Cal. Code Regs. tit. 4 § 1864
No veterinarian or vendor shall dispense, sell or furnish any feed supplement, tonic, veterinary preparation, medication, or any substance containing a prohibited drug to any person within the inclosure unless there is a label specifying the name of the dispensing veterinarian, the name of the horse or the purpose for which the said preparation or medication is dispensed, and the name of the person to which dispensed, or is otherwise labelled as required by law. Any substance containing a prohibited drug shall be labelled, "Caution. Contains Prohibited Drug. Not to be used on race day."
Any alteration to the sex of a horse from the sex as recorded on the certificate of foal registration or the eligibility certificate or other official registration certificate of the horse shall be reported to the racing secretary and the official horse identifier if the horse is entered to race at any race meeting.
Cal. Code Regs. Tit. 4, § 1864