By concentrating on the mechanics of increasing the rate of change, researchers have been able to avoid the perplexing question of the value of change. Maximizing the rate of genetic change can indeed be valuable, but only to the extent that selection objectives are valid. Stated another way, rapid change will be good if we are reasonably assured that such change will lead to significantly increased production efficiency. In dairy cattle, increased milk production per cow has unquestion ably increased overall efficiency. The dairy industry has been blessed with a single trait so important that breeders and researchers have been justified in going all out to genetically change dairy cattle in this character.
Beef cattle are different, however.
Show rings, gain tests and sale averages have served to reassure breeders that continued selection in a particular direction was correct, but hard evidence is lacking. Today, in the mid 1980's, seedstock producers are becoming more appreciative of this fact. We know that intermediate levels of performance for traits like milk production, birth weight and mature size are optimal, that efficiency results from a delicate balance of many traits interacting with environmental factors, and that overall genetic merit is complex in nature and difficult to quantify. We know that different animals are appropriate in different situations and that, in some cases, efficiency is limited by environment not genetics. These realizations have complicated the jobs of seedstock producers and researchers immensely.