitifully, and eventually died. Veterinarians recognized the symptoms as similar to those of scrapie, a communicable brain disease that attacks sheep. The cattle had become infected, it was thought, when they ate feed that had been fortified with sheep offal—brains, spinal cords, and other organs. Though the practice of adding offal to feed was banned in 1989, the epidemic of mad cow disease continued into the 1990s and peaked in 1992 at 37,000 new cases.
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