USDA says it resolved dozens of export issues in 2012 that freed up an estimated $4 billion in agricultural exports last year, protecting roughly 30,000 American jobs in the process. Agriculture Secretary Tom Vilsack says the effort required constant monitoring of world markets to ensure the trade system stayed open and fair. The monitoring effort included working to eliminate barriers, open new markets, secure the release of US shipments detained at foreign ports, and ensure the safe movement of agricultural products.