Animal Agriculture Essential to Ensure Adequate Global Food Supply

July 14, 1999

Animal Agriculture Essential to Ensure Adequate Global Food Supply

Projections by CAST Scientists

The Council for Agricultural Science and Technology (CAST), an international consortium of 38 scientific and professional societies, released a report Animal Agriculture and Global Food Supply in which a CAST international task force of 13 scientists discusses projected demand for human food and the importance of animal agriculture in meeting these needs. The task force chaired by Dr. Eric Bradford, Department of Animal Science, University of California, Davis, includes scientists with expertise in agricultural economics, agronomy, animal sciences, environmental issues, international food policy, international livestock research, nutritional science, range science, and veterinary medicine.

Animal Agriculture Is Integral Part of Food-Producing System

Animal agriculture is an integral part of food-producing systems, with foods of animal origin representing about one-sixth of human food energy and one-third of the human food protein on a global basis. Animals

  • convert forages, crop residues, and food and fiber processing by-products to high quality human food;
  • provide draught power for about half the world's crop production;
  • provide manure to help maintain soil fertility;
  • make important contributions to agricultural economies throughout the world; and
  • contribute to food security in developing countries.

Need to Quantify Net Contribution of Animal Production

Animals also consume one-third of the global cereal grain supply. In a world with human population forecast to reach 7.7 billion by the year 2020, a fixed or possibly shrinking quantity of arable land, and an estimated 800 million undernourished people, CAST deemed it prudent to quantify the net contribution of animal production to quantity and quality of the world food supply.

Meat Consumption Projections

Consumption of meat, milk, and eggs varies widely among countries, reflecting differences in food production resources, production systems, income, and cultural factors. Per capita consumption is much higher in developed countries but the current rapid increase in many developing countries is projected to continue. Total meat consumption in developing countries is projected to more than double by the year 2020, while, in developed countries, it is projected to increase no more and, in some cases, less than population growth. Because most of the world's population is in developing countries, which are experiencing the most rapid growth rates, global demand for meat is projected to increase more than 60% of current consumption by 2020.

Value of Animal Food Products in Diet

At low levels of intake of meat and milk, an increase in consumption of these foods is known to be nutritionally beneficial, particularly for young children. These benefits result from the higher content and nutritional availability of essential amino acids and several micronutrients including minerals and vitamins. Thus, if achieved, projected increases in per capita intake of meat and other animal products in developing countries should improve people's nutritional status. In developed countries, on the other hand, intakes of food from animals are higher than justified by nutritional grounds alone. A decrease in intake of these foods to reduce intake of saturated fat and cholesterol has been recommended by some health scientists, but there is continuing debate about the probable benefits to the health of the general population of such a reduction.

Conversion Rates of Grain to Animal Food Products

Conversion rates of the energy and protein in feeds consumed by animals to human food energy and protein vary, depending on species, production system, feed type, and product.

  • Poultry and pork production are most efficient on the basis of total feed intake.
  • But, on average, ruminants (cattle, sheep, goats) return more human food per unit of human-edible feed consumed because most of their feed is materials that cannot be consumed directly by humans.

This fact has been overlooked in some assessments of the role of animals in food production. On a global basis,

  • less than three kilograms of grain are required to produce a kilogram of meat from any of the species and
  • less than one kilogram of grain per kilogram of milk or eggs.

Less grain is fed to livestock in developing than in developed countries. It has been estimated that, on a global basis, animals produce a kilogram of human food protein for each 1.4 kilogram of human-edible protein consumed.

The biological value of protein in foods from animals is about 1.4 times that of foods from plants. Thus, diverting grains from animal production to direct human consumption would, in the long term, result in little increase in total food protein and would decrease average dietary quality and diversity. Also, feed grains can be and are diverted to direct human use during periods of temporary feed grain shortage. An additional consideration is that corn, or maize, the principal feed grain, yields much more per hectare than wheat, the number one food grain.

Improved Conversion Rates of Grain to Animal Food Products

Recently, conversion rates of grains to meat, milk, and eggs have improved significantly in both developed and developing countries. Investing in research for new technologies and applying known technologies to a larger proportion of the world's animal populations offers the potential for substantial additional improvements in efficiency. This suggests that grain requirement per unit of animal food product should decrease. However, the largest increases in demand are forecast for poultry, pork, and aquaculture products, species requiring relatively high human-edible content diets. The net effect on grain demand is, therefore, difficult to predict but it is estimated that an annual rate of growth in cereal production between 1.1 and 1.4%, i.e., a lower rate than in recent decades, should meet needs for both food grains and the feed grains required to meet the projected per capita demand for meat, milk, and eggs.

Environmental Effects of Livestock

Livestock have both positive and negative environmental effects. Improved management of livestock grazing, better management and use of manure, and increased care in design and siting intensive production operations will be necessary to maximize beneficial effects and minimize detrimental effects of livestock. Government policies related to land use and economic development are important in this area.

The Challenge

The CAST task force scientists conclude that meeting projected demand for foods of both plant and animal origin in 2020, while sustaining the productive capacity of the land, will be challenging but feasible. Animal agriculture will continue to be an important part of food-producing systems. Investment in agricultural production research and development and implementation of policies that encourage production, while protecting the environment, will be essential to achieving the goal of an adequate global food supply.

Editor: A free copy of Animal Agriculture and Global Food Supply is available to journalists on request.

Animal Agriculture and Global Food Supply, 92 pages, is available for $30.00 from CAST. CAST identifies food and fiber, environmental, and other agricultural issues and interprets related scientific research information for legislators, regulators, and the media for use in public policy decision making. CAST is a nonprofit organization of 38 scientific societies and many individual, student, company, nonprofit, and associate society members. The CAST World Wide Web site is