For years, animal rights advocates had relied on a government database to identify dog breeding facilities, research labs, and zoos that had been cited for health and safety violations. Seven states used the data to enforce laws that seek to prevent animal abuse.

But in February, federal officials abruptly removed the information from the site, citing litigation and concerns from some breeders that the information could be used by environmental terrorists to target them.

Delcianna Winders, a fellow at Harvard Law School at the time, immediately filed a public records request, seeking information that could provide a more detailed explanation for why the records were removed. Three months later, she received 1,771 pages — all completely blacked out.

“It was a brazen, absurd, and unlawful response,” said Winders, now a vice president at the People for the Ethical Treatment of Animals in Medford. “I’ve never seen anything like that.”

Since then, Winders and PETA have teamed up with the Massachusetts Society for the Prevention of Cruelty to Animals and other animal welfare groups to sue the US Department of Agriculture, alleging that its removal of the reports has stymied the ability of independent groups to expose mistreatment of animals.

Without the information, long available as a searchable database on the site, animal welfare advocates say it will be next to impossible to identify who has been cited for failing to provide animals with sufficient water and food, safe cages, and veterinary care.

“We used these records to show that some breeders shipping animals to Massachusetts failed to treat their injuries or kept them in dangerous or unclean housing,” said Laura Hagen, deputy director of advocacy at the MSPCA in Jamaica Plain, one of the nation’s oldest humane societies. “Now, it’s much more difficult to do that.”

The removal of the records, which coincides with the purging of data from the US Environmental Protection Agency and other federal departments, is a less-publicized example of the Trump administration seeking to protect businesses at the expense of consumers, Hagen and other critics said.

Animal rights advocates had relied on a government database to identify dog breeding facilities, research labs, and zoos that had been cited for health and safety violations. USDA photo

“It’s certainly another step into the realm of less transparency and consumer protection,” Hagen said. “Everyone has been dumbfounded by this.”

In a statement, USDA officials said the removal of the records was part of  “a comprehensive review of the information it posts on its website for the general public to view.”

When the agency blocked access to the records, agency officials said they would remain accessible to the public through Freedom of Information Act requests. But those requests can take months or even years before being approved.

“We continue to work on the database to ensure that we can provide a searchable database while protecting personal information,” said Tanya Espinosa, a spokeswoman for the USDA’s Animal and Plant Health Inspection Service.

In February, the agency cited ongoing litigation by groups mentioned in the database as a reason for removing the records. Officials didn’t cite a specific case, but the agency had been sued by members of the Tennessee Walking Horse industry, who argued that the information had been used to disparage them.

Shortly after the agency removed the records from its website, the plaintiffs withdrew their claims and said their objectives had been met.

The plaintiffs have threatened to resume their litigation if the agency republishes the database.

“A lot of people who raise and breed animals are basically at risk of domestic terrorism and harassment because of these records,” said Mindy Patterson, president of the Cavalry Group, a Missouri-based advocacy group for animal breeders and similar businesses.

Tennessee Walking Horse owners are regulated, in part, to prevent cruel practices that involve the use of chemicals that stimulate the horses to high-step.

Some breeders, she said, have been the victims of violence as a result of the database.

“A lot of these public records have been abused and used by some groups for nefarious means,” Patterson said. “That’s why we remain in favor of keeping this information private.”

Animal rights advocates dismiss such charges, saying the records should be easily accessible to the public because exposure helps reduce illegal activity and allows them to keep tabs on whether regulators are enforcing the law.

Ryan Merkley, director of research advocacy at the Washington-based Physicians Committee for Responsible Medicine and a co-plaintiff in the lawsuit against the agency, called the suggestion that the USDA is seeking to protect the privacy of breeders a “flimsy argument.”

The agency already redacts personal information on their inspection and enforcement reports, he and others noted.

“There are powerful industries regulated by the USDA that don’t like the public knowing they violate the law,” he said. “The public should know when there are violations. We feel the USDA is bending to the industry, at the cost [of] the public.”

The removal of the database also would make it impossible to enforce a proposed animal welfare law in Massachusetts, its supporters say.

The Act Relative to Protecting Puppies and Kittens seeks to protect the public from adopting pets that are unhealthy and come from unsanitary breeders. The bill would ban the sale of pets in Massachusetts from breeders that have been cited over the previous three years for violating federal law.

Without the records available on a public database, the state would have no way of checking whether the breeders have complied with the law.

“It’s outrageous that the government has taken down this information,” said state Senator Karen Spilka, an Ashland Democrat, who has sponsored the bill. “It makes you wonder what these people have to hide.”