Small Ruminant Production Based on Rangelands to Optimize Animal Nutrition and Health: Building an Interdisciplinary Approach to Evaluate Nutraceutical Plants

SIMPLE SUMMARY: The low deciduous forest is an ecosystem covering 8% of México’s surface and is present in 15 of the 32 states of the country. It has been observed that sheep and goats feeding in this high biodiverse biome can consume up to 80 plant species. In addition, the low deciduous forest biomass is frequently used to feed small ruminants in cut and carry systems. However, there is not enough information to provide guidelines for its sustainable use by ruminant livestock. In the present review, we present an interdisciplinary approach aimed at identifying the nutraceutical properties of this native vegetation system, involving disciplines like botany, ecology, agronomy, ethology, ethnoveterinary, nutrition, parasitology and chemistry. Nutraceuticals are defined as livestock feeds combining nutritional value with beneficial effects on animal health and productivity. The identification of nutraceutical properties amongst plant species of the low deciduous forest may contribute to the revalorization of this native vegetation system and provide information enabling the design of sustainable livestock feeding/management systems that benefit the nutrition and health of small ruminants, and ultimately human health through the consumption of animal products produced in this native vegetation system. ABSTRACT: The plant kingdom can influence the productivity and health of herbivores at different levels. However, demonstrating this process in a scientific manner entails substantial endeavors from different disciplines. In the present review, we will describe the features of a native vegetation system traditionally used by small ruminants and use its particularities to build an interdisciplinary approach to evaluate the nutraceutical properties of plants. Initially, we will establish the context of the low deciduous forest (LDF), considering some botanical and nutritional aspects, as well as the presence of plant secondary compounds (PSC) and gastrointestinal nematodes (GIN). Furthermore, we will focus on coevolutionary aspects that undoubtedly shaped the plants–nutrients–PSC–GIN–herbivore relationship. In addition, the concept of nutraceutical will be discussed to provide clarity and aspects to be considered for their evaluation. Then, ethological, agronomical, nutritional, PSC, parasitological and animal species issues are deepened placing emphasis on methodological approaches. Special focus is given to condensed tannins, as they are the fourth largest group of PSCs and the most studied in livestock sciences. Validation of the nutraceutical properties of plants from native vegetation systems should be seen as a process derived from many scientific disciplines that feed into each other in a cyclic manner.