Washington, Dec 20 (IANS): US Senator Jeff Merkley has introduced a Senate bill aiming to stop the Department of Agriculture (USDA) researchers from euthanising kittens used in their work.

Merkley 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," the Oregon Democrat was quoted as saying by CNN.

The kittens are used in research into toxoplasmosis -- a parasitic illness, which can be serious for unborn children and people with compromised immune systems.

They are killed after the research, but Merkley said they should be adopted instead.

He said veterinarians had told him the kittens, which are euthanised before they are three months old, could be treated for the parasite and emerge "very healthy".

USDA's Agricultural Research Service, which runs the testing, did not comment on Merkley's move.

A USDA spokesman had earlier told CNN that the use of cats was "essential" to the research to combat a widespread parasite and that the agency "makes every effort to minimize the number of cats used," calling the 100 figure a "serious over-estimation".

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

The KITTEN Act's House of Representatives version was introduced by Republican Rep. Mike Bishop, and now has 61 co-sponsors, including both Republicans and Democrats. Bishop lost his re-election bid last month.

Merkley said he hopes to make the effort bipartisan in the Senate, too, when members return in the new year and that he may discuss the issue with Agriculture Secretary Sonny Perdue.