Animal by-products (ABP) are an important and potentially valuable aspect of the livestock food production chain and are described in many parts of the world as the “Fifth Quarter”.
This description relates to the fact that many animals slaughtered for food (meat) are split into four quarters as part of the butchery process. The fifth quarter is an attempt to describe those parts of the animal that are not directly consumed by humans as food. More accurately these materials are termed animal by-products or ABP for short.