LINCOLN, Neb. — The closing of the country’s last meat processing plant that slaughtered horses for human consumption was hailed as a victory for equine welfare. But five years later just as many American horses are destined for dinner plates to satisfy the still robust appetites for their meat in Europe and Asia.

Now they are carved into tartare de cheval or basashi sashimi in Mexico and Canada.

That shift is one of the many unintended consequences of a de facto federal ban on horse slaughter, according to a recent federal government study. As the domestic market for unwanted horses shrinks, more are being neglected and abandoned, and roughly the same number — nearly 140,000 a year — are being killed after a sometimes grueling journey across the border.

“When they closed the plants, that put more of a hardship on our horses than the people who wanted to stop the slaughter can imagine,” said John Schoneberg, a Nebraska horse breeder who recently took in three horses from a nearby farmer who said that he was unable to pay for feed and would otherwise turn them loose.

The study’s findings have been fiercely contested by animal welfare groups, which argue that most of the problems stem from the economic downturn and the high price of feed. The study also breathed new life into the long-smoldering battle over whether to allow the resumption of domestic horse slaughter or, alternatively, to prohibit the animals from being shipped abroad for their meat.