THE four new cases of BSE confirmed last night by the Department of Agriculture brings the total to 54 so far this year, the highest on record since 1989.
The new cases have been found in herds in Co Cork - which has the highest infection rate in the Republic - and in Cos Galway, Meath and Tipperary.
The Cork case was in a six-year-old Friesian cow from a dairy herd of 48 animals and the Galway case was in a five-year-old Simmenthal animal in a suckler herd of 90 animals.
The new Tipperary case is also in a six-year-old cow from a suckler herd of 74 animals and the Meath case was found in a seven-year-old cow from a dairy herd of 34 animals.
All the animals involved in this latest round of cases will be destroyed and investigations have already started into what other herds the animals may have come from and what they have been fed.
Experts believe the rising number of cases in the Irish, national herd may be related to continuing use of contaminated animal feed made from meat and bonemeal.
Strict new regulations have been put in place in an attempt to prevent any more cases of the disease in the national herd off seven million animals.
Since 1989, there have been 169 cases of the disease in the Republic; 5,000 in Northern Ireland; and nearly 170,000 in Britain.
Figures given to a meeting of EU farm ministers early this week show that 278,220 calves and more than 900,000 animals over 30 months old have been slaughtered in Britain under the EU eradication scheme. Britain is hoping to have the EU beef and beef product export ban lifted.