Beyond Body Condition Score: A Proposed Interspecies Framework for Tissue-by-Tissue Nutritional Assessment in Veterinary Practice

In clinical veterinary medicine, the Body Condition Score (BCS) serves as a validated, semi-quantitative estimation of subcutaneous adipose reserves, yet it cannot by itself detect systemic nutrient deficiencies or excesses that do not necessarily imply energy storage. Human clinical dietetics addressed an analogous diagnostic gap through the Nutrition-Focused Physical Examination (NFPE), but veterinary medicine still lacks a unified, multi-species physical examination sequence for nutritional screening. This narrative review synthesizes the comparative and clinical nutrition literature into a proposed, operational interspecies framework for nutritional assessment, designed to complement the BCS and the Muscle Condition Score (MCS) within the existing WSAVA and AAHA nutritional assessment guidelines. The approach sequences a detailed feeding and behavioural anamnesis with a systematic, tissue-by-tissue physical examination of the integument, mucous membranes, skeleton, muscle and joints, and endocrine-metabolic status, supported by metabolic and haematological profiling. Seven synoptic diagnostic tables link observable clinical signs to specific micro- and macronutrient imbalances, the underlying nutritional mechanisms, and the species-specific dependence on key nutrients. Key interspecific determinants are integrated to support differential diagnosis and to caution against uncritical cross-species extrapolation. Each clinical entry is explicitly classified as a primary nutrient deficiency or excess, a nutrition-responsive or nutrition-related metabolic disease, a disease causing secondary malnutrition, or a management or behavioural determinant of intake, and each table states the principal non-nutritional differentials and the confirmatory test required, so that the tables function as screening prompts. The resulting semiotic methodology is intended to extend nutritional assessment beyond fatness (assessed on extension of explorable sub-cutaneous adipose tissue) towards whole-body nourishment. It is presented as a proposed framework and not as a validated instrument, and it requires prospective validation before any routine clinical adoption across animal species. The supporting evidence is substantially stronger for dogs, cats, horses, and ruminants than for avian, reptile, and small exotic mammal species, for which the present extension is a proof of concept requiring dedicated species-specific validation.