Gene Environment interplay                                       

Animals are selected within certain environments and normally the best performers picked for reproduction. But- the best animal in one environment is not necessarily the best in another. Take for example this high performing Aberdeen Angus bull, selected for a Scottish environment:

Long haired, highly performing in the cold - but what would happen with this animal in the tropics? Hence the use of EBVs estimated in animals selected in other climates is very problematic.

Genetics must be seen in context with the environment. Animals must be selected in the same environment in which their offspring later produce. EBVs based on genetic information obtained from concentrate fed bulls are nearly worthless if the production system is pasture based!