I dont have the sack lying around, but the Mummes feed store as well as the Barkleys have them. I remember at least one brand being the purina. It wasnt cheap though, like 15 for a 50# bag.
I think they are local only, so if you are around the SA area, maybe you can stop by one, but you should be able to at least get the brand name of the stuff
Hope this helps, maybe you can try thier websites at...
http://www.mummesinc.com/Barkelys is a local place, but try this..
Barkley's Home & Ranch Center
32450 Ih 10 W
Boerne, TX 78006 Map
(830) 249-2656