Federal Register dates can hide the FDA approval date

When dating a US animal-drug claim, the Federal Register publication and effective date can differ from the approval date: one 1997 notice states the supplement was approved as of a date in December 1996. Read the 'approved as of' sentence or the FOI summary cover, not the notice date. FOI summary IDs on animaldrugsatfda downloadFoi are not grouped by application, and an older supplement can sit far outside a scanned ID range, so a web search on the NADA number can find what a range scan misses.