Well high nitrogen usage depresses clover as it affects the nitrogen fixation nodules, and conversely phosphate greatly encourages clover growth. So in future I would just apply a nitrogen fertiliser, or N + K, but no P.
In the meantime, the only way for instant removal is to add a selective herbicide like 2-4,D which is not poisonous to livestock as it is a plant hormone, not toxic to animals, so you can carry on grazing it after application. (If they don't mind the taste.)
Or borrow someone else's stock to eat out the clover. (I can bring a tame cow and calf along!)