An effective means to destroy weed seeds in livestock feed is to ensile the forage. The fermentation process destroys nearly all common annual grass and broadleaf seeds. Even most of the hard seeds of velvetleaf are killed. Straw used for bedding is frequently infested with weed seeds and these, too, will cycle through the animals and back onto the fields. Composting manure will reduce but not eliminate viable weed seeds.
Poultry are more effective in destroying weed seed than ruminant and monogastric animals.
A recent concern that adds more importance to a vigilant prevention program is the appearance of herbicide resistant weeds in the U.S. Feed or crop seed contaminated with weed seed may well not bring a new species to a farm, but rather a new gene - one that may greatly reduce the performance of current weed management programs. It is impossible to visually separate resistant plants or seeds from their susceptible biotypes. The difference is at the gene level and is not evident in any external characteristics. One means of preventing weed introduction and spread is via the legal route. For example, governments may decide to quarantine infested areas to prevent further movement of a serious weed problem.