A federal animal-research center in Nebraska will not be allowed to start any new experimental projects until it strengthens its procedures and internal oversight, the secretary of agriculture, Tom Vilsack, said Monday.

The decision came as a report ordered by Mr. Vilsack found that an oversight panel at the U.S. Meat Animal Research Center, in Clay Center, Neb., “was not adequately fulfilling its intended role” of scrutinizing experiments to ensure that they minimized pain and suffering for the animals. The report, however, said that during a three-day visit to the center in February, an investigating committee found no evidence of animal mistreatment. “Without exception,” it said, “the panel observed health and well cared-for animals.”

The report was prompted by a Jan. 19 article in The New York Times that raised concerns about the treatment of farm animals at the center, a 50-year-old unit of the Agriculture Department that aids the meat industry by developing livestock that are more productive and profitable. Interviews and internal records revealed that experiments and everyday handling of animals at the center have often resulted in illness, pain and premature death, and that the center lacked the careful oversight that many universities and meat producers have exercised over their own research.

Since the article was published, several members of Congress from both parties have pushed a bill to extend the federal Animal Welfare Act to shield cows, pigs, sheep and other animals used for agricultural research at federal facilities like the Nebraska center. The law, enacted in 1966, excluded those animals, focusing largely on cats and dogs used in laboratory research. Some animal-rights groups have urged that the center be closed.