Donegal edged slightly ahead of the Dawn Meat plant at Ballyhaunis, Co Mayo where almost 31% of bullocks killed were graded R3. Moyvalley Meats (Bergins) at Broadford, Co Kildare and Exel Meats at Kilbeggan were both on 25% of the kill.
Dawn Meats at Ballaghadereen were on 24%, the Kepak plant at Clonee, Co Meath on 23% and Slaney Meats at Bunclody, Co Wexford and AIBP at Clones, Co Monaghan both at 22%.
Almost 14% of the bullocks killed at Donegal Meats were U3 grade, almost four times the national average of 3.6% and more than double nearest rivals, Dawn Meats at Ballaghadereen, with 6.5%.
Exel Meats, Kilbeggan recorded just under 6% U3 animals, marginally ahead of Slaney Meats and AIBP Clones, both over 5%.
The highest percentage of O3 grade bullocks were slaughtered at Jennings of Ballinrobe at 39%, a whisker ahead of Kepak, Watergrasshill at 38.9%.
There was 35% of the kill at Charleville Foods - owned by the Dawn Group - classified O3 and almost 34% at AIBP in Cahir, Co Tipperary.
Dawn Meats at Midleton had 32%, Ashbourne Meats, Roscreea 31.8% and AIBP, Bandon 30.5%. The national average for O3 bullocks was 23.6%.
Overall, the kill for the six month period returned 7.6% U grade - across at fat scores - a total of 43.8% R grade and 41.8% of the kill O grade.
This was the first half year of grading being carried out by the newly installed mechanical grading machines, which have replaced the manual system at the factories since last Autumn.