John Meagher has guided the careers of some of racing's elite riders and Ash Butler hopes to one day be counted among them.

Melbourne Cup winning jockeys Brett Prebble and Steven King were apprenticed to Meagher when he was a leading trainer at Flemington.

Twenty-year-old apprentice Butler joined the Meagher Racing team a week ago and the combination achieved its first success when Rose Of Kentucky won Wednesday's Glenlogan Park Stud Handicap (1200m) at Doomben.

Butler believes working closely with Meagher on a daily basis will benefit his riding career.

"Everyone knows how good John Meagher is with apprentices so it's a big step up for me but one that I'm enjoying," Butler said.

"I've only been with the Meagher team for a week and this is my first winner for them."

Butler has ridden 21 city winners and has just under a year left before his apprenticeship ends.

Meagher was quick to praise Butler's work ethic after Rose Of Kentucky's win.

"He's positive, he's on the ball and he listens to us," Meagher said.

Rose Of Kentucky, a half-sister to VRC Oaks winner Samantha Miss, enhanced her broodmare value by winning at Doomben but Meagher believes she can continue to improve as she steps up in journey.

"I'm confident she'll get a mile-and-a-quarter (2000m) without too much trouble and she's quite a useful mare," he said.

"If you look at her form you'd wonder how on earth she could win but she's a nice mare and we've got her going well."

Meanwhile the perils of venting on social media have cost jockey Ric McMahon $750.

Racing Queensland stewards charged McMahon for misconduct and fined him after he posted "insulting and abusive comments" towards trackwork rider Katie Barr on Facebook last week.

In issuing the fine, stewards took into account McMahon's guilty plea and the remorse he showed for his actions.

McMahon will be hoping for a more positive outcome when he rides Better Than Ready in his return to racing at Doomben next Monday.