This is not only something that we should be thinking about in terms of alfalfa and the effects it has on livestock, but ourselves and our families as well. This is really a great discussion point, I'm glad that someone took the time to post it and I hope that the rest of the forum starts looking into it for themselves. 80% of the GM corn and soybean crops in the United States are used in animal feeds, so unless you choose to feed straight oats or barley (at least until 2012 when there is a chance that the ok to grow these crops GM as well may be reality), chances are, the mixed ration that you feed contains GMO's. Also it is believed that the recent (over the past 10 years) spike in Cushing's Syndrome and other metabolic disorders have been brought on by the production of GM sugar beet crops. The scary thing with the alfalfa is that (like they have found with corn) the GM crops could cause the extinction of the non-GMO crops since they are a "covering crop." Scientists are now linking the sudden increase in equine cancers, heart attacks and allergies to GM crops - scary stuff.
Nutrena states right on their site that "Producing feed with non-GMO grains would be cost prohibitive."
Here is a list of companies that supply non-GMO feeds (there are quite a few in my area and I am working on speaking with them about their costs since most of them offer bulk feeds and I have been toying with the idea of setting up a silo on the farm to cut feed costs and utilize better offerings):http://nongmosourcebook.com/nongmo_sourcebook2011/us_suppliers.php?page=7
Another thing to look at when you select feed is the fact that most livestock feeds contain high amounts of antibiotics and most plants manufacture chicken, pig, cow and horse feeds together in the same plant - excluding Blue Seal. So the first 20 bags of horse feed that come off the belt in the plant contain huge amounts of antibiotics - gut flora / ulcers / proper digestion, anyone?
Anyway, if you are interested in keeping GMOs out of your home as well here is a link to a shopping guide that you can use when planning your trip to the store - there is also a mobile app for all you tech heads:http://truefoodnow.org/shoppers-guide/