Relationships between adaptive and productive traits in cattle, goats and sheep in tropical environments

This paper reviews the literature to determine the extent of genetic variation for resistance to stressors of tropical environments in beef and dairy cattle and goats and sheep. It also investigates the existence of genetic antagonisms that would preclude simultaneous improvement of productive and adaptive traits. Most adaptive traits are at least moderately heritable, meaning breeding to improve adaptation is feasible. It also appears that in cattle, goats and sheep which are well-adapted to the tropics, there are very few antagonistic correlations that would preclude simultaneous genetic improvement of both productive and adaptive traits to maximise herd profitability. The major constraint to genetic improvement of adaptation in tropical environments is the ability to accurately and cost-effectively record the fixed effects and phenotypes required for selection programs. Options to overcome this constraint are examined.