The mishna, M'nachos 71 amud 1, says:
קוצר לשחת ומאכיל לבהמה
That is, under the circumstances described there (not important for this question), one is allowed to cut his grain לשחת and feed the produce to his animal. What does "קוצר לשחת" mean exactly?
Pin'chas K'hasi translates "שחת" IIRC as מספוא, which modern-Hebrew dictionaries say means animal feed. That'd mean "קוצר לשחת" means "he may cut [grain] for animal feed" — but that's clearly incorrect in light of the g'mara (amud 2) that discusses קוצר לשחת and feeding humans ("לאדם מי שמעת ליה").
Nor can it be referring to cutting the grain at an early stage of development, as the mishna itself discusses קוצר לשחת when the grain is developed ("משהביא שליש").
So I suppose it must be referring to a certain method of cutting the grain. What method? Or, if not that, then what does it refer to?