Fur, Feathers, and Fins - Animals in our food
Module III > Section C > Activities

Activities for Module III Fur, Feathers, and Fins - Animals in our food

Activities for Section C: Animals in the Agro-ecosystem


Activity 1: Water and Numbers

Part 1. How much water does it take to produce a pound of beef?
Part 2. How much water do you use at home?
Part 3. Concluding discussion

Purpose: Students will explore the impacts of animal agriculture on water, consider regional differences in water use, and begin thinking critically about statistics.

Advance preparation:

Part 1. Print out the Part 1 handout. Make enough copies for all the small groups.

Part 2. Print out the chart for estimating water use from National Geographic water use calculator and make copies. Ask students to bring in copies of their water bills if they are on public water supply.

Part 3. Print out “Water Facts and Figures”

Estimated time: Part 1: 20 minutes, Part 2: 30 minutes, Part 3 (concluding discussion): 15 minutes

Background information: One common criticism of meat production is that it uses a lot of water compared to other agricultural products.

Estimates of how much water meat production takes vary widely, but even conservative estimates make beef a pretty water-intensive food.

Part 1: How much water does it take to produce a pound of beef?

Divide the students into small groups. Give each group the three water use estimates. Have each group discuss and answer the questions in this worksheet (MS Word document).

Key to discussion questions in above worksheet link:

  1. Which calculation do you think is the right one?

    All three estimates may be roughly valid, since they are measuring different things. It depends on how they are used.
  2. What difference does it make whether the water to grow the feed comes from rainfall or irrigation?

    If the water comes directly from rainfall, then how it acts in the environment is not changed that much by the fact it is helping food for cattle to grow, especially if the food is well managed pasture, not treated with fertilizers or pesticides. If the water is irrigation water, then its use will have much greater environmental impacts.

    Much of the forage and grain fed to beef produced in the western US is grown using irrigation. Some of this irrigation water is pumped from aquifers at unsustainable rates. Some is diverted from river systems, altering aquatic communities and reducing the water available for other uses. For example about 85% of the water taken from the Colorado River in California, Arizona, and Nevada is used for agricultural purposes. Long before the Colorado River reaches its historic outlet to the ocean in Mexico, it has completely dried up, because its natural flow has been diverted for agricultural use. Some of the water withdrawn goes to fruit and vegetable production, but livestock production is a major water user (see Land Use History of North America)

    In Wisconsin and Iowa, in most years rainfall is adequate for forage production, and very few farmers irrigate pastures, hayfields, or feed crops. However, farmers do withdraw water from streams and wells to provide drinking water for their animals, as well as water for washing milkrooms and other animal production facilities. This agricultural use can have impacts on some local water supplies or aquatic systems.

  3. Does it matter how the irrigation is handled? Why and how?

    How the irrigation is handled matters a lot. For the environment it matters how much water is withdrawn from natural water courses and how efficiently the water is used. For example, if half the water is lost in transport (not uncommon), then actually double the amount of water used for irrigation had to be taken away from a river or stream. If the irrigation water is applied in the same small watershed that it was taken from, at least some of it will be returned to the river or stream. If it is applied in a different watershed, all the water is lost to the original water source. It also matters for social reasons. For example if upstream users take all the water they want, there may be none left for downstream users.
  4. Why do you think the Cattlemen’s association publicizes the figure of 435 gallons? Why do many environmental organizations use the higher figure estimated by Pimentel? Why does it matter how much water it takes to produce a pound of beef?

    The National Cattlemen’s Beef Association wants people to think that beef production is environmentally benign, so they choose the lowest estimate. In addition, the association may wish to protect certain regional interests. Using a national average obscures the differences in environmental impact caused both by geography and by the production system.

    Environmental organizations want people to realize how high the environmental costs of beef production can be, so they use the higher figure. Unfortunately, by doing so, they imply that all beef production has a level of environmental impact that in fact only some producers have.

    The amount of water used in beef production is important when it has negative impacts on the environment or on access to water for other uses. Of course, livestock production can damage the environment in other ways than water use.

  5. These estimates were all calculated at least ten years ago. Do you think water requirements for beef production have changed? Why or why not?

