There were four new cases of BSE this week, the Department of Agriculture and Food reported yesterday.
These brought the total number of cases so far this year to 51 cases.
This compares with 73 cases for the same period in 2003 and with 123 cases for the same period in 2002.
The diseased animals were found in three dairy herds in Cavan, Cork and Clare and in a beef herd in Co Tipperary.
The beef animal was the oldest victim at 15. The Cavan and Clare dairy cows were eight and the Cork dairy cow was 11.
The latest cases were identified using both traditional passive surveillance and the active surveillance programme.
Under the active surveillance programme, testing of a proportion of fallen stock and cattle destined for human consumption was initiated in July 2000.
This was extended in January 2001 to test all cattle over 30 months destined for human consumption and all casualty animals.
Since July 2001 all fallen cattle are also tested.
Over 2.05 million tests have been carried out up to the end of 2003 under the active surveillance programme (over 662,000 in 2001; over 688,000 in 2002 and over 700,000 in 2003). In addition over 97,000 tests were carried out in January and February 2004.
The Department repeated its weekly statement that the underlying trend remains positive and the increasing age profile of animals confirmed with the disease indicated that the enhanced controls of animal feed introduced in 1996 and early 1997 were proving effective.