A change in diet has rejuvenated expensive entire Lighthorseman who is now on a path to Group racing glory.Trainer Gary Portelli is eyeing off the Group Three Southern Cross Stakes (1200m) at Randwick next month.Portelli said he would nominate the horse for an 1100 metre race at Rosehill on Saturday and if he performed well in that he would give him a shot at Group company.Lighthorseman scored a dominant victory at Randwick on New Year's Day, much to the relief of his trainer.A $900,000 yearling

A change in diet has rejuvenated expensive entire Lighthorseman who is now on a path to Group racing glory.

Trainer Gary Portelli is eyeing off the Group Three Southern Cross Stakes (1200m) at Randwick next month.

Portelli said he would nominate the horse for an 1100 metre race at Rosehill on Saturday and if he performed well in that he would give him a shot at Group company.

Lighthorseman scored a dominant victory at Randwick on New Year's Day, much to the relief of his trainer.

A $900,000 yearling, Lighthorseman is the most expensive horse Portelli has trained and the most challenging.

His career has been restricted to just six starts, due mainly to a throat operation which sidelined him for a lengthy period.

Lighthorseman's only other win came at Hawkesbury in a maiden almost a year ago.

Two starts ago Lighthorseman bucked shortly after the start of a race at Randwick, dislodging jockey Nathan Berry, and he was ordered back to the barrier trials.

"He just wasn't a happy horse and started dogging it, he just didn't want to do it anymore," Portelli said.

"Even though he looked well he still had this discharge and mucus up his nose and he was always irritated, he just wasn't a happy horse.

"If I'd have won the Magic Millions I don't think I would have been as relieved as I was when he won at Randwick the other day."

Since the throat operation Portelli said feeding the four-year-old had been a work in progress, until now.

"We changed his whole diet and the horse has changed his whole demeanour. It's only in the last month we've worked his feed out," he said.

"Everyone's been trying to ring me to find out what it is but I told them it's a secret.

"His airway is so open that he can actually get feed particles down into his airway. So it's like every time you eat, the food is going down the wrong hole.

"That's what we've been having trouble with so I've had to modify his feed and we've come up with a way of feeding him that stops that happening."

Now Lighthorseman is a happy horse and it's showing.

"He's back to winning gallops and smashing them in trackwork instead of going up to them, putting his head in front and putting the brakes on," Portelli said.

Portelli believes the run at Rosehill will have Lighthorseman primed for the step up to Group level.

"He'd be taking on some pretty handy horses but I would be banking on him having a fitness edge," Portelli said.