Washington (CNN) Democratic Sen. Jeff Merkley is joining forces with a Republican congressman to stop Agriculture Department researchers from euthanizing kittens used in their work.

Merkley told CNN he introduced on Wednesday a Senate version of the KITTEN Act -- officially, the "Kittens in Traumatic Testing Ends Now Act of 2018."

"The USDA breeds up to 100 kittens a year, feeds them parasite-infected meat in order to have the parasite's eggs harvested for use in other experiments, and then kills the kittens," Merkley said. "This bill would essentially stop this process."

USDA's Agricultural Research Service, which runs the testing, did not immediately respond to a request for comment on the legislation Wednesday afternoon. A spokesman told CNN in May the use of cats is "essential" to the research to combat a widespread parasite, and it "makes every effort to minimize the number of cats used," calling the 100 figure a "serious over-estimation."

The Agriculture Department says the cats aren't put up for adoption because of the potential risks to adoptive families.

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