It is advised to keep cattle, horses and sheep or other livestock out of fields and pastures until granules or prills have fully dissolved and are no longer visible.  If sufficient moisture is present fertilizer granules or prills will typically dissolve in 3 -4 days, often much sooner, but under dry conditions relying on soil moisture and dew this can take longer.  Any spillages especially near gateways or where refilling the spreader could represent a particular risk and should always be cleared up to avoid direct ingestion.