JACKSON, Miss. — The chairman of the Senate Appropriations Committee and its subcommittee on defense, Republican Thad Cochran of Mississippi, has announced he will resign April 1 because of health problems.

The 80-year-old stayed home for a month last fall with urinary tract infections, returning to Washington in October to give Republicans the majority they needed to pass a budget plan.

Cochran said in a statement Monday that he will fulfill his responsibilities to Mississippi and the Senate “through the completion of the 2018 appropriations cycle.”

He was first elected to the Senate in 1978 after serving six years in the House.

Republican Gov. Phil Bryant will appoint a temporary replacement. Then a special election will be held to fill the rest of the term, through January 2021.