The success of the application of genetics and
breeding science to animal production is most
apparent in the dairy, poultry, beef, and swine
industries. Not only have these gains come in
increased yields of usable animal products, they
have also been noted, perhaps more significantly,
in greatly improved protein and energy conversion
efficiency. While there have no doubt been
contributions from improvements in management
strategies, reproductive physiology, and nutrition,
recent estimates suggest that at least 40% of the
overall animal production increases are the result
of genetic improvement (Figure 1)