Tankage

Tankage is the solid byproduct of the rendering of animal materials, specifically the non-fat portion remaining after fats are extracted from slaughterhouse byproducts such as offal, bones, and blood. The material is produced by heating and pressing the tissue to separate fat, followed by drying and grinding the residue into a meal or coarse powder. The name reflects its historical collection in storage tanks during processing.

Tankage is characterized by high protein content and mineral matter, with little or no fat. Protein levels vary with the source material and processing, and ash and moisture contents can also be significant. Because it is a heterogeneous byproduct, the quality and digestibility of tankage ranges widely.

Historically, tankage was used as an inexpensive protein supplement for livestock feeds, particularly in pig and poultry rations, and in some regions as a fertilizer or soil conditioner. Over time, its use in feed has declined in many markets due to volatility in raw-material supply, competition from more uniform feed ingredients, and regulatory restrictions related to animal-byproduct proteins.

Regulatory oversight exists to ensure safety and labeling. In many jurisdictions, feeding mammalian proteins to ruminants is restricted to prevent disease transmission, and tankage products are subject to standard feed-safety and quality controls. Modern equivalents include meat meal and meat-and-bone meal, which have largely replaced traditional tankage in commercial feeds, though the term may remain in historical reference or in regional practices.