Explain how the intensive rearing of domestic livestock increases net productivity

Productive animals are selectively bred to ensure the next offspring will be equally, if not more productive. These young animals are kept inside in warm conditions to limit energy loss due to maintaining body temperature, and are kept in cramp conditions to limit energy loss due to movement. They are also fed a concentrated and controlled diet, to maximise the amount of food used to create biomass. They are eventually slaughtered before maturity to ensure the maximum energy has been transfered into biomass.