As the number of cases of BSE so far this year reached the total for the whole of last year, the Department of Agriculture said one of the new cases was born after the ban on feeding meat and bonemeal to cattle became operative. A cow born into a Limerick herd in 1997 is the third such case to be discovered this year and, according to a Department spokesman, is unlikely to be the last.
"We have to accept that even after the final controls were put into place that there would have been some contaminated food left over on farms and that is the most likely cause of this case," he said.
In 1996-97, the compounding of cattle feed was segregated from feed being prepared for pigs and poultry, which included meat and bonemeal.
British scientists discovered contamination of cattle feed had continued at mills and compounders where feeding stuff was being prepared by the same equipment.
Until then they had not realised that very small amounts of contaminated meat and bonemeal, banned from cattle and sheep feed since 1989, had been entering the cattle feed chain in the compounding and milling process.
The spokesman said that while this year's total had risen to 246, the same number of cases as had been recorded in the whole of 2001, the majority of those had been found in so-called "fallen" animals at knackeries which were not bound for human consumption.
"So far this year, 140 of the cases have been found in this way, in the active surveillance programme, which means that a lot more testing of animals has been going on," he said.
He said three of this year's cases had been found in "casualty animals" and a further 24 had been discovered at meat plants where all animals over 24 months are tested for the disease.
"The percentage of cases found in fallen animals this year has now risen to 57 per cent of the total and so far this year we have carried out 59,000 tests on these animals," he said. "Overall, the age profile of the cases we are uncovering is increasing but it is possible we will discover more cases born after 1997."
He said one encouraging factor this year was the August/September totals: they amounted to 21 and 14 respectively, well down on last year's monthly equivalent of 41 and 33.