**1. Introduction**

It has been estimated that cattle production in tropical regions accounts for just over half of the cattle worldwide, equating to greater than 805 M head [1]. For such a significant source of beef, the volume of meat-related scientific literature actually undertaken in the Tropics is relatively modest, with most works focused primarily on animal production. Some of this animal science literature uses the terms "tropical beef" or "tropical cattle" to describe cattle raised in and/or adapted to tropical environments [2–7]. However, given that there is much geographic, cultural and economic variation in these environments, it is not surprising that this research varies widely in all aspects of animal production. Regardless, the undefined global terms of "tropical beef" and "tropical cattle" are often cited as descriptors in distinct studies. Yet, while there are commonalities among studies, it has not been demonstrated that sufficient similarities in the cattle exist to describe tropical cattle and, even less so, to characterize the meat from these animals.

The Tropics are the region of Earth surrounding the equator delimited at ±23.5 degrees in latitude by the Tropic of Cancer to the north and the Tropic of Capricorn to the south. The region constitutes 36% of the Earth's landmass and includes more than 130 countries

**Citation:** Rubio Lozano, M.S.; Ngapo, T.M.; Huerta-Leidenz, N. Tropical Beef: Is There an Axiomatic Basis to Define the Concept? *Foods* **2021**, *10*, 1025. https://doi.org/ 10.3390/foods10051025

Academic Editor: Andrea Garmyn

Received: 12 April 2021 Accepted: 29 April 2021 Published: 9 May 2021

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from Africa, America, Asia and Oceania, either wholly or partially [8,9]. According to the Köppen classification, there are three categories of tropical climates based on rainfall dynamics and an average annual temperature always above 18 ◦C: (a) wet equatorial climate (rainforest), (b) tropical monsoon and trade–wind littoral climate (monsoon), and (c) tropical wet–dry climate (savannah) [10,11].

By 2050, global meat consumption is expected to increase by 30% and at least 70% of the increase in beef production required to meet the growing demand is expected to come from the tropical and subtropical regions of the world [12]. Unless there are major changes in production systems, environmental conditions will always determine the types of livestock that can be used in the harsh tropical regions, even though these types may not necessarily meet the growing demand for meat and milk [13]. However, it is not only the climate that dictates animal production in many of these countries. In 2020, the United Nations estimated that some 43% of the world's population, almost 3.8 billion people, live in the Tropics [9]. Of these, about 99% live in a nation considered to be "developing", which includes 85% of the poorest people in the world. People living in the Tropics are also far more culturally diverse than in the rest of the world, exemplified by the fact that these regions account for more than 80% of all living languages [14].

These climatic, cultural and economic conditions have driven production systems in the Tropics to concord in the use of breeds (generally, *Bos indicus* and *Bos indicus* crosses), managemen<sup>t</sup> systems (extensive and semi-intensive) and feed (pastures and finishing grain) and, consequently, produce carcasses of similar quality [15,16]. However, although similar, each region represents an important source of variation to provide meat that is acceptable to the consumer and is culturally and traditionally relevant [17]. These animals are often dual- (milk and meat) or multi-purpose (milk, beef, draught, fuel and fertilizer) and have important functions ranging from the provision of food and income to socioeconomic, cultural and ecological roles of farming communities [18,19]. Tropical cattle production systems make an important contribution to household food security and income for smallholder beef production. However, the majority of the tropical cattle populations remain largely uncharacterized, and the meat quality of these populations is even less explored.

The aim of this review is to investigate the quality and composition of meat from cattle raised in the Tropics to determine if there is an axiomatic basis that would allow the definition of the concept of "tropical beef", where beef refers to the meat and not the animal. Literature cited in the present review was gathered through a range of databases, including, but not exclusively, Scopus, Food Science and Technology abstracts, Agricola, Biological abstracts, CAB abstracts and OVID medline, as well as extended library and online searches for texts on cattle raised in the Tropics. Keywords used included, but were not limited to, variations of Tropics, beef, cattle, breeds, *Bos indicus*, zebu, sanga, Criollo, meat, quality, nutrition, nutrient, composition, carcass, fatty acids, intramuscular fat, minerals, eating quality, tenderness, feedlot, pasture and production systems. The references from the articles obtained by this method were used to identify additional relevant material.

### **2. Cattle Production in the Tropics**

It is inherent that, in order to define a concept of "tropical beef", characterization of the cattle from which the meat is derived is first required. Reviewing similarities and differences between cattle production systems in the Tropics allows a description of tropical cattle and provides context in defining the resulting beef, given that almost all aspects of animal production impact meat quality and nutrient composition to some degree. The importance of a holistic approach to understanding tropical beef quality and composition is exemplified in the description of the strong growth of Brazilian cattle production described by Ferraz and de Felício [20] as being based on a triploid of Nellore-cerrado-*Brachiaria* grass (that is, breed-environment and production system-feed) since 1970. A large body of scientific work reports on genetics and production of cattle in tropical environments. It is beyond the scope of this study to review these aspects, but rather, the focus of this section is to provide context in order to define and understand the characteristics of the meat obtained from "tropical cattle".
