Evan Williams has been sentenced to three years in prison at Cardiff Crown Court following his conviction last month for causing grievous bodily harm with intent.
He was found to have repeatedly struck 72-year-old Martin Dandridge with a hockey stick, inflicting injuries that included a fractured arm.
The defendant denied the charge but was convicted by a unanimous verdict from the jury after 90 minutes of deliberations.
His wife Cath took over the training licence, saddling Ask Brewster to win the Rosconn Group Fulke Walwyn Kim Muir at Cheltenham.
Recorder Angharad Price said on sentencing on Tuesday morning: “This is an appalling offence. You had a choice that night, you could have waited and let the police deal with the situation but instead you urgently raced to the paddock to deal with it yourself. It is never acceptable to take the law into your own hands.
"This sentence will be a lesson to you that it is always better to call the police if you think a crime is being committed."
Evan Williams was one of the most successful trainers in Wales in recent years, sending out Secret Reprieve to win the 2020 Welsh National
A BHA spokesperson said: “We are aware of the sentencing today of Evan Williams, following his conviction last month. As has been the case throughout this process, we will be in contact with Cath Williams and her staff in the coming days and weeks to provide support as they consider the next steps for their yard.”