BILLINGS, Mont. (AP) — Federal officials shut down an experiment on diseased wildlife from Yellowstone National Park after inspectors questioned government protocols for handling infected bison.

The U.S. Department of Agriculture program in south-central Montana examined whether administering birth control to bison would reduce transmissions of the disease brucellosis.

Brucellosis causes animals to prematurely abort their young and can be transmitted through birthing material. It also can infect people.

Documents released to the advocacy group Buffalo Field Campaign show the experiment was shut down last July after inspectors raised questions about keeping infected and non-infected bison in the same pen.

A month later, the government changed policies to effectively ban such practices going forward.

The Livingston Enterprise first reported the experiment's shutdown.

Department of Agriculture spokeswoman Lyndsay Cole says the research aimed to mirror how non-infected animals encounter brucellosis in nature.

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