This happens automatically in all grazing units when livestock eat a seed and pass it in another location. It cannot be stopped. Nutrient recycling from manure and urine can be managed relatively easily in a rotational grazing unit. This recycling causes the reuse of any nutrient consumed. At each deposit more forage grows, fewer numbers of weed herbage emerge, and the weeds are more palatable, causing more weed use and greater other forage production.
Nutrient recycling goes on indefinitely.
Higher stock densities cause increased browsing of broadleaf weeds, more physical abuse by trampling and lower weed populations. This happens in both fertilized and non-fertilized situations. Most weeds are either preferred or acceptable to grazing beef cattle. Relatively few weeds are useless as livestock feed. In this situation we might consider the analogy that fencing functions as a sprayer and the livestock are, in effect, the herbicide or mowing equipment.