A jockey shall weigh in after the finish of the race and he shall not weigh less than one pound of his proper weight nor two pounds over his proper weight except that the stewards may take into account any excess weight caused by rain or mud. The stewards may disqualify any horse whose jockey weighs in at less than one pound of his proper weight, and shall discipline the persons responsible therefor.
Cal. Code Regs. Tit. 4, § 1701