"Most people don't get up after they've been hit by one of those," she says mildly now, telling the story as she sits in a Sydney cafe on a recent visit to Australia. Beside her is her husband, Carey Theil, fighting jet-lag but smiling at the miracle of his wife. Somehow Dorchak survived, with a broken back, broken neck, a serious head injury and the grand theft of her past. For Dorchak had forgotten everything, from how to write to how to recognise her own parents. Only one tendril of recollection remained.

"I woke up from my first coma and I had lost all of my memory except for one thing: my dog. All I could get out was, 'How's Kelsey? What happened to Kelsey?', before I slipped back into my coma. When I woke again, I asked the same thing. It was all I could think of."

She asked after the dog so often, the hospital gave special permission for Kelsey, whose injuries had required a hip replacement, to visit. Dorchak's memory never returned but the powerful sense of a debt to Kelsey remained. "I felt that she had saved my life but I had this belief she had pulled me from the full brunt of the impact and I thought, 'If I ever get up again, I'm fighting for dogs.' " It took her a while to work out how.

"About four years later," she says, "I learnt there were these two facilities in my state where there were about 1000 dogs each, living in small cages, taken out three or four times a month for racing. "Sometimes they would die for their efforts [on the track]. And if they got too old or didn't run fast enough, they'd be killed. And I didn't like it."

The animals, of course, were greyhounds. In 2001, Dorchak and Theil formed GREY2K USA, a greyhound protection and advocacy group. Dorchak even undertook a law degree to equip herself. (Kelsey died soon after Dorchak graduated: "I think she figured she had done all she could and now it was up to me.") 

Dorchak and Theil came to Australia to talk to authorities and cheer on local activists with stories of GREY2K's successes, amid the usual defeats, in the US. GREY2K's mission is to see greyhound racing wither and die in the eight countries of the world that still have commercial greyhound racing. The withering, they believe, is well under way. They don't claim all the credit and welfare concerns aren't the only reason, but the sport is now illegal in 39 states of the US. "When we started," says Dorchak, "there were 59 dog tracks in 15 states. Now there are 20 in six states."

The couple arrived here like harbingers of doom for the Australian greyhound racing industry, an industry still worth $3.5 billion a year but beleaguered by scandals about live baiting; the discovery of "death pits" bony with massed greyhound carcasses, some with bullet holes; the fatal export of greyhounds to Asia; doping allegations; and continuing concern about alarming levels of euthanasia on healthy dogs.

Australia's story is almost a mirror image of what has happened in the US, say Dorchak and Theil. "We've had your scandals," Dorchak says in her soft Massachusetts drawl. "We've seen it happen. We know how it ends."

They are typical of the animal welfare campaigners greyhound racing increasingly finds itself up against; activists relying on facts as much as feelings and now riding a wave of community outrage. Loathed by many in the greyhound game as "animal liberation nuts" bent on destroying the industry (that part is true), they're certainly determined and single-minded, the kind of people willing to go vegan and pledge a lifetime's allegiance to a species other their own. The kind of people who get hit by a train and get up again.

The lights are on at Wentworth Park in inner-Sydney's Glebe, but it looks like nobody's home. Saturday night and the stands are deserted. Inside, there are only a couple of hundred; the young and the desperate, the first hoping for a lark, the second for a lucky streak. The real action hasn't been here for a long time. It's at the TAB and online. In the on-course kennels, the trainers are readying the greyhounds for the next race. Some are patting their dogs, one is kissing hers.

Sentiment, however, only goes so far when it comes to greyhounds. They're the skin in the game, the dog in the fight; useful as long as they can run faster than the other dogs. Respected, loved even, but, in the end, closer to a throw-away commodity with a wagging tail. It's a business, and these painterly dogs are its mute, indentured labour force, put to work in a multi-billion-dollar gambling industry that offers them lousy conditions and an early retirement plan, frequently fatal.

In February this year, ABC's Four Corners aired an exposé of live-baiting in the greyhound industry. Viewers were horrified to see undercover footage showing live animals, from piglets to possums, being used as lures and mauled by greyhounds worked up to fever pitch. One scene showed a little girl being allowed to watch as an animal was torn to pieces.

