Except in those counties in which the board of supervisors has by ordinance fixed a different schedule of dates or pay periods for the payment of salaries of the officers, deputies, clerks and employees of the several departments and institutions of the county government, as authorized in Section 28003, the auditor shall, on the first day of each month, or the first day following the specified pay period draw his warrant upon the treasurer in favor of each officer, deputy, clerk, and employee for the amount of salary due him for the preceding month or pay period.