How quick does hairy vetch regrow after cutting? (Yes I'm aware of toxicity concerns, but I'll be cutting early--mid bloom or so--before seed forms.)

I was going to let it get bigger and no-till corn into it, but now plan to take off a cutting of baleage (vetch + crimson clover + triticale) first. I'll cut 4" high to encourage some regrowth (esp. of the trit.) and need enough regrowth for 2,4-D to get a good kill on the vetch. (Glyphosate should take care of the crimson & trit.).