Just under 1000 in number, the farmers supply leading US organic dairy firm, Organic Valley. In a statement released this week, the farmers claim that if they cannot source adequate organic alfalfa, which constitutes a large part of livestock diet, they will not be able to produce organic milk. "Alfalfa is a perennial with a three-mile pollination radius, so farm buffers won't work. It is impossible to contain (…) The USDA cannot ensure GMO alfalfa can be grown without cross-contaminating other crops, so it should not be allowed and it is not needed," they said. The farmers joined the Center for Food Safety (CFS) in its battle against biotech giant Monsanto's GM alfalfa. Last month, CFS won a lawsuit that overturned the US Department of Agriculture's (USDA) approval of the alfalfa variety. US District Court Judge Charles Breyer of the Northern District of California vacated the agency's 2005 approval of the Roundup Ready alfalfa, claiming the agency failed to abide by federal environmental laws when it approved the crop without conducting a full Environment Impact Statement. The judge ordered an immediate halt to sales of the seed, on the grounds that the genetically engineered gene could contaminate organic and conventional alfalfa. Before determining the scope of the final judgment, the court will consider any additional evidence provided. A hearing is scheduled for the end of this month. Alfalfa is grown on over 21 million acres, and is worth $8bn per year (not including the value of final products, such as dairy), making it the country's third most valuable and fourth most widely grown crop. Alfalfa is primarily used in feed for dairy cows and beef cattle, and is also used in pork, lamb, sheep, and honey production. Consumers also eat alfalfa as sprouts in salads and other foods. The nation's organic dairy farmers need approximately 450,000 tons of certified organic alfalfa annually to feed their organic cows. According to Organic Valley farmers, organic feed is already expensive and in short supply, and if organic alfalfa becomes contaminated by GM alfalfa, it would greatly compound the feed shortage. "Contamination of organic alfalfa stands or seed stock will devastate the organic farmers who market milk." "Consumers respect and trust what the USDA organic seal represents, which includes no GMOs. If the seal no longer represents a GMO-free product, the integrity of the seal will be greatly compromised and consumers may no longer choose organic products."