As the global climate continues to warm, producers may consider cattle selection as a tool to improve climate adaptivity and resiliency. There are two domesticated cattle species that have evolved from wild aurochs (Bos primigenius), European cattle (Bos taurus) and Zebu or Indian cattle (Bos indicus). Selection of Bos indicus cattle species for improved climate adaptivity is not a new phenomenon, and has been discussed in detail, especially regarding the unique characteristics that improve the species’ ability to withstand instances of thermal stress (Lamy et al., 2012; Hansen, 2004; Beatty et al., 2006; Berman, 2011; Gaughan et al., 2018; Terry et al., 2021).
Figure 1. Domesticated cattle species

Bos indicus cattle exhibit, loose skin appendages, large ears, and a cervo-thoracic hump which function to increase an animal’s surface area per unit body weight to aid with heat dissipation, which are not characteristics exhibited by Bos taurus cattle. The hump that Bos indicus cattle possess also allows for localized fat deposition which decreases internal body fat insulation, resulting in increased capacity for heat dissipation. Moreover, Bos indicus cattle also have a greater ability to produce sweat when compared to Bos taurus cattle (Allen, 1962; Allen et al.; 1963, Gaughan et al.; 1999). It has been reported that Bos indicus cattle have a higher density of larger and more superficially located sweat glands, which increases sweat production and allows Bos indicus cattle to dissipate more heat through sweating when compared to Bos taurus cattle (Ney and Heyman, 1956; Dowling, 1955; Pan, 1963). Furthermore, Bos indicus cattle tend to be lighter in color, sleeker, and shinier in contrast to the darker, denser, and typically wooly hide of Bos taurus cattle. The difference in the hide between Bos indicus and Bos taurus cattle alters the external insulation between the animal and the environment.
When considering selection of cattle with a greater adaptive capacity to a warming climate, it is also important to holistically consider economic, environmental, and social implications of these selection decisions. When comparing the species, observations have reported that Bos taurus steers generally have greater feed intake and rate of gain, requiring less days on feed, when compared to Bos indicus steers (Boyles and Riley, 1991; Ferrell and Jenkins, 1998; Adams et al., 1982). When assessing carcass characteristics, Bos taurus steers have been observed to yield greater marbling scores which corresponds to more favorable carcass quality when compared to Bos indicus steers (Ferrell and Jenkins, 1998). The notable meat quality difference between these species could be problematic in a demand-driven industry, such as the United States (U.S.) beef industry that demands superior quality and consistency. Temperament may also be an important consideration for the incorporation of Bos indicus cattle into the U.S. beef industry for multiple reasons. Bos indicus cattle have been observed to be more excitable, and more docile animals may be preferred due to concerns of handler safety, facility wear, and animal welfare (Voisinet et al., 1997). All in all, future research should consider these above-described tradeoffs to account for economic, environmental, and social implications of cattle selection decisions when selecting for climate adaptivity in the U.S. beef industry.

Ashley Schilling-Hazlett
Doctoral Student

Kim Stackhouse-Lawson
Director

Pedro Carvalho
Assistant Professor and Feedlot Specialist