Someone just posted this to the AzEquine list:

http://groups.yahoo.com/group/AzEquine/message/460

>From: "changarrotours" <changarrotours@...>
>Date: Mon, 26 Apr 2004 18:05:58 -0000
>Subject: [AzEquine] SONORAN HORSE RACES
>
>CHANGARRO TOURS PRESENTS A WEEKEND A OF FUN AND RELAXATION AT SONORA'S
>PREMIER RANCHO LAS BORREGAS. WHILE THERE ENJOY THE EXCITEMENT OF
>MEXICAN HORSE RACING AT EL BELLOTOSO RANCH.ONLY 15 MINUTES FROM THE
>THE NOGALES BORDER. MAY 14,15,&16. CALL 520-548-1658 FOR MORE INFO.

I don't know how good or bad it might be, but thought it sounded interesting.