So what has gone wrong? The cannibal feed given to cows was only effectively banned in 1996. We eat cows at 30 months old, so the government argument is that this beef will not carry BSE, since it was born after the feed ban. But in 1999 more than 2,000 cows went down with BSE, and it is known from statistical analysis that 14,000 have BSE but are not showing symptoms as yet.
The rate of decrease of disease in the national herd is thought by epidemiologists to be too low for the feed to be the only cause of BSE, bearing in mind the partial feed ban of 1988. So some of the herd looks as though it has endemic BSE.
Medical statisticians will know for sure in 2001, when BSE should not show in further animals born in 1996. If there is BSE then, a grim situation arises because we will know for sure the disease is permanent.