Subject to the approval of the department of agriculture of the United States, the inspectors appointed by it, may also be appointed by the said board, for the services set forth in Section 77-4-4 N.M. Stat. Ann., and they shall hold said appointment at the pleasure of said board so long as they remain inspectors of said department and as such are stationed in this state and they shall act as such inspectors without bond or compensation from the state and shall possess all the powers and duties of state inspectors as needed for the purpose of said section.