Glanbia, the State's largest dairy group, implemented an average rise of 7 per cent rise in the wholesale price of the milk yesterday. The group, which claims half the national market and a 70 per cent share in Dublin, postponed the rise a month ago. This followed a telephone call between its managing director, Mr Ned Sullivan, and the Taoiseach, Mr Ahern, after the Government expressed concern about the possible inflationary impact of the move. Glanbia claimed the rise reflected its rising cost structure and sales volumes to retailers.