29 CFR § 780.602 - General explanatory statement.

Ordinarily, as discussed in subparts D and E of this part 780, an employee who in the same workweek engages in work which is exempt as agriculture under section 13(a)(6) or 13(b)(12) of the Act and also performs nonexempt work to which the Act applies is not exempt in that week (§ 780.11). Employees of a farmer are not employed in work exempt as “agriculture” while engaged in livestock auction operations in which the livestock offered at auction includes livestock raised by other farmers (Mitchell v. Hunt, 263 F. 2d 913) (C.A. 5); Hearnsberger v. Gillespie, 435 F. 2d 926 (C.A. 8). However, under section 13(b)(13) an employee who is employed by a farmer in agriculture as well as in livestock auction operations in the same workweek will not lose the overtime exemption for that workweek, if certain conditions are met. These conditions and their meaning and application are discussed in this subpart.