The general grazing/feeding restriction after the use of glyphosate herbicide is 60 days. However, this can vary with the formulation or specific glyphosate product that is used; so check the product label. Although I am not completely certain of the management objectives for this particular field, it may be better to harvest for hay first; and at a time sufficient for at least some regrowth to occur, apply the glyphosate to kill the grass.
