(Reuters) - The world's largest dairy exporter Fonterra on Thursday cut its milk collection forecast for fiscal 2020, citing adverse weather conditions in several parts of New Zealand.The company lowered its expectation for the 2020 season to 1,515 million kilograms of milk solids (kgMS) from the prior forecast of 1,530 million kgMS.It maintained its full-year adjusted earnings guidance and farmgate milk price range.