Shackleford registered his 12th winner from his first crop on Friday when Sweet Abigail tallied a three-length maiden score at Hawthorne in her first start on a traditional dirt surface.
The 2-year-old filly is owned by Mellon Patch Inc. and was bred in Kentucky by Doug and Felicia Branham. Sweet Abigail's dam Impersonate is a sister to three stakes winner, including the multiple graded winner It's No Joke.
Following his 2016 season when he was bred to 138 mares, Shackleford's 2017 stud fee at Darby Dan was recently announced at $15,000, stands and nurses.