The callousness shown by the trainers, handlers and owners, who included some of the top names in the sport, coupled with their barefaced lies, appalled the nation. It was catastrophic for an industry already scarred by similar scandals in the past. Suspensions, lifetime bans and criminal proceedings followed. Boards were disbanded, chief executives toppled. Everyone insisted they were shocked.

But it didn't end there. In August, the ABC obtained disturbing internal documents from Greyhound Racing NSW that suggested GRNSW's biggest concern was with the fallout. The documents revealed cover-ups, tip-offs, mismanagement and cynicism within the NSW regulator, also the sport's promoter.

They showed that days before the Four Corners program, then chief executive Brent Hogan had been canvassing ways to spin adverse revelations and stay sweet with the state government (a revenue loop means millions of tax dollars are funnelled back into the industry.)

"We are in a position where politically we need to be seen to be doing something of significance and independently," Hogan wrote to staffers. In a private email, he flagged the option of setting up what sounds like a bogus taskforce: "Appoint a panel headed by a prominent QC ... a technical expert (f... knows who this is but must be independent of us, like a head of a vet school or some dog whisperer with a PhD), and a probity/process adviser ... will give government comfort."

(A NSW government special commission of inquiry headed by QC and former High Court judge Michael McHugh is currently under way but yet to report.) Soon after the program aired, the RSPCA raided several properties. An annoyed GRNSW staffer grumbled that they hadn't been forewarned: "Hard to trust [the RSPCA] again now. They have burnt us bad."

At the time, RSPCA chief executive Steve Coleman said he was "appalled" by the revelations: "It flies in the face of the term 'integrity' if people are being forewarned about the onset of an inquiry or an investigation by the RSPCA."

Amid the live-baiting furore, it was easy to forget about the silent bystanders: the greyhounds themselves. "The day-to-day life of a greyhound – how they are housed, their lack of social interaction, lack of play – is one of absolute deprivation and that's forgotten," says Lyn White from Animals Australia, which, with Animal Liberation Queensland, supplied the secret footage to Four Corners.

"These dogs are generally kennelled in small enclosures. They are only required to be brought out for two periods of 15 minutes a day and often they're forced to exercise on treadmills, not outdoors."

White says we need to change our perceptions. "We're conditioned to think, 'Oh, greyhounds are bred for racing, so that's their purpose.' Greyhounds are no different from any other dog."

Not everyone agrees. In a submission to a greyhound racing inquiry in May this year, Lloyd Klumpp, general manager of Biosecurity Tasmania (part of that state's primary industries and environment department), noted that while the general public might be concerned about greyhound "wastage", it didn't constitute a legal problem under the Animal Welfare Act. "Greyhound racing is a livestock industry," he declared, "and like all livestock industries there will be excess or cull animals that need to be disposed of by euthanasia or slaughter."

Others in the industry regard them as "working dogs". Either way, they're seen as more expendable than the family spaniel. The execution rate of healthy greyhounds is horrifying. Most greyhounds, a breed that can live 10 to 15 years, don't make it past three or four. Animals Australia believes around 18,000 dogs – including young, injured and retired greyhounds – are killed each year in Australia. "Out of 20,000 dogs born each year, only 2000 will go on to live a full life. We estimate 90 per cent of healthy dogs are killed simply because they haven't run fast enough," says White.

The RSPCA agrees that thousands of unwanted greyhounds – many of them "wastage" from overbreeding – are put down despite being otherwise healthy and suitable for rehoming. Poor record-keeping means no one has precise figures, not even the regulators. An internal industry report hazarded a figure of anywhere between 13,000 and 17,000 a year, but added that it wasn't known how many thousands were being re-homed by charity groups or living out their lives on owner properties, so the lower figure was more likely.

It's still unacceptable, agrees Scott Parker, CEO of Greyhounds Australasia, the representative body of the state regulators. His aim is for "zero unnecessary euthanasia" by mid 2020. For a greyhound with its life in the balance, much hangs on the word "unnecessary". Parker is reluctant to pinpoint where the boundaries of "necessary" euthanasia start and finish and offers some corporate-speak about stakeholders, non-industry perspectives, "levels of agreement that speak to milestone improvements in animal welfare", and so on. In other words, what is the public willing to cop when it comes to killing greyhounds?

