In addition to the assessment authorized pursuant to RCW
16.67.120, the commission has the authority to collect an additional assessment of fifty cents per head for cattle subject to assessment by federal order for the purpose of providing funds for a national beef promotion and research program. The manner in which this assessment will be levied and collected shall be established by rule. The authority to collect this assessment shall be contingent upon the implementation of federal legislation providing for a national beef promotion and research program and the establishment of the assessment requirement to fund its activities.