Farm animals supply an estimated thirty percent of all food and agricultural needs. They provide products like milk, meat and eggs. They provide fertilizer to help crops grow. And they help farmers work the land.

But there is concern about the loss of many kinds of farm animals as a result of efforts to create new ones. People began to breed livestock at least twelve thousand years ago. Animals not only provided food and labor. Their skin and bones also provided clothes and tools. But people also bred animals to survive local conditions.

Breeders look for farm animals with desirable qualities. Such animals are then used to reproduce, so they pass along these qualities for the future. Competition becomes difficult for animals with qualities that are seen as less desirable. The United Nations Food and Agriculture Organization says more than eight hundred breeds are in danger.

Big farms and modern agriculture often depend on only a few kinds of livestock. These animals have been bred to meet the needs of new technology and production methods.

But older kinds of farm animals can be useful too. They may not be as productive as newer kinds of livestock. Yet, they may remain productive even under severe conditions. The Jamunapari goat of India, for example, produces good milk and meat. But its ability to survive in dry conditions with little food makes it highly valuable in parts of India.

The Taihu pig of China is another example. It does not produce as much meat as some breeds of pig. But, it is able to eat many kinds of food and reproduce more than Western breeds.

The Food and Agriculture Organization publishes a list of farm animals that are in danger of disappearing. The agency calls it the World Watch List for Domestic Animal Diversity. The F.A.O. is leading an effort to collect genetic information from breeds of farm animals around the world. In the United States, the American Livestock Breeds Conservancy gathers information on rare farm animals and seeks to protect them.

Breeding over thousands of years has created genetic diversity among farm animals. Different genes can give animals the ability to survive under more conditions. It can also give them better resistance to disease. But now experts warn that we are losing that genetic diversity. At least four thousand breeds of farm animals have been developed. But some experts say hundreds of breeds have disappeared.

This VOA Special English Agriculture Report was written by Mario Ritter. This is Steve Ember.