A steer escaped and led handlers on a merry chase through the grounds of WA Parliament House during an event promoting mental health awareness.

The steer called Winston and a heifer called Clementine were brought in as part of an event for R U OK? Day.

But witnesses said Winston hoofed it as he was being awarded a ribbon during a parade in front of the parliament.

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He lapped Parliament House with his handler and a pack of excited Perth camera operators in tow.

The handler eventually corralled Winston and led him back to the waiting press conference and politicians.

His partner in crime, Clementine, wasn't really on her best behaviour either, peeing all over the place when she was led up to the microphones for her chance in the spotlight.

Always quick off the mark, Regional Affairs Minister Alannah MacTiernan remarked "that cow's pissing it in".

The cow and steer are being donated for sale at this year's Perth Royal show by Dardanup farmer Peter Milton, with funds donated to Black Dog Ride.

"It was Winston's first day out of the shed in three months, his first public appearance. I guess he got a bit embarrassed, Mr Milton said.

"He will be on his best behaviour, the sting's taken out of him now."

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Winston is due to appear at a BBQ at Mandurah tomorrow, with Mr Milton assuring people he would get to leave in one piece.

"[It'll be] lamb and goat, we don't want to see his relatives," Ms MacTiernan added.

"I'm really pleased that Winston behaved just as we were hoping he would and created a bit of excitement for the media. That's a well trained piece of cattle."

Meanwhile, some of those at Parliament House said they did not need the bovine duo to contribute any extra fertiliser because it was full enough.

"Usually more bull less cow around here," Margaret Quirk quipped on Twitter.

Mr Milton said while it wasn't planned, the excitement and attention from Winston's antics were welcome if they helped raise awareness about mental health.

The steer will attend other events before his auction, including at supermarkets and at Wave Rock near Hyden, south-east of Perth.

"We've found the steer is a great way to open the door, to get people to talk about mental health," Mr Milton said.