Nutritional evaluation in wildlife species under human care allows identifying nutritional deficiencies and contributes to the improvement of health; economic analysis makes it possible to evaluate the financial sustainability of the system. We compared two alimentary systems in Animal Management Units for Wildlife Conservation of white-tailed deer (Odocoileus virginianus), using a nutritional diagnostic approach and economic analysis. The study was carried out in UMAs Sierra Morelos and the Ocotal, located in the State of Mexico. We determined crude protein (PC), ether extract, neutral detergent fibers, Ca, and P levels of the two diets. To estimate the energy–protein balance, we determined apparent digestibility of dry matter (ADDM), the metabolizable energy (ME), the net energy for maintenance (NEm), and the metabolizable protein (MP), establishing which system ensured better animal growth. The total and diary costs of the two systems were compared to determine the optimal economic return. Both diets were similar in terms of nutrients and energy, and no statistically significant changes in corporal condition between treatments were found. The Sierra Morelos system showed lower economic expenses, with feeding costs being 50% lower than those of the Ocotal system.