Evolutionary process of Bos taurus cattle in favourable versus unfavourable environments and its implications for genetic selection

Abstract

The evolutionary processes that have enabled Bos taurus cattle to establish around the globe are at the core to the future success of livestock production. Our study focuses on the history of cattle domestication including the last 60 years of B. taurus breeding programmes in both favourable and unfavourable environments and its consequences on evolution and fitness of cattle. We discuss the emergence of 'production diseases' in temperate production systems and consider the evolutionary genetics of tropical adaptation in cattle and conclude that the Senepol, N'Dama, Adaptaur and Criollo breeds, among others with similar evolutionary trajectories, would possess genes capable of improving the productivity of cattle in challenging environments. Using our own experimental evidence from northern Australia, we review the evolution of the Adaptaur cattle breed which has become resistant to cattle tick. We emphasize that the knowledge of interactions between genotype, environment and management in the livestock systems will be required to generate genotypes for efficient livestock production that are both economically and environmentally sustainable. Livestock producers in the 21st century will have less reliance on infrastructure and veterinary products to alleviate environmental stress and more on the animal's ability to achieve fitness in a given production environment.

Keywords: adaptation; breeding; cattle; environment; genetic improvement; trait.

Figure 1

Arithmetic means (three highest counts for the calf crop) (±SEM) of field tick (Rhipicephalus microplus) infestations of heifer progeny of Brahman and Adaptaur sires for calf crops 1979, 1983–1984 and 1986–1988 on Belmont Research Station. Number of sires and progeny per group: Brahman, 24 sires with 159 progeny, Adaptaur maternal lineage 790546, five sires with 55 progeny, and remaining Adaptaur, 20 sires with 109 progeny.

Figure 2

Diagrammatic representation of the G × E × M for Bos taurus adapted to a temperate environment (e.g. Angus) and B. taurus adapted to a tropical environment (e.g. N'Dama) showing the proportional decline from optimal production potential for growth when there is no intervention by management to alleviate increasing levels of tropical environmental stress. The two shaded horizontal lines indicate the level of management required to maintain production potential.