Butter stocks rose a whopping 22 percent from March to April and 22 percent from April 2012.

According to the U.S. Department of Agriculture’s “Cold Storage” report on Wednesday, butter stored in warehouses rose from 255 million pound in March to 310.66 million pounds in April.

Total natural cheese stocks in refrigerated warehouses rose slightly, climbing 1 percent from last month.

It's a "bearish" sign on butter prices, says Dave Kurzawski, dairy analyst with FCStone in Chicago.

FCStone expects butter futures to feel downside pressure as "reports of stocks" will continue to grow during May.