An extensive ABC investigation has revealed the widespread slaughter of racehorses for pet food and human consumption at abattoirs and knackeries in New South Wales and Queensland.

Key points: Dozens of former racehorses tracked to NSW knackeries to be used in pet food

Dozens of former racehorses tracked to NSW knackeries to be used in pet food Racing NSW rules prohibit racehorses from being sent to abattoirs and knackeries

Racing NSW rules prohibit racehorses from being sent to abattoirs and knackeries One Queensland abattoir was recorded slaughtering around 300 racehorses in just 22 days

WARNING: This story contains images that are distressing

The practice is occurring despite industry rules and animal welfare guarantees.

The undercover investigation revealed disturbing treatment of horses at one abattoir before and during slaughter.

The slaughter of racehorses is not illegal in Australia but it is against Racing NSW policy and rules, which state that all retired racehorses should be rehomed.

Paul McGreevy is a vet and professor of animal behaviour and welfare science at the University of Sydney.

He has been studying thoroughbreds for over 25 years, winning national and international awards for his research.

He is appalled by what he has seen.

"We're talking about destroying animals on an industrial scale," he told the ABC.

"We're seeing animals suffering.

"I don't think anyone in the industry can defend this."

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Meramist Abattoir, Caboolture Qld

Around 300 racehorses were slaughtered at Meramist Abattoir in less than a month. ( ABC News )

For the past two years Elio Celotto and the Coalition for the Protection of Racehorses have been watching the Meramist Abattoir located north of Brisbane.

Using perimeter cameras, they have recorded the daily activities on the ground.

Meramist slaughters mixed livestock, including an estimated 500 horses a month.

"It's an abattoir that kills horses for human consumption," Mr Celotto told 7.30.

"[The meat] goes to various countries in Europe, it goes to Japan, and Russia's a big importer as well."

Elio Celotto and the Coalition for the Protection of Racehorses have been monitoring Meramist Abattoir for two years. ( ABC News )

Separate to the Coalition for the Protection of Racehorses monitoring, a team of undercover investigators has entered the abattoir recording more than a thousand hours of covert vision documenting the horses that have passed through the abattoir and their treatment.

That vision has been provided to the ABC and we've agreed to protect the investigators' identities.

Using the vision recording brandings and the methodical scanning of microchips, the ABC has forensically cross-matched horses slaughtered to the industry's official online record of thoroughbreds, the Australian Stud Book.

Thoroughbreds identified at Meramist in the last 18 months Sunny Fame

Sunny Fame Only Money

Only Money Rapid Feet

Rapid Feet Bumbunga

Bumbunga Valtari

Valtari Moonline Dancer

Moonline Dancer Take A Chance

Take A Chance Vortuka

Vortuka Absolutely Win

The process has revealed around 300 racehorses went through Meramist Abattoir in just 22 days.

They had won combined prizemoney of almost $5 million.

On one day alone, covert cameras record more than 40 racehorses being slaughtered.

"(That) equates to about 4,000 race horses killed in this one abattoir," Mr Celotto said.

The Coalition figures are at odds with the racing industry's data and with Racing Queensland's Animal Welfare Strategy to "minimise the 'wastage' of racing animals".

The Queensland Racing Integrity Commissioner Ross Barnett said that it encourages the racing community and the public to report all animal welfare concerns.

"The Commission works closely with partners including the RSPCA to investigate reports we receive about the treatment of racehorses and Standardbreds whether they are currently racing or retired," he told the ABC in a statement.

The vision obtained by the ABC also shows abattoir workers tormenting animals before they are killed.

The covert cameras record horses being beaten and abused, bolted to the brain repeatedly and ineffectively killed.

Others are kicked and suffer electric shocks while confined in the kill box.

One worker can be seen repeatedly slamming a gate into a group of horses, another beats the horses with a hose.

Professor McGreevy is shocked by the practices.

"That's disgusting," he said, tears welling in his eyes.

"It's absolutely unacceptable that we could let our equine athletes down in this way."

Industry 'wastage'

A branded thoroughbred horse after being slaughtered at Meramist Abattoir. ( ABC News )

Australian horse racing is a big business that requires big breeding.

Last financial year the industry produced 14,000 foals.

Each year, around 8,500 horses are retired from the track.

According to the racing industry less than 1 per cent are ending up at a knackery or an abattoir.

"The industry tells us that 0.4 per cent of horses leaving the racing industry are ending up in a knackery or an abattoir, which I think equates to 34 horses per year," Professor McGreevy said.

"That's what the industry is assuring us of."

But those assurances are unreliable.

"The figures don't add up," he said.

"If my concerns are substantiated, then we're talking about a large number of horses that are meeting a very grisly end."

He said the number of horses disappearing each year could be in the thousands.

"In the order of at least 4,000 horses," he said.

But the national regulator, Racing Australia, introduced a traceability rule three years ago to track the whereabouts of horses from birth to retirement.

The NSW regulator, Racing NSW, told the ABC it is committed to rehoming horses but raised resourcing issues.

"We don't have the resources to get every horse in New South Wales to see if it's alive or passed away."

On Thursday afternoon Racing NSW told 7.30 it would commit to investigating all of the reported horses, but raised questions about jurisdictions.

Both unprofitable and valuable racehorses have ended up slaughtered.

In one instance a horse called War Ends was still listed as being active and racing 18 months after it had been slaughtered at Meramist Abattoir.

