§ Dr. Lynne JonesTo ask the Minister of Agriculture, Fisheries and Food what assessment he has made of the studies on the presence of the BSE infective agent in cattle(a) under 30 months of age and (b) older than 30 months. [119036]
141W
§ Ms QuinBetween January and March 1999, brain tissue was collected from approximately 4,163 randomly selected cattle, over five-years-old, passing through the Over Thirty Month Scheme (OTMS) and examined for the presence of BSE infection. The purpose of the study was to assess if cattle carry any detectable BSE infection before clinical symptoms are seen.
Of the brains removed, a total of 3,951 were in a suitable condition for examination and initial results showed that 18 cattle had signs of BSE infection. The remaining 3,933 were negative and showed no signs of infection. Taken in isolation these results could indicate that approximately 0.5 per cent. of the remaining cattle over five years and older may be infected. It will not be possible fully to interpret the data until the results from other diagnostic tests and a statistical analysis of the age structure of cattle slaughtered under the OTM Scheme is complete.
A similar study of cattle under thirty months of age has not been undertaken because it would be very unlikely that brain pathology would have developed in such young animals if they were infected. In experimental conditions when calves were orally challenged with relatively high doses of BSE infected cattle brain, the first stage at which signs of BSE infection could be detected in the brains of these challenged cattle was at 32 months after dosing. No signs were seen prior to this at 26 months post challenge.