California Codes, Business and Professions Code - BPC, Division 8 — Special Business Regulations, Chapter 4 — Horse Racing, Article 1 — General Provisions and Definitions, Section 19413.5
“Quarter horse” is any horse (including mare, gelding, colt and filly) that meets the requirements of and is registered by the American Quarter Horse Association.
Notes
Defines a "quarter horse" as any horse, including a mare, gelding, colt, or filly, that meets the requirements of and is registered by the American Quarter Horse Association. The definition requires both satisfaction of that association's requirements and registration, while stating no age, location, monetary threshold, deadline, or exception.
Use as reference
Lexinter.net | California Code, Business and Professions Code - BPC § 19413.5 | https://laws.lexinter.net/codes/california/business-and-professions-code/division-8/chapter-4/article-1/section-19413-5