The state veterinarian, deputy state veterinarians and livestock inspectors, shall receive salaries fixed by the state director of agriculture and necessary traveling expenses in the discharge of official duties, payable out of the funds provided for the maintenance of the veterinary service. The state veterinarian, deputies and livestock inspectors shall each render an itemized account to the said director of agriculture of all the traveling and incidental expenses incurred in working under this law. Said account or accounts shall be audited, and if found correct, shall be allowed as is now or may hereafter be provided by law.