A county board of education may approve the attendance of any or all service personnel at educational conventions, conferences, or school service meetings of service personnel on school days when in the judgment of the superintendent it is necessary or desirable. Attendance at such meetings may be substituted for an equal amount of employment and service personnel so attending shall not suffer loss of pay. Further, the board is authorized to pay all or any part of expenses of any personnel whom it may designate to represent the board at any such educational conventions, conferences or school service meetings or in visitation to another school system.