Heavy rain and cold temperatures in the past fortnight have all but wiped out the early-grazing gains made by farmers in February and March.
Poor grass growth and waterlogged fields have forced farmers to feed silage and increase meal feeding to compensate.
The move back to supplementary feeding is set to negate the financial benefits of mild weather and grass growth.
In the west, poor grass growth has forced dairy farmers to house cows by night and move replacement dairy heifers indoors full time, according to Teagasc specialist Pat Clarke.
Up to 6kg/hd/day of concentrate feed is being fed by some farmers, while the overhang of winter silage stocks is now being put to use.
In the southeast, dairy farmers are feeding up to 5kg/hd/day of concentrate, according to expert George Ramsbottom.
Kerry-based agri-consultant Eddie McQuinn said ground conditions in the southwest were also atrocious.
Mr McQuinn said most farmers had stock housed again and were reporting an increased incidence of grass tetany.
Teagasc has urged farmers to make sure cows are not underfed at this time.
It has also advised maintaining rotation length at 21-23 days, or to graze no more than 4-5pc of the available grazing area on a daily basis.