Despite its name, Absolutely Win never actually finished first in 17 starts.

The gelding's last race, in July 2017, was no different.

He finished ninth — one final disappointment for the four-year-old, who once sold for $180,000 but ended up at the abattoir.

Absolutely Win's death was highlighted as part of an investigation aired by the ABC's 7.30 program, into the widespread slaughter of racehorses for pet food and human consumption at abattoirs and knackeries in NSW and Queensland.

The horse was most recently bought for racing in 2017 by Killara Thoroughbreds — one of the biggest owners of racehorses in Queensland.

They paid $500, but Absolutely Win had sold for as much as $180,000 in 2014 before its career took a slide.

Absolutely Win's career prize money totalled $22,400.

Queensland trainer Ben Robinson prepared the horse for its final race.

"He wasn't going to be a fast enough horse for us to keep as a trainer," Mr Robinson said.

"My understanding is that the horse was sold by the owners for pleasure riding.

"My job was to prepare the horse to race, I didn't actually own it."

Meramist Abattoir is under investigation for alleged animal cruelty. ( ABC News )

Killing thoroughbreds, while not illegal, is at odds with Racing Queensland's Animal Welfare Strategy to "minimise the 'wastage' of racing animals".

Yesterday morning, the Queensland Government ordered biosecurity officers to investigate the animal cruelty allegations at Meramist, the abattoir at which Absolutely Win was killed.

Absolutely Win was slaughtered there in the past 18 months but a Killara Thoroughbreds spokesman said the gelding was sold two years ago as "a riding horse".

He said Killara Thoroughbreds could have up to 90 horses in its care at any one time.

"He was a big bay horse, we had it about six or eight weeks," he said.

"It's been over two years and it would have been one we've sold as a riding horse.

"It was about 400 horses ago."

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Watch Duration: 7 minutes 59 seconds 7 m Champion horse trainer Chris Waller was "schocked" after seeing one of his horses in the abattoir footage.

'We hope they stay in good homes'

Owning racehorses is a pricey pursuit, and the fees horse trainers charge can vary significantly.

Connections should expect to pay at least $350 a week as a base rate when their horse is racing, but the bill for a more prominent trainer is often upwards of $500.

And while that price includes food, it does not cover costs like vet bills.

"It's not hard to find them homes when they're finished racing," the Killara Thoroughbreds spokesperson said.

"They go to equestrian, polo or polocrosse, and a big percentage of mares end up as surrogate mothers, things like that.

"We supplied about 40 horses for the movie The Cup, and they ended up buying those.

"I have no doubt that we might rehome some and then they end up at the meatworks.

"We can only hope that they stay in good homes."