Table 2

Comparison of the impact of grazing and intensive (confined/industrialized) grain-fed livestock systems on water use, grain requirement, and methane production. Service water is that required for cleaning and washing livestock housing and other facilities. Dashes indicate combinations for which no data are available (either because it cannot be measured or because the combination does not exist). This table does not include other impacts of differing livestock management systems such as (i) nutrient run-off and pollution to surface and groundwater, (ii) protozoan and bacterial contamination of water and food, (iii) antibiotic residues in water and food, (iv) heavy metal from feed in soils and water, (v) odor nuisance from wastes, (vi) inputs used for feed production and lost to the environment, (vii) livestock-related land-use change. [Source: (7, 50)]

WaterMeasure of water useGrazingIntensive
Liters day–1 per animal at 15°C
CattleDrinking water: all22103
Service water: beef511
Service water: dairy522
Pigs (lactating adult)Drinking water1717
Service water25125
Sheep (lactating adult)Drinking water99
Service water55
Chicken (broiler and layer)Drinking water1.3–1.81.3–1.8
Service water0.09–0.150.09–0.15
Feed required to produce 1 kg of meatkg of cereal per animal
Cattle8
Pigs4
Chicken (broiler)1
Methane emissions from cattlekg of CH4 per animal year–1
Cattle: dairy (U.S., Europe)117–128
Cattle: beef, dairy (U.S., Europe)53–60
Cattle: dairy (Africa, India)45–58
Cattle: grazing (Africa, India)27–31