Although we don't believe in timing the market or panicking over market movements, we do like to keep an eye on big changes -- just in case they're material to our investing thesis.

What: Shares of AgFeed Industries (Nasdaq: FEED) surged 12% in intraday trading. It appears that the shares were caught up in the excitement as the entire agricultural sector reacted to the Department of Agriculture's announcement on the state of the corn harvest.

So what: If my assumption is correct that AgFeed is simply riding the excitement in the rest of the ag world today, then there may be reason for concern with today's share pop. AgFeed's two primary businesses are developing animal nutrition products and hog production. If the USDA's announcement today has any effect on AgFeed, it would likely be negative as higher corn prices would increase the company's hog-raising costs and it could also reduce farmer demand for hog feed.

Now what: If your interest is in making the most of today's USDA announcement, then I'd skip AgFeed and head for one of the companies that's more likely to benefit from the lower-than-expected harvest. CF Industries (NYSE: CF) and Intrepid Potash (NYSE: IPI) have both had double-digit jumps on the news, but you can expect that the light harvest could benefit most fertilizer companies, including Mosaic (NYSE: MOS) and PotashCorp (NYSE: POT). Even beleaguered Monsanto (NYSE: MON) could benefit from the news as it sells corn seeds to farmers.

Interested in more info on AgFeed? Add it to your watchlist by clicking here.

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Fool contributor Matt Koppenheffer does not own shares of any of the companies mentioned. You can check out what Matt is keeping an eye on by visiting his CAPS portfolio, or you can follow Matt on Twitter @KoppTheFool or on his RSS feed. The Fool's disclosure policy assures you no Wookies were harmed in the making of this article.