Group One-winning jockey Katelyn Mallyon has been suspended for 17 days over her handling of a horse in a staying race at Moonee Valley.

Mallyon was charged over her ride on the Gai Waterhouse and Adrian Bott-trained Valediction in a 3000m race at Moonee Valley on February 3.

Valediction became involved in a speed battle with Barge And Charge before both horses weakened to be beaten 53 lengths and 33 lengths respectively.

Barge And Charge's jockey Dean Holland was suspended in March for three weeks after pleading guilty to a charge over his ride, while Mallyon's case had been adjourned until Thursday.

Mallyon was found guilty by the Racing Appeals and Disciplinary Board of not taking all reasonable and permissible measures to ensure her horse had full opportunity to win or finish in the best possible position.

Her 17-day penalty is due to start after Saturday's meeting at Morphettville where she rides Lycurgus in the Group One South Australian Derby and she can return on May 31.