SIOUX FALLS, S.D. - Lawyers representing cattle, consumer and health interests urged a federal judge in Sioux Falls today to stop imports of older Canadian cattle because of the potential threat of mad cow disease.

An attorney for the federal government countered that a preliminary injunction should not be granted because rules and changes in the industry do a good job of protecting American animals, people and markets.

The lawsuit was filed last fall.

It seeks to suspend a U.S. Agriculture Department rule that took effect in November that allows Canadian cattle more than 30 months old into the U.S. market.

R-CALF Stockgrowers of America and the South Dakota Stockgrowers Association are among the groups that filed the lawsuit.