I was led to believe that stuff stayed in the rumen for three days, which allows us to feed two days straw, one day silage (or vice versa, depending on condition) to our dry cows without upsetting their digestion too much. If this is so, then the seeds will take at least two days to 'come through'. I noticed birds foot trefoil and meadow vetchling spreading round our pastures from one very flowery meadow, so last year changed the rotation to see if we could spread them backwards round the fields from the same starting point. In no hurry for instant results here...Possibly.It would take some doing , as you would probably need to have them go back and forth in the same day- i.e mornings in the seeded pasture, afternoons in the one needing the seeds.