Intensive livestock production systems are those that use higher amounts of labor and capital relative to the land area. The best-known examples are Concentrated Animal Feeding Operations (CAFOs) which house large numbers of animals in small spaces. These operations are dependent on food that was likely produced thousands of kilometers/miles away which increases demand for fossil fuels. They also create large amounts of concentrated waste, CO2 and methane which is damaging to the environment and cannot be reintegrated into the ecological system of a farm because of the monoculture nature of these types of production systems.
In contrast, extensive farming systems are dependent on the carrying capacity (soil fertility, terrain, water availability, etc.) of a given piece of land and often responds to the natural climate patterns of an area. It does not depend on a large amount of pesticides, fertilizers or other chemical inputs relative to the land area being farmed. This is how most livestock production takes place int he world. Herders are the classic example.
The main difference between the two types of agriculture is that extensive agriculture requires much more land for production and profitability than intensive production. As such, extensive agriculture is often practiced where population densities are low and land is inexpensive.
The danger of intensive agriculture, apart from environmental degradation and animal welfare issues, is that prices can be depressed by overproduction when extensive tracts of land are used for production – despite the intense nature of agricultural practices. Low prices do not reflect the actual price of food production and can result in poor market results. It can also be argued that because of the extremely low price of food, it is a commodity that is taken for granted and often wasted – especially in the western world.