    Since there are no newer estimates, we can’t be sure whether or how water use for beef production has changed. However, it is likely that it has not changed much, if at all. Agriculture’s use of water for irrigation has been fairly stable over the last 10 years, though there are some annual fluctuations due to weather. While there have been some improvements in irrigation technology, there has also been an increase in the acreage under irrigation, perhaps due to climate change. (See USGS estimates)

Part 2: How much water do you use at home?

The purpose of this part of the activity is two-fold: First, students will get a sense of household use of water, which they can then compare to agricultural water use, and especially that needed for beef production. Second, students will realize how difficult it is to estimate water use, and how much use varies.

Have students use the water bill information  to compute average weekly household use. (Take  number of days covered by billing period and divide  by 7 to get the number of weeks in the billing period. Then take the figure for total water use and divide that by the number of weeks in the  billing period.) Compare the information on the water bills with the students' estimates  from the water use charts.

Note that the estimated amounts on the chart make assumptions about the efficiency of appliances and about how people use them. If students have better information about their own household appliances, they can use the more accurate information.

Have students use the water bill information to compute average weekly household use. (Take number of days covered by billing period and divide by 7 to get the number of weeks in the billing period. Then take the figure for total water use and divide that by the number of weeks in the billing period.) Compare the information on the water bills with the students’ estimates from the water use charts.

The Down the Drain Project personal water use chart provides guidance for estimating your water use and comparing it to other students, mostly in the US.

Part 3. Concluding discussion

Share the water facts and figures with the students. Discuss the questions from Part 1 of this activity with the class, along with the questions below, in light of what students learned from doing their own water use assessment and in light of the information in the water facts and figures.

How does use of water for beef production compare with other food production? With other consumer products?

Even using a more conservative estimate, beef is an intensive water user compared to other foods. However, where and how the beef is raised can make an important difference in how much water it uses.

Although industry uses water too, agriculture accounts for more use, and unlike industry, most agricultural use is not returned to the same watercourse.

What can we learn about numbers and statistics from this exercise?

First, it is not easy to generate accurate statistics. Second, averages obscure significant variations. Third, it is important to know what assumptions were made in generating a number in order to know how that number should be used.

How could you design a beef production system that would have relatively little impact on water supplies?

A system that relies on non-irrigated pasture and feed will have comparatively little impact on water in the environment and water supplies.

Water Facts and Figures

According to the American Water Works Association:
The average US household uses about 127,000 gals water / year. About 40% or 50,800 gals are used indoors. The rest is used outdoors. The average US individual uses around 100 to 180 gallons per day. (Average use tends to be higher in dry areas, mainly because of landscape watering.)

  • In households not utilizing water-efficient fixtures, toilets used the most water on a daily basis (20.1 gallons per person per day). Clothes washers were the second largest water users (15 gallons per person per day) and showers were third (13.3 gallons per person day).
  • In households that utilized water-efficient fixtures, clothes washers assume the role of top water user (15 gallons per capita per day), followed by faucets (10.9 gallons per capita per day), showers (10 gallons per capita per day) and toilets (9.6 gallons per capita per day). NOTE: The REUWS study group did not contain a significant number of homes with water conserving clothes washers.

How is Most Freshwater in the US Used?

In 2000, about 346,000 million gallons per day of fresh water was withdrawn from our surface- and ground-water sources, such as rivers, lakes, reservoirs, and wells. Two uses, irrigation and thermoelectric-power production, accounted for about 79 percent of water used in 2000. Here's the breakdown by water-use category:

  • Irrigation: 40 percent
  • Thermoelectric power: 39 percent
  • Public Supply: 13 percent
  • Industry: 5 percent
  • Livestock, aquaculture: less than 1 percent
  • Domestic (self-supplied): 1 percent
  • Mining: 1 percent

The large amount of water used for power production (electricity) is mostly used to cool the heated power-production equipment. The vast majority of the water used by power plants is returned to the environment, and thus is available for other uses. In contrast, irrigation water is not available for other uses.

