The chairs of Lakeland Dairies and Dairygold have warned that milk processing plants could have to shut down if the nitrates derogation is lost and farmers have to revert to a maximum stocking rate of 170kg organic N/ha. “If, for talk sake, it went to 170[kg], milk supply fell off; close plants - that’s not a decision anyone wants to make,” Niall Matthews of Lakeland Dairies said.