The enormous burial craters for some of the 469,000 cattle casualties of the foot and mouth crisis may cause increased incidence of BSE, according to the government's scientific advisors.  Professor Peter Smith, chairman of the Spongiform Encephalopathy Advisory Committee (SEAC) warned yesterday that among those slaughtered because of the foot and mouth cull are many animals over the age of five years, which are at increased risk of harbouring BSE. Burying these animals could spread the infection through the soil in the countryside, and into the ground water.