ABSTRACT
By the beginning of the 21st century, the unintended consequences of the drive to higher livestock productivity had become a matter of public and professional concern, debate and sometimes outrage. During the previous several decades the most important trend in food animal breeding had been genetic selection for a greater yield from one particular body part or function at the expense of the rest of the animal's anatomy and physiology, to the extent that some animal scientists predicted that ‘the end point of such selection will be disaster’. 1 The results are sometimes expressed in genetic terms – unfavourable genetic associations between production and health traits – or in terms of genetic selection that has unbalanced or overworked the animal's body. In any event, the result has often made animals less viable and less healthy and reduced the quality of their lives. At the beginning of the 21st century efforts are being made to reverse the damage and this story is far from over. We cannot as yet be sure what the future outcome will be from the point of view of the quality of life experienced by farmed animals.
