A bill to encourage the adoption or retirement of animals no longer needed for research in federal labs has the support of U.S. Sens. Susan Collins of Maine and Jeanne Shaheen of New Hampshire.

Supporters say more than 50,000 cats, dogs, monkeys, rabbits and other animals regulated under federal law were used in labs in 2018. They say many animals are killed when federal agencies lack policies on adopting or retiring animals no longer needed for research.

The bill introduced Tuesday would direct federal agencies to have such policies.

Collins, a Republican, says the bill would build on policies at agencies such as the Department of Defense. Shaheen, a Democrat, says retiring animals should get the chance to live in caring homes.

Co-sponsors include Sens. Gary Peters of Michigan, a Democrat, and Martha McSally, of Arizona, a Republican.