9 C.F.R. § 72.6
Cattle in quarantined areas where tick eradication is not being conducted may be shipped or transported interstate in accordance with §§ 72.9 through 72.15 under the following conditions: The cattle must have been dipped twice with a permitted dip as provided in § 72.13 , with an interval of 7 to 12 days between dippings immediately preceding shipment, at a designated dipping station approved under § 72.16 and located in the State of origin of the shipment or, in specific cases, after having been otherwise treated at a designated dipping station under the supervision of an APHIS inspector and in a manner approved by the Administrator. In all cases, the cattle must be inspected by an APHIS inspector just prior to final dipping, found to be apparently free of ticks, and be certified as such by APHIS before the cattle may be released for interstate movement.
9 C.F.R. §72.6