This test method is a modified version of the standard ether extraction method for determining crude fat in animal feed and feed ingredients. This modification is used when samples contain bound fats (e.g., in high-fiber or heat-processed feeds) that are not fully extractable by ether alone. The sample is first treated with hydrochloric acid (HCl) and heated to break down protein-fat and carbohydrate-fat complexes, releasing bound lipids. The hydrolyzed mixture is extracted with ether solvents, and the solvent-extracted fats are collected. The solvents are evaporated, and the fat residue is dried and weighed.