Operators of all public livestock markets shall keep on file an accurate record of the date on which a consignment of animals was received and sold, together with the name and address of the buyer and seller, the number and species of the animals received and sold, and the marks and brands on each animal. Said records together with the gross selling prices, commission, and other proper care, handling, and sale charges on each consignment shall be available for inspection by the executive officer of the state board of stock inspection commissioners, his deputy, or authorized inspector. All records of sales during preceding months shall be kept readily accessible for immediate examination.