Evaluation of Long Bone Marrow Composition of Roe Deer (Capreolus capreolus)

Assessing body condition in mammals is essential to understanding their nutritional status and health. Traditionally, fat content in femur bone marrow has been used as an indicator, but this study aims to improve assessment by expanding analysis to multiple long bones of roe deer (Capreolus capreolus) in the Alps. Marrow samples were collected from 14 animals, with 25 femur samples analyzed for dry matter (DM), ether extract (EE), and color, the latter measured objectively using RGB values. The main innovation is the use of objective color quantification of marrow as a non-destructive proxy for fat content, showing strong correlations with DM and EE. Results reveal significant correlations between femur EE and tibia DM, as well as between femur and humerus DM, indicating consistent fat distribution across the analyzed bones. Metacarpus and metatarsus bones showed weaker correlations. This method represents a preliminary validation, especially for wildlife studies where full carcasses are often unavailable. The approach based on objective marrow color analysis improves reproducibility and standardization in body condition assessment, enhancing comparability across ecological and zoological studies worldwide.