| Number of Mares Reported Bred to Thoroughbred Stallions in 2021 | |||||
| A B C D E F G H I J K L M N O P Q R S T U V W X Y Z | |||||
| Stallion | Mares Bred | State | |||
| Macho Rocket | 3 | AR | |||
| Maclean's Music | 221 | KY | |||
| Maddy Bird | 6 | OH | |||
| Madefromlucky | 45 | MD | |||
| Magick Dancer | 2 | FL | |||
| Magna Graduate | 3 | OK | |||
| Maimonides | 7 | OK | |||
| Majestic City | 6 | NY | |||
| Majestic Harbor | 22 | CA | |||
| Majestic Hussar | 28 | OK | |||
| Make Music for Me | 3 | OH | |||
| Make Reservations | 2 | NY | |||
| Malahini | 1 | PR | |||
| Malibu Moon | 84 | KY | |||
| Man Law | 3 | ||||
| Man of Faith | 1 | OR | |||
| Man On the Street | 1 | OK | |||
| Mania A. | 2 | PR | |||
| Mank | 9 | AB | |||
| Many Rivers | 6 | CA | |||
| Maraud | 13 | PR | |||
| March Twelth | 1 | MN | |||
| Marine Landing | 4 | AB | |||
| Mark Valeski | 38 | AR | |||
| Marking | 28 | NM | |||
| Marshallofthistown | 1 | UT | |||
| Mass Market | 1 | BC | |||
| Master James | 3 | NY | |||
| Mastery | 94 | KY | |||
| Matanzas Inlet | 2 | FL | |||
| Matt's Broken Vow | 2 | MN | |||
| Matthewsburg | 1 | TX | |||
| Max Forever | 2 | AB | |||
| Maximum Security | 135 | KY | |||
| Maximus Mischief | 171 | KY | |||
| McCraken | 11 | KY | |||
| McKinzie | 214 | KY | |||
| Mean Season | 5 | LA | |||
| Medaglia d'Oro | 111 | KY | |||
| Medal Count | 8 | OH | |||
| Medallist | 4 | PA | |||
| Mendelssohn | 197 | KY | |||
| Mesa Thunder | 2 | CA | |||
| Micromanage | 6 | NY | |||
| Midnight Lute | 72 | KY | |||
| Midnight Storm | 85 | KY | |||
| Midshipman | 102 | KY | |||
| Mineshaft | 41 | KY | |||
| Ministers Wild Cat | 13 | CA | |||
| Miraculousmo | 2 | TX | |||
| Misremembered | 19 | CA | |||
| Mission Impazible | 29 | NY | |||
| Mister Lucky Cat | 8 | OK | |||
| Misty'sgoldentouch | 1 | CA | |||
| Mitole | 208 | KY | |||
| Mizzen Mast | 10 | KY | |||
| Mo for the Money | 28 | AR | |||
| Mo Tom | 21 | LA | |||
| Mo Town | 204 | KY | |||
| Mobil | 12 | OH | |||
| Mohaymen | 40 | KY | |||
| Mondavi | 2 | IN | |||
| Moonshine Mullin | 5 | AR | |||
| Mor Spirit | 100 | KY | |||
| More Than Ready | 121 | KY | |||
| Moro Tap | 17 | TX | |||
| Mosler | 41 | MD | |||
| Most Mischief | 4 | NE | |||
| Mr Speaker | 22 | KY | |||
| Mr. Big | 29 | CA | |||
| Mr. Gold Mover | 4 | NM | |||
| Mr. Money | 79 | FL | |||
| Mr. Monomoy | 17 | NY | |||
| Mr. Prankster | 5 | WV | |||
| Mr. Rancho Vista | 3 | WA | |||
| Mr. Trieste | 5 | NM | |||
| Mr. Z | 3 | KY | |||
| Mrazek | 16 | CA | |||
| Mshawish | 40 | KY | |||
| Mucho Macho Man | 52 | KY | |||
| Mughaadir | 1 | NM | |||
| Munasaaq | 2 | PR | |||
| Munnings | 219 | KY | |||
| Musaiter | 5 | CO | |||
| My Golden Song | 24 | TX | |||
| My Italian Ex | 1 | IA | |||
| My Pal Charlie | 7 | LA | |||