Time may be running out for the famous horse-drawn carriages that carry tourists around New York City's Central Park. Mayor Bill de Blasio has already declared his intention to shut down the industry, saying it is inhumane to keep horses in modern-day Manhattan. While that debate could be over, at least one nagging question remains: What will become of the horses? Both sides insist they will find a sanctuary for the approximately 200 horses licensed to pull carriages in New York City. But drivers warn that shutting down the city stables might have the unintended effect of eliminating a rare outlet for surplus horses pouring out of the farming and racing industries - sending them faster to the slaughterhouse. "If they did not come to New York City, most of these horses would be dead," said Ian McKeever, an Irish carriage driver who owns nine Central Park horses. That's an argument that infuriates critics of the industry, who say the nation's unwanted horse dilemma is no excuse to preserve an inhumane business. "Anyone who cares about a horse wouldn't think that taking it and sticking it in Midtown traffic is the right answer to that problem," said Allie Feldman, executive director of a leading anti-carriage lobbying group, New Yorkers for Clean, Liveable and Safe Streets. Last year, roughly 140,000 US horses were sent to slaughterhouses in Canada and Mexico when they became unaffordable, or unprofitable, for their owners. The root of the problem was unregulated breeding, said Wayne Pacelle, president of the Humane Society of the United States. Every year, far more horses are produced than can possibly get lifetime, or even middle-aged, care. In Pennsylvania's Amish country, the source of many of the horses that work in Central Park, this oversupply plays out weekly at the New Holland Livestock Auction. Every Monday, buyers for foreign meat factories snap up horses - many still young and healthy - that once pulled ploughs, buggies and carts, or served as family pets. Carriage opponents note that, for a lot of horses, New York City is far from a permanent home. City records on 720 carriage horses from 2005 to 2013 show about 30 per cent spent two years or less on the job, according to an analysis by the Coalition to Ban Horse-Drawn Carriages. But carriage owners insist their horses are as healthy and happy as any in a well-run rural barn. Most live in one of four stables, hidden away inside old three-to-four-storey buildings on Manhattan's far West Side. On days they work, the horses clop through city traffic, amid honking cabs, before reaching the spots where they line up for customers near Central Park. Most of the rides are in the park itself, but the horses are allowed to visit a handful of other nearby attractions such as the Rockefeller Centre.