Four cases of BSE have been confirmed in the past week resulting from tests on herds in Cos Cork, Kilkenny, Galway and Meath.
The tests, which were carried out at the State Laboratory, confirmed the presence of BSE in cows born in 1995, 1993 and 1996.
Three of the cows were tested as a matter of procedure because of their age while the fourth was checked out after a farmer became worried about the symptoms the animal was displaying and contacted a vet.
The four separate herds are to be depopulated, and compensation for all the animals is set to be paid to the farmers by the State, a spokesman for the Department of Agriculture confirmed.
This is the standard practice under the BSE surveillance programme, which has been in operation in Ireland since July 2000. The suspect animal is euthanised and a sample of the brain is sent for testing to the State Laboratory in Abbotstown, Co Dublin. Once infection is confirmed, the rest of the herd is slaughtered.
The total number of BSE cases so far this year stands at 236.