Seed response to grinding in a hammer mill or extrusion through a pellet die was determined. Less than 1% of spotted knapweed, sulfur cinquefoil, timothy, and alfalfa seeds were intact after grinding to pass through a 1-mm screen. Intact seeds of all tested species except sulfur cinquefoil were able to germinate after grinding. Extruding unground alfalfa seed through a die to make hay pellets decreased viability 60 to 63%. After grinding and extrusion through a grain pellet die, 53% of intact alfalfa seeds in the pellets were viable. These data demonstrate that feed pellets can contain viable weed seeds.