"We have to educate people as to what 'zero unnecessary' actually is," he explains when we meet at Victoria's Sandown greyhound track. "My expectation is that [if you asked the community what level would be acceptable], at first people would say, 'Zero', but then, being exposed to some of the context around which zero might be possible or impossible. The fact is, catastrophic injuries sometimes happen. Sometimes greyhounds are bitten by a snake, they're hit by cars on the road ... accidents happen, so they can't be included [in the unnecessary]."

Still, it's hard to see how the greyhound business could survive commercially by euthanising only those dogs that fall victim to snakebite or car accidents. About 200 dogs a week are injured while racing, although not everyone considers that an accident.

"They're thin dogs," says Christine Dorchak, "they have the lowest body fat of any dog and if you put eight of them in a line and you say, 'Go!' at 60 or 70 kilometres an hour, and they 'bump' into each other, as the industry likes to call it – I call it crash – their bones break. A broken-legged greyhound is a worthless dog. Very few trainers are going to spend around $1000 to rehabilitate that dog."

Greyhound vet Dr Ted Humphries, persona non grata with the greyhound industry after blowing the whistle on corruption in the '90s, says he has frequently offered to euthanise dogs free of charge, to spare them a more brutal death. He claims to have seen bodies of dogs that have been hanged or bludgeoned with a hammer. Most trainers and owners, Humphries says, are "decent people who have a genuine affection for their dogs and don't enjoy euthanising them" but they're running a commercial enterprise. On the upside, he believes death rates have dropped somewhat as a result of more rehoming and prohibitive breeding costs.

The industry likes to trumpet its Greyhound Adoption Program (GAP) and others like it but, in truth, there are simply not enough homes for all the excess pups that never go on to race or older dogs that are deemed, as Humphries puts it, "beyond their useful life". Only a minority will meet a happy end.

Spring has arrived at Brightside farm Sanctuary, in the Huon Valley outside Hobart. The branches are fat with bud, and donkeys, draught horses, sheep and camels graze together on the new grass like odd-couple leftovers from Noah's ark. Near the house, it's all quacks and squawks, exuberant barking and the grunting of pigs luxuriating in dust baths. In a run to one side, four recently rescued greyhounds madly wag their tails in welcome.

Every animal here bears a shameful story. A beagle kept on a chain for nine years, horses starved, hens turned into bald scarecrows in factory farms, the 32 miniature pigs kept inside a house for two-and-a-half years. It's like a gallery of human indifference.

Brightside's owner, Emma Haswell, appears at the door and calms a posse of house dogs. She's a tall, attractive woman with curly hair and the harried air of a Saint Francis overwhelmed by the scale of the task.

Haswell spent years in undercover animal welfare work, sneaking illegally into factory farms with a camera and sometimes coming out with a mistreated piglet or hen stuffed under her jumper, but the stress of seeing all that suffering nearly did her in. She now concentrates on greyhound rescue.

In the house, a poodle rescued by Haswell from a puppy factory is sprawled on the sofa and an orphaned lamb stalks about on unpractised legs. A pearly greyhound sidles over to rest against my thigh and raises eloquent eyes. Her gentleness peels away all my childhood impressions of greyhounds: aggressive, characterless, remote, frightening in their muzzles. It takes me a moment to notice the muscled stump that used to be her back leg, amputated after being shattered in a race.

Haswell didn't become an animal activist after being hit by a tram, but she did have an epiphany. The former sheep farmer and veterinary nurse saw a flyer at a charity dog show while she was living in London 12 years ago. "It said, 'Stop Australia exporting greyhounds to Asia'. Later I saw an image of a side of greyhound meat, lying with its long tail on a meat market table in Asia, and I just felt sick. I thought, 'That's an Australian greyhound.' It would have been a failed racing dog in Australia that had been exported to Asia, raced there and then used for meat.

"I went from a sixth-generation meat-eating farmer to a vegan animal rights activist in a short period of time. Back in Melbourne, I heard somebody had buried a greyhound alive under a sheet of tin in Granton [Tasmania] and cut her ears off so she couldn't be identified, and that's when I found my voice."

She has since rehomed 400 and demand is growing. Her hope is that people will get to know greyhounds better and call for an end to what she considers their exploitation for entertainment and gambling.

