Animals are a part of many agricultural systems. Domesticated animals such as livestock play a critical role in diversified farming systems, both because they or their products become food and because they cycle nutrients through the farm. Wild animals can help to manage pest populations and contribute to biodiversity.
Livestock animals, such as cows, sheep, goats and chickens, have many roles in the farm ecosystem. They eat corn and hay grown on the farm, they provide milk, eggs, wool and meat for humans, and their waste can fertilize the soil. Animal manure contains many nutrients that plants can use to grow. Some farmers collect the manure generated in their barns and spread it on their fields. Animal waste can also be a problem, however. Bacteria in manure can cause diseases. If livestock are near streams, their waste may enter the water that other animals (including humans) may want to drink.
