In accordance with the rules, the sheriff may lay off an employee whenever he deems it necessary by reason of shortage of work or funds, the reinstatement of an employee returning from authorized leave, or the abolition of a position or other material change in duties or organization. The seniority and service ratings of employees shall be considered, in such manner as the rules shall provide, among the factors in determining the order of layoffs. The sheriff shall give written notice to the civil service board of every proposed layoff a reasonable time before the effective date thereof, and the civil service board shall make such orders relating thereto as it considers necessary to secure compliance with the rules. The name of every regular employee so laid off shall be placed at the head of the appropriate reemployment list.