One of the most significant factors involved in calculating how much water is used for beef, pork and poultry production is the type of feed grain used, according to a UC Davis animal scientist. "The amount of water actually used in meat production is sensitive to the proportion of irrigated grain," says James W. Oltjen. For example, most edible beef (about 75 percent) comes from grain-fed cattle. Oltjen estimates that if half the grain the animal consumed were irrigated, it would require 390 gallons to produce one pound of beef. That figure would drop to 105 gallons if the grain were all non-irrigated and would shoot up to 675 gallons if it were all irrigated. A similar trend can be observed in pork and poultry. "It is unknown whether a higher proportion of irrigated grain is used for swine and poultry than for beef," Oltjen says. He presented these findings to the recent American Society of Animal Science at the University of Wyoming.