Traditionally, breeding programmes for farm animals have
focused on genetic ‘improvement’ of economically
important production traits. Consequently, productivity in
farm animals rose dramatically during the second half of the
twentieth century and effective selective breeding
programmes were a major factor. The milk yield per cow in
dairy and growth rate and feed conversion efficiency of
broiler chickens illustrate these changes vividly. However,
the combination of selective breeding narrowly focused on
production traits and the intensification of animal production
system have had consequences for the animals which
have become more at risk of behavioural, physiological, and
immunological disorders, ie poor welfare