You have too much growth as it is now - the grass is reaching senescence and isn't going to be eaten down fast enough to prevent quite a bit of waste.

Hay it off, then allow it to grow out to a point where you can graze it off from one paddock through to the last without reaching full development on the grass again.

You don't want to graze perennial forage grasses closer than about 3" at the very minimum. You get faster re-growth if you allow 4" of stubble. #1 thing that kills perennial grasses and reduces production is cutting/grazing too close - the grass needs that stubble to store carbs and energy for re-growth. It isnt in the roots, as it is in alfalfa - it is in the stubble. Winterkill happens fastest on pastures that have been grazed far too close before winter freeze-up.

Remember to put on P as well as N. The P is needed on most soils to provide for root re-growth in the fall. If you don't have good root re-growth this fall, your ability to see a yield response from adding N next year is limited.