| Omar Tournoud | San Isidro
17-Apr-25,
Simplemente Vida |
| Omar Vargas | Sunray Park
18-Apr-26,
Escarchas Vike |
| Omar Villarreta | San Isidro
24-Oct-24,
Manjar Exquisito |
| Orlando Fernandes | Gavea
29-Oct-24,
Rack Sameah |
| Orlando Guerrero | Turf Paradise
15-Apr-26,
Tell America |
| Orlando Noda | Aqueduct
24-Apr-26,
Sequential |
| Orlando Perez | San Isidro
15-May-25,
Isla Soledad |
| Orlando Rose | Tampa Bay Downs
16-Apr-26,
Zingales King |
| Orlando Vinardi | San Isidro
07-Sep-23,
Buenos Anos |
| Orrin Cogburn | Remington Park
17-Apr-26,
Jet Black Corona |
| Ortega | San Isidro
31-Oct-24,
Land Hopper |
| Ortis Henry | Finger Lakes
26-Nov-24,
Watch Hill |
| Osamu Hirata | Tokyo
26-Apr-26,
Blue Sky Blue |
| Osborne Smith | Charles Town
17-Apr-26,
Mo Joke |
| Oscar A Barrionuevo | Palermo
14-Nov-23,
Nildita |
| Oscar A Farias | Palermo
27-Jun-23,
Maxi Texano |
| Oscar A Galassi | Palermo
19-May-23,
Burlata |
| Oscar A Galli | Palermo
06-Jun-23,
Lucci |
| Oscar A Kalk | Palermo
30-May-23,
Cebreiro |
| Oscar A Rebora | San Isidro
11-Jan-24,
Grand Implosion |
| Oscar A Zavatarelli | Palermo
09-Jun-23,
Flicka Fil |
| Oscar Almada | San Isidro
05-Apr-25,
Mr. Chino |
| Oscar Arredondo | San Isidro
04-May-23,
Hit Del Verano |
| Oscar Barrera III | Aqueduct
13-Apr-26,
Capt Jax Parrow |
| Oscar Blanchet | San Isidro
15-Dec-24,
Mi Amigo Cocho |
| Oscar Cagnoli | San Isidro
06-Jun-24,
Quala De Gusti |
| Oscar Cancela | Palermo
15-Oct-23,
Fix Felix |
| Oscar Carrete | Sunland Park
23-Mar-25,
Perry Legacy |
| Oscar Cincunegui | San Isidro
15-May-25,
Luca Changretta |
| Oscar Constancio | Sam Houston Race Park
30-Apr-23,
Daring Goodtime |
| Oscar Constancio, Jr. | Lone Star Park
19-Oct-25,
Coronaditoo |
| Oscar Conti | San Isidro
10-Apr-25,
Russian Sindar |
| Oscar Corsi | San Isidro
09-Sep-23,
Pequena Victoria |
| Oscar D Lopez | Palermo
26-Jun-23,
Polirun |
| Oscar E Mihura | San Isidro
12-Oct-23,
Julis Bomb |
| Oscar F Conti | Palermo
03-Jul-23,
Million Reasons |
| Oscar F Fravega | Palermo
29-Oct-23,
Inca Music |
| Oscar Flores | Remington Park
14-Dec-25,
Da Candy Cane |
| Oscar Fravega | San Isidro
11-Apr-24,
Jorkina |
| Oscar G G | Hipodromo Chile
02-May-25,
Don't Cry Daddy |
| Oscar G Villarroel | Palermo
27-Jun-23,
A La Cumbre |
| Oscar G. Mancilla | Laurel Park
26-Apr-26,
Manseeyasway |
| Oscar Gonzalez | Gulfstream
27-Jun-25,
Frisson |
| Oscar Heredia | Los Alamitos Racecourse
05-Apr-26,
The Key Is Unity |
| Oscar Hernandez | San Isidro
10-Aug-24,
Lethal Candy |
| Oscar Ibarra | Palermo
24-Jun-24,
Act Now |
| Oscar Kalk | Palermo
17-Oct-23,
Lombada |
| Oscar M M | Valparaiso Sporting Club
14-Nov-23,
Torito De Pucara |
| Oscar M. Gonzalez | Gulfstream
14-Feb-26,
Magic Solar |
| Oscar Mancilla | |
| Oscar Mihura | San Isidro
03-Oct-24,
Porta Venezia |
| Oscar Modica | Fair Grounds
09-Feb-24,
Exacta |
| Oscar Nis | San Isidro
05-Apr-25,
Bearnes |
| Oscar Preciado | Horseshoe Indianapolis
15-Apr-26,
Ap Jessies Cartel |
| Oscar R Ayude | Palermo
10-Nov-23,
Planet Luh |
| Oscar R Boccia | San Isidro
18-Jan-24,
Fantasia Planet |
| Oscar R Cagnoli | Palermo
18-Jun-23,
L'oriental |
| Oscar Rebora | San Isidro
23-Nov-24,
Igual A Daddy |
| Oscar Retegui | San Isidro
25-Nov-24,
Curioso Master |
| Oscar Rodriguez | San Isidro
03-May-25,
Owen Hunt |