In September 2016, in the wake of the greyhound racing scandal involving live baiting and the wastage of unwanted dogs, Racing NSW chief Peter V'Landys announced a thoroughbred horse welfare fund.

"We're going to ensure that every horse in NSW, domiciled in NSW, will be rehomed," Mr V'Landys promised.

Racing NSW, along with Racing ACT, also introduced a new and enforceable rule that, in the event that owners were unable to find a home for a horse that was being retired, prohibited the horse being directly, or indirectly, sent to an abattoir or knackery.

It also stipulated that a horse could not be sold or gifted at a livestock auction not approved by the regulator.

Racing NSW also prohibits horses bred and domiciled in the state being transported intestate for slaughter.

Other states have rehoming policies but have not banned the disposal of thoroughbreds at slaughterhouses.

There are no laws in Australia that make it illegal for abattoirs and knackeries to slaughter horses.

Industry assurances

Peter V'Landys promises that people who break Racing NSW's rules will pay the penalty. ( ABC News )

Mr V'Landys told the ABC that he was unaware of any NSW racehorses ending up at an abattoir or a knackery.

"Because it's against the rules of racing," he insisted.

"We have relationships with some of the knackeries and they tell us, you know, they tell us if there's a thoroughbred that comes in.

"And they've been very cooperative because they know what the rule is."

He told the ABC that anyone who is found to be breaking the rules will be dealt with severely.

"Without divulging all our secrets, we have intelligence networks that we can trace if horses are being sent to those. And we have cooperation from various people to know if this if that is occurring." Mr V'Landys said.

"If it's happening, we will put the full force of the law against them because they are breaking the rules of racing."

Luddenham Pet Meat, Luddenham, NSW

A number of racehorses were recorded being delivered to Luddenham Pet Meat. ( ABC News )

For the past 10 months undercover investigators have infiltrated Camden Horse Sales, a livestock auction, recording vast numbers of branded, registered racehorses passing through the yards.

The ABC has confirmed that Camden Horse Sales is not approved by Racing NSW to sell racehorses.

But vision provided to the ABC reveals racehorses sold to killbuyers, and ending up at knackeries including Luddenham Pet Meat.

The slaughter of racehorses is not illegal in Australia but it is against Racing NSW policy and rules.

Thoroughbreds identified at Luddenham Pet Meat in the last 10 months Courtney's Luv

Courtney's Luv Unbuckled

Unbuckled Startreusse

Startreusse Rebel Prince

Rebel Prince Perfectly Spun

The ABC has confirmed Luddenham Pet Meat is supplying mince to the greyhound racing industry.

It also supplies boarding kennels and pet shops.

When contacted by the ABC, Luddenham's owner, John Pace, declined to answer any questions.

Mr V'Landys said he had no knowledge that racehorses are being fed to greyhounds.

"I have no evidence of that," he said.

"I have had no reports from anyone, other than yourself today, that that is happening."

Mr Celotto is appalled at the possibility that greyhounds could be being fed racehorse meat.

"For Luddenham to be accepting racehorses that are protected by the New South Wales rules of racing, is abhorrent," he said.

"When you really think about this cycle of breeding, using and disposing of them, it's grotesque.

"How it's allowed to continue is beyond me. And it needs to come to an end."

Burns Pet Food, Riverstone, NSW

Burns Pet Foods has also accepted racehorses to be used in its pet food. ( ABC News )

The ABC has also uncovered racehorses being sold to another knackery, Burns Pet Food.

Thoroughbreds identified at Burns Pet Foods in the last 10 months Legal Waves

Legal Waves Hard Reign

Hard Reign Reliable Kingdom

Reliable Kingdom Explore The World

Explore The World Grand Icon

Grand Icon Cloverdale

Cloverdale Next Of Kin

Next Of Kin Halo's Image

Halo's Image Tahitian Black

When contacted by the ABC, Burns Pet Food refused to comment, beyond saying that the knackery only slaughtered sick horses.

The ABC has also confirmed that standardbred horses from the trots are being slaughtered too, despite NSW Harness Racing's "life-long tracking and care of standardbreds".

In an interview with the ABC, the CEO of Harness Racing NSW, John Dumesny reaffirmed the code's commitment to animal welfare and the rehoming or retiring standardbreds.

Harness Racing NSW published a commitment to the tracking and rehoming of standardbreds in 2016.

But three years on there is still no rehoming strategy in place.

"We're developing it. We have a not for profit company being formed," CEO John Dumesny told the ABC.

"We're continuing to develop it."

'This will shake the industry to its core'

Professor Paul McGreevy says the footage of the slaughter and mistreatment could prove to be a pivotal moment for the industry. ( ABC News )

The next three weeks see some of racing's biggest events, including the Melbourne Cup and the Everest.

Millions of dollars will be spent on promotion and millions more wagered by punters.

But behind the glitz, the industry is struggling with the brutal reality.

"The problem is massive," Mr Celotto said.

"They're breeding more than they need, hoping that they can breed the one that's going to be the next Makybe Diva or Winx, the next Black Caviar."

"The truth that's been revealed by these videos is that thoroughbreds are entering knackeries and abattoirs, and that their treatment within those facilities can be appalling," Professor McGreevy said.

"I think we're at a fork in the road moment.

"There's no denying the footage. This is the sort of material that will shake the industry to its core."