Short answers, pulled from the story.
Animal husbandry is the branch of agriculture concerned with animals raised for meat, fibre, milk, or other products. It covers day-to-day care, management, production, nutrition, selective breeding, and the raising of livestock.
Animal husbandry began around 13,000 BC during the Neolithic Revolution, when animals were first domesticated before the cultivation of the first crops. The dog was the first wild animal to be domesticated.
Robert Bakewell established selective breeding as a scientific practice during the British Agricultural Revolution in the 18th century. He improved the Lincoln Longwool sheep and crossed long-horned heifers with the Westmoreland bull to create the Dishley Longhorn cattle.
Animal husbandry drives climate change, ocean acidification, and biodiversity loss, and kills 60 billion animals annually. It uses between 20 and 33 percent of the world's fresh water and causes up to 91 percent of the deforestation in the Amazon region.
Extensive systems let animals roam at will or under a herdsman, as in ranching across wide grazing lands. Intensive systems keep animals at high density, such as beef cattle in feedlots, pigs in climate-controlled buildings, and laying hens in battery cages.
Pigs and poultry are non-ruminants and cannot digest the cellulose in grass and other forages. They are fed entirely on cereals and other high-energy foodstuffs, with protein from sources such as fish or meat meal and legumes.
Zoonoses are diseases humans may acquire from animals, including rabies, leptospirosis, brucellosis, tuberculosis, and trichinosis. A 1999 Nipah virus outbreak in Malaysia spread from flying foxes to pigs and then to humans, and avian flu H5N1 can pass from poultry to people.