The decision comes after an internal review following Dairy Crest's acquisition of the St Ivel spread brands last November. JAA was the incumbent on Dairy Crest, while OMD UK handled media for the St Ivel brands.
Dairy Crest's consolidation means that JAA adds the Utterly Butterly, St Ivel Gold, Vitalite and Carapelli brands to its portfolio. Its existing Dairy Crest brands include Clover, Argento, Willow and Frijj milkshake.
The dairy company is expected to spend £10 million annually following JAA's appointment. The agency will work on the consolidated business from 1 April.
St Ivel focused its spend in 2002 on Utterly Butterly with £3.5 million of above-the-line support. The media consolidation comes as Dairy Crest nears the completion of a creative review with Grey Worldwide and Banks Hoggins O'Shea/FCB. Grey is the Dairy Crest incumbent while Abbott Mead Vickers BBDO handles St Ivel.
Dairy Crest activity in the past year has included advertising to support the launch of its olive oil spread Argento and Frijj's sponsorship of the ITV ratings failure Elimidate.
Rob Stephens, the deputy managing director at JAA, said: "The St Ivel brands opportunity is exciting in itself, endorsing the contribution we've made to the existing Dairy Crest business. We are also very pleased to have won such substantial incremental blue-chip business after an objective review against tough opposition."
Dairy Crest paid £86.5 million for the spreads business of St Ivel. The business was acquired from Uniq Group.