UC Davis

Updating the static model by Beckett and Oltjen (1993), we determined that from 1991 to 2019, U.S. beef cattle blue water consumption per kg of beef decreased by 37.6%. Total water use for the U.S. cattle herd decreased by 29%. As with the 1993 model, blue water use included direct water intake by animals, water applied for irrigation of crops that were consumed by beef cattle, water applied to irrigated pasture, and water used to process animals at marketing. Numbers of cattle, crop production, and irrigation data were used from USDA census and survey data. On 1 January 2019, a total of 31.7-million beef cows and 5.8-million replacement heifers were in U.S. breeding herds, and 26-million animals were fed annually. In total, the U.S. beef cattle herd (feedlot and cull cows) produced 7.7-billion kg of boneless beef, an increase of 10% since 1991. Beef cattle directly consumed 599-billion L of water per year. Feedlot cattle were fed various grain and roughage sources corresponding to the regions in which they were fed. Feeds produced in a state were preferentially used by cattle in that state with that state's efficiency; any additional feedstuffs required used water at the national efficiency. Irrigation of crop feedstuffs for feedlot cattle required 5,920-billion L of water. Irrigated pasture for beef cattle production required an additional 4,121-billion L of water. Carcass processing required 91-billion L of water. The model estimated that in the U.S. 2,275 L of blue water was needed to produce 1 kg of boneless meat. As with the previous model, the current model was most sensitive to changes in the dressing percentage and the percentage of boneless yield in carcasses of feedlot cattle (62.8 and 65, respectively). In conclusion, with more beef, fewer cows, and lower rates of irrigation, beef cattle's water intensity has decreased at an annual rate of 1.34% over a 28-yr period.