"I started with one or two a week, but it was hard to find homes for them. Trainers didn't want to give them to me. Too much trouble. They'd rather put them down. They'll say to me, 'You've got to be here within 24 hours, otherwise I'm going to shoot it.' They want to bring another dog into the kennels straight away."

Two of the hounds settle beside us on the verandah. "How could you have a dog like a greyhound and just knock it off so you can replace it with a faster one?," she asks. As if to prove the point, the lamb skitters out and the dogs ignore it.

Ex-racers are not without their problems as pets, but Haswell is something of a greyhound whisperer. "When the dogs arrive, a lot have a keen chase instinct, so I put them in paddocks and pretty much leave them alone for a few weeks. The longer they sit and do nothing, the more relaxed they become. A lot will almost train themselves out of chasing.

"I know from talking to the trainers who I deal with, most greyhound puppies don't chase. They'll tell you that they have to encourage them to chase, whether they use a lure or a ball or a live animal, or a skin, or a rag that smells good, and some of them still won't. Others will chase and aren't fast enough."

As animal welfare issues go, improving the lot of greyhounds isn't a herculean task, Haswell insists. "It's a relatively small industry. It's not like factory farming, where we talk about making the lives of 470 million chickens better.

"If it was any other breed of dog, this mass killing would not be accepted. No one would tolerate it if it were golden retrievers or poodles or Labradors."

The greyhound industry has taken to airing heart-warming advertisements to signal its new consciousness: "Greyhound racing – embracing change." It is hoping reform can save it, or at least improve its image. "Reform greyhound racing?" one activist splutters. "It's like trying to reform child slavery."

Scott Parker acknowledges that while the industry has met its financial and legal obligations, it hasn't adequately considered "the moral obligation", and that has to change. "We don't have a choice," he continues. "The industry can't continue to operate [for example] on the basis that euthanising greyhounds when they're perfectly healthy is acceptable to the community."

Parker, who has only been in the chair 18 months, ticks off some of the reforms on the agenda: more money for welfare and adoption programs; more targeted breeding to reduce the number of excess dogs whelped; fewer litters per bitch; better lifetime tracking of dogs so they don't just disappear; a broader licensing system; more transparency, more education.

But the greyhound business isn't neatly kennelled in a capital city. It flourishes in tiny rural and regional centres, on country properties, behind the fence in suburban backyards. If the regulating bodies didn't know about the mass graves and the live baiting, even after formal alerts from animal activists, what chance is there of policing all that? And what about funding?

But there's a more central question here. Is it even possible for the greyhound racing industry to be run humanely and survive commercially?

Yes, insists Scott Parker, who envisages a "dialogue" between all "stakeholders" – including animal activists – to reach the "sweet spot" that keeps everybody happy.

Racing's opponents, and even some of its enthusiasts, believe it simply can't be done. "You cannot regulate out the cruelty of greyhound racing," says Dorchak. "It would put it out of business, and it is a business. Dogs are going to be overbred to get the fastest ones, dogs are going to be injured and die while racing, dogs are going to be in excess – there won't be enough homes for them at the end of the day – so in no way is dog racing ever good for dogs."

It is, however, good for gambling. Says NSW Greens MP John Kaye, a long-time campaigner to end greyhound racing: "The biggest problem we've got is not the greyhound industry itself but the wagering industry. That's where the big money is, and they will fight."

So, a few bad apples and some outdated practices that need to change, or an entrenched culture with its eyes on the prize and blind to its own brutality? An industry genuinely willing to reform or an industry that can't reform without sowing the seeds of its own destruction? And what hope is there if even officials can't recognise the common borders of cruelty?

Vet Ted Humphries tells a story from a previous live-baiting scandal: "A head steward said to me [when the baiting was exposed], 'You know, it's possible someone could go to jail for giving a rabbit to a greyhound. Hell, it's just a few bunnies! I mean, a man's going to go to jail for that.' "I thought, 'Well, why not?' " 

74%

Proportion of dogs reported as "retired" but later recorded as having being euthanised

5 greyhounds a week 

Number killed on the track or euthanised afterwards because of injuries

18,000+

Number of greyhounds bred each year