The news created major waves today, including on the commodity markets, where a rally early in the day saw cattle futures jump, on estimates that the market could see lower cattle weights. Read the entire CME Daily Livestock Report to see more analysis on the decision.

As Tyson Foods spokesman Gary Mickelson said in our story, the news about Zilmax, or zilpaterol, does not extend to the use of ractopamine, the other beta agonist, that is manufactured by Elanco as Optaflexx. So it's premature to say that those Tyson suppliers aiming for more carcass pounds will drop beta agonist usage altogether.

Read the Tyson letter to feeders here and click here for the response from Merck Animal Health, the makers of Zilmax.

For more perspective on the two products, here's also a link to a 2012 piece in Progressive Cattleman written by University of Wyoming beef nutritionist Scott Lake, detailing the distinctive targets feeders can see with either Zilmax or Optaflexx. The drawback with more Optaflexx usage would come from any buyers who sell the beef on the foreign market. Russia this year announced a trade restriction on any beef using ractopamine, the beta agonist ingredient in Optaflexx.

Also unknown: How will Tyson's decision affect other beef processors and their purchases of cattle that finished on beta agonists? As I noted last week in a blog post and from an AP story, beta agonists have already been rejected and then reluctantly approved by Cargill. And their usage has raised the eyebrows of clients such as Certified Angus Beef. Will others be far behind?

As some trade industry reporters have mentioned, the irony is how the decision from Tyson came right after cattle industry members at the National Cattlemen's Beef Association summer convention had just met to discuss the impact of beta agonists on cattle.

Whether you're a cattle feeder or not, now is definitely the time to read and follow the issue, which may have long-lasting implications for beef producers in the coming years.