BSE has been discovered in another three year old animal - the second case in the past few weeks involving an animal born in 1999.
The Department of Agriculture say a full investigation is underway to establish if there is any link beween the two cases.
For several years, the beef sector was able to reassure consumers at home and abroad that no case of BSE was found here in an animal born after 1996 , when controls on cattle feeds were tightened up.
But so far this year, BSE was found in four animals born in 1997. And only three weeks ago, it was discovered in a bull born in 1999 in Co Limerick.
Now a friesian cow in County Kerry has been identified with the disease. It was 46 months old, also born in 1999.
The Kerry animal was discovered after it showed clinical signs on the farm.
The Department of Agriculture say both 1999 cases were located within 20 miles of each other and were born within a week of one another.
The Department also say that the manner of detection of the 1999 cases indicates that the Departments multi-layered controls are effective in protecting consumers.
The current year is the worst on record here for BSE with 333 cases - 87 more than last year.
But in the second half of this year there has been a 32% fall-off on 2001 - with 57 fewer cases.
