Although published guidelines exist for horse and donkey nutrition, specific guidelines for mules are lacking, and their nutritional needs remain poorly studied. The limited published information on mule nutrition is based on author experience and recommends feeding them like donkeys, with a diet high in fiber and low in energy (Smith DG, Burden FA, Chapter 16: Practical donkey and mule nutrition. In: Geor RJ, Harris PA, Coenen M (eds) Equine applied and clinical nutrition. W.B. Saunders, pp 304–316. https://doi.org/10.1016/B978-0-7020-3422-0.00016-X , 2013; Burden FA, Bell N, Vet Clin N Am Equine Pract 35:469–479, 2019; The Clinical Companion of the Donkey. The Donkey Sanctuary, Leicester, 2021). While this approach is appropriate for some mules, it may oversimplify others metabolic and nutritional needs by overlooking the influence of environmental and maternal factors. Further, as with horses and donkeys, the development of a nutrition program for mules should account for individual energy needs based on growth, level of work, and metabolic status. For instance, growing mules or those engaged in intense work need more energy, protein, and water than mature, companion, or lightly worked mules.