Another young BSE-infected cow born after the animal-feed controls in the State were thought to have been fail-safe has been found.
The animal was born in 1998 and was identified last week as having the disease. The animal came from a dairy herd in Co Cavan.
This is the fourth case found in younger animals since the beginning of the year - two born in 1998 and two in 1997.
There have been 73 cases of BSE identified so far this year, compared with 107 in the same period last year.
The vast majority of the infections have been found in older animals, born before late 1996, when the segregation of cattle rations from pig and poultry feed was ordered by the EU.
Before that, poultry and pigs were allowed consume meat-and-bone meal. It was not known was that tiny amounts of contaminated meat-and-bone meal could cause a cycle of the disease and contamination of cattle feed.
The EU ordered the separation of systems involved in providing feed and this has contributed dramatically to the fall in the number of animals born with the disease.
However, scientists have warned that isolated cases of BSE would still appear in animals born after 1997.
There have been suggestions that calves may have been fed on poultry rations on some occasions up to 2000, when the EU banned the use of meat-and-bone meal in pig and poultry rations.