An apparatus and method for identifying a carcass during meat production. The method for manufacturing a compound semiconductor epitaxial substrate comprises a step of epitaxially growing an InGaAs layer on an InP single crystal substrate or on an epitaxial layer lattice-matched to the InP single crystal substrate under conditions of ratio of V: 10-100, growth temperature: 630\xb0 C. The plurality of light emitting diodes may be positioned a prescribed distance from a point on the mounting surface.