Proteins

Animal by-products

Poor

Description

Undefined animal parts (bones, organs, feathers...).

Benefits

Inexpensive protein source

Risks

Highly variable quality, no traceability, may include beaks, feathers

Why this ingredient is used

Animal by-products is a legal industry term for everything left over after human butchering: lungs, spleens, stomachs, intestines, beaks, feet, feathers, bones, blood, fat, and trimmings. In theory, some of these cuts are highly nutritious (liver, heart, kidney all beat muscle meat on vitamin density). In practice, the term is used in pet food labels because it lets manufacturers buy the cheapest rendered fraction on the commodity market without committing to any specific quality or species.

Controversies and what to watch for

The problem is traceability, not nutrition per se. When a label says animal by-products with no species specified, the composition can change week to week based on which rendering plant gave the best price. One batch might be 60 percent pork offal, the next 70 percent chicken feather meal, the next mixed poultry intestines. Your pet is eating a different recipe every few weeks without the label changing. In 2007, the melamine scandal showed the risk: thousands of pets in the US died because Chinese exported rendered protein was contaminated with melamine to fake nitrogen (protein) content. PetFoodRate automatically downgrades any product that uses this term.