junior,

Not sure of your location but here on the plains a question that quickly gets skipped in turn for cash (not that I can blame anybody) is what is residue worth to you. Depending upon your environment, tillage system, and rotation that maybe a lot or a little.

Also figure loss of nutrients.

Not trying to talk you out of it, suggesting some questions to think about.

If you go ahead I would definitely agree with the post about a nitrate test, most of the nitrates are in the bottom 6-8" (I think) of the plant. The recommendation around here was to take several whole plants and let the lab run analysis at different heights to determine a safe cut height.

I'm sorry its come to this for you, we've had too many years of that in my recent memory as well.  Our cows liked it (but they really didn't have a choice either!).

Lucas Haag

Guidelines for Nitrates in Feed - Olsens Ag Lab

UNL Beef Extension - High Nitrates in Corn and Other Summer Annuals