In Wisconsin, however, the breakdown of water use is a little different:

  • Thermoelectric: 79 percent
  • Industrial: 8 percent
  • Domestic: 4 percent
  • Agricultural Irrigation: 3 percent
  • Public Use: 2 percent
  • Non-irrigation Agriculture: 2 percent
  • Commercial: 2 percent

    (Source: Implementing the Great Lakes Compact: Wisconsin Conservation and Efficiency Measures Report, UW-Madison Dept. of Urban and Regional Planning, p. 4, accessed March 2010 at http://urpl.wisc.edu/people/genskow/URPLconservationefficiency2009.pdf )

(US Geological Survey)

The average American individual uses 80 to 100 gallons of water at home each day.
The average individual from Uganda or Ethiopia uses less than 5 gallons of water each day
(statistics taken from U.S. Geological Survey water facts website and page 34 of the 2006 UN Human Development Report Beyond scarcity: Power, poverty, and the global water crisis."

Water required to produce one pound (lb.) of California foods:

  • 1 lb. lettuce: 23 gallons
  • 1 lb. tomatoes: 24 gallons
  • 1 lb. wheat: 25 gallon
  • 1 lb. carrots: 33 gallons
  • 1 lb. apples: 49 gallons
  • 1 lb. chicken: 815 gallons
  • 1 lb. pork: 1,630 gallons
  • 1 lb. beef: 5,214 gallons

(according to Soil and Water specialists, Univ. of Calif. Agricultural Extension, working with livestock farm advisors Schulbach, Herb , et. al., Soil and Water, No. 38, Fall 1978, retrieved from Food Revolution.

Water quotes:

"The conclusion of a 2000 report by the World Commission on Water predicts that the increase in water use in the future due to rising population numbers will 'impose intolerable stresses on the environment, leading not only to a loss of biodiversity (species extinction), but also to a vicious circle in which the stresses on the ecosystem (will) no longer provide the services for plants and people." ("A Water Secure World: Vision for Water, Life, and the Environment," Reported in Mittelstaedt, Martin, "World Water Use to Soar to Crisis Levels, Study Says," The Globe and Mail, March 14, 2000)

"In California, the single biggest consumer of water is not Los Angeles. It is not the oil and chemicals or defense industries. Nor is it the fields of grapes and tomatoes. It is irrigated pasture: grass grown in a near-desert climate for cows... The West's water crisis --- and many of its environmental problems as well --- can be summed up, implausible as this may seem, in a single word: livestock."
(From Cadillac Desert by Marc Reisner)

"Nearly half the water consumed in this country is used for livestock, mostly cattle."
(Audubon Magazine, Dec. 1999)

Activity 2. Ecological pawprint analysis

Purpose: Students will apply the ecosystem concepts they have learned to animals in their own lives. .

Advance preparation:

Estimated time: 15 to 20 minutes

Place students in small groups, making sure each group includes at least one student who has one or more pets. Use the four agro-ecosystem questions to evaluate the ecological impact of their pets:

Where do key nutrients come from?

What does the pet eat? Where does the food come from? What happens to the pet’s waste?

What are the sources and sinks of pollutants in this system?

Does the pet cause pollution? What is the cumulative impact of dog and cat feces in this community? What about in different types of communities (urban, rural)? What is the recommended method of disposal of pet wastes? What are the impacts of this method of disposal? What about pest management, medications, and grooming products for your pet? Do these products get into the environment?

How do the living organisms in the system interact?

How does the pet affect diversity? Does it hunt? Do escapees of its kind hunt or displace native species? How was it bred? (Some exotic fish, reptiles, and birds are caught in the wild and such exotic pet trade can put added pressure on rare species.) See http://www.emagazine.com/septemberoctober_2003/0903curr_feral.html

What are the energy flows?

Does the pet require extra consumption of fossil fuel? (Think about producing, processing, and transporting its food, waste disposal, transportation costs for large animals such as horses, heating costs, etc.)

Have students discuss possible ways the ecology of pet management could be improved.

*Note that the Animal Protection Institute report on pet foods suggests that using processed slaughterhouse waste for pet food is a bad thing. However, from a nutrient cycling point of view, it is better than disposing of those wastes in a landfill and using premium meats to feed pets. Also, unprocessed meat would require refrigeration, using more fossil fuels.

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