Missouri officials have approved tougher regulations for deer ranchers and hunting preserves in an attempt to prevent the spread of disease.

The new rules approved Friday will ban the importation of deer from other states and require testing for chronic wasting disease on deer at least 6 months old that die in captivity.

Most of the new rules are expected to take effect Jan. 30. But existing deer farms and hunting preserves would have until June 30, 2016, to meet guidelines for stronger fences.

The state's captive deer industry has said the regulations could cripple its business. It plans to file a legal challenge against the authority of the Missouri Conservation Commission to regulate captive deer.

The commission did soften some of its proposals Friday, dropping a plan for double-fencing.