Questions like 'what's the story behind fodder?' are so much grist for our word mill. That reflection reminds us that grist and fodder have a lot in common: among the oldest words in our lexicon, they both claim Old English ancestry, where they enjoyed strictly literal senses, and moved into the modern ages with metaphoric meanings. (来源：EnglishCN.com)

Fodder developed from the same Old English ancestor as food. Long, long ago, fodder meant "food" or "provision." That sense is no longer in formal use, but fodder still names "something fed to domestic animals, especially coarse food for cattle, horses, and sheep." Coarse fodder, containing a relatively large percentage of crude fiber or water, is also known as "roughage."

Any farmer knows animals eat large quantities of food; the connotation of something used to supply a constant demand fed the metaphoric sense of fodder naming "something to be consumed." This meaning broadened to include the creative "raw material for artistic creation" sense, the slangy "ammunition" sense, and the sobering sense naming "human beings regarded for a certain purpose as an undifferentiated mass," such as the one intended in such terms as cannon fodder.