Animal husbandry in the British Agricultural Revolution of the 18th century, when livestock breeds like the Dishley Longhorn cattle and Lincoln Longwool sheep were rapidly improved by agriculturalists such as Robert Bakewell to yield more meat, milk, and wool. A wide range of other species such as horse, water buffalo, llama, rabbit and guinea pig are used as livestock in some parts of the world. Insect farming, as well as aquaculture of fish, molluscs, and crustaceans, is widespread. Modern animal husbandry relies on production systems adapted to the type of land available. Subsistence farming is being superseded by intensive animal farming in
Animal genetic resources for food and agriculture assessments of livestock biodiversity: "The State of the World's Animal Genetic Resources for Food and Agriculture" (2007) and "The Second Report on the State of the World's Animal Genetic Resources for Food and Agriculture" (2015). Although many diverse species and breeds of animals are currently available for food and agricultural production, there is more work to be done on classifying their risk of extinction: in 2014, 17% of the world's farm animal breeds are at risk of extinction and 58% are of unknown risk status, meaning that the problem may be underestimated. The world's pool of animal genetic resources is