The lab cats were then euthanized after USDA researchers were done with them, according to a group that targets wasteful government spending.

U.S. government scientists fed the remains of cats and dogs purchased from overseas to healthy cats here in the U.S. for research. That's according to a watchdog report titled "USDA Kitten Cannibalism." The report also claims the cats that were experimented on by the USDA's Agricultural Research Service were then killed.

The White Coat Waste Project (WCW), which works to end government-funded experiments on animals, said nearly 600 cats and dogs were purchased. Their tongues, hearts and brains were either fed to lab cats or injected into mice.

The purpose: to study parasites that could lead to toxoplasmosis -- considered to be a leading cause of death attributed to food-borne illness in the United States, according to the Centers for Disease Control and Prevention.

The animals collected include:

42 cats purchased at Chinese pet markets

48 stray cats rounded up in Ethiopia

34 cats purchased at a Chinese meat market

309 dogs acquired from a shelter in Colombia

120 unclaimed Brazilian shelter dogs

42 dogs destined for a Vietnamese meat market

WCW reports the project currently receives $650,000 per year in taxpayer funds, and that the Agricultural Research Service has spent $22.5 million and killed more than 3,000 cats for the project since 1982. But WCW said there are indications that the number of cats experimented on and killed may be higher.

"Particularly troubling is that some of these cats and dogs were purchased by the USDA from meat markets the some of the same Asian countries (China and Vietnam) that U.S. Congress roundly condemned for their dog and cat meat trades 'on cruelty and public health grounds' in a House Resolution unanimously passed in 2018," the report states.

Dozens of lawmakers have signed on to the Kittens in Traumatic Testing Ends Now (KITTEN) Act to permanently end the experiments, introduced by Sen. Jeff Merkley, D-Ore.

"DEEPLY disturbing that @USDA has been purchasing cats and dogs from notoriously inhumane meat markets in Asia, then feeding the meat to animals they're experimenting on," Merkley tweeted Tuesday. "We can advance scientific discovery while treating animals humanely -- we need the #KITTENAct NOW."

The Washington Post reports a USDA spokesman declined to comment on the allegations of feeding cats the meat of other cats and dogs.

The study also called out the USDA for euthanizing the cats after the experiments were done. WCW cited multiple government agencies in its claim that there is no reason to believe the lab cats would be harmful to the public and therefore should have been adopted out. The CDC website, however, states that animal-to-human transmission is a way humans can be infected because a cat that carries toxoplasmosis can pass the parasite in its feces.