In recent years, some organizations have also raised livestock to promote the survival of rare breeds. The breeding, maintenance, and slaughter of these animals, known as animal husbandry, is a component of modern agriculture that has been practiced in many cultures since humanity's transition to farming from hunter-gatherer lifestyles.
Animal husbandry practices have varied widely across cultures and time periods. Originally, livestock were not confined by fences or enclosures, but these practices have largely shifted to intensive animal farming, sometimes referred to as "factory farming". Now, over 99% of livestock are raised on factory farms. These practices increase yield of the various commercial outputs, but have also led to negative impacts on animal welfare and the environment. Livestock production continues to play a major economic and cultural role in numerous rural communities.
Livestock as a word was first used between 1650 and 1660, as a merger between the words "live" and "stock". In some periods, "cattle" and "livestock" have been used interchangeably. Today, the modern meaning of cattle is domesticated bovines, while livestock has a wider sense.
United States federal legislation defines the term to make specified agricultural commodities eligible or ineligible for a program or activity. For example, the Livestock Mandatory Reporting Act of 1999 (P.L. 106-78, Title IX) defines livestock only as cattle, swine, and sheep, while the 1988 disaster assistance legislation defined the term as "cattle, sheep, goats, swine, poultry (including egg-producing poultry), equine animals used for food or in the production of food, fish used for food, and other animals designated by the Secretary."
Deadstock is defined in contradistinction to livestock as "animals that have died before slaughter, sometimes from illness". It is illegal in many countries, such as Canada, to sell or process meat from dead animals for human consumption.