Cattle and sheep are the animals that are used the most commonly in feedlots in South Africa and around the world. Although other edible animals are also fed commonly, it is done to promote growth (chickens and pigs) and not to fatten the animal. In some cases, goats may also form part of a fattening unit.
The reason cattle and sheep are used most commonly in feedlots is the fact that these animals have a very good feed transfer ratio (FTR), and it is thus relatively cheap to feed them. The good FTR is due to the fact that these animals are part of the ruminant family which will be explained later. Secondly, it is not always possible to bring these animals up to a market-ready weight on extensive conditions, because the resources in the field may be limited.