Mo. Rev. Stat. § 270.020: When notice not necessary.

If it shall appear and be proven on trial that the owner or owners of such domestic animals, as set forth in section 270.010, shall have actual notice that his or their said animals or stock were restrained, and by whom, and that the parties interested could not agree on the amount of damages demanded, then the three days' notice in writing as required by section 270.010 shall not be necessary to a recovery.