BY L. DALE VAN VLECK

TWO MEN, BOTH born in the farming community of Page County, Iowa, had more impact on modern animal production in the United States and the world than any other pair of scientists since the rediscovery of Mendel's laws. Both men specialized in the area of agricultural sciences known as animal breeding and genetics. The first, born near Shambaugh, Iowa, on January 3, 1896, was Jay Laurence Lush. The second, born near Coin, Iowa, on April 1, 1911, was Charles Roy Henderson, who became a graduate student under Lush at Iowa State College in 1946. Lush also preceded Henderson as a member of the National Academy of Sciences.

Lush, and later Henderson, led the profession for nearly all of the twentieth century. Lush outlined the basic principles and methods for genetic improvement. Henderson followed by developing methods first to estimate the genetic parameters needed for the application of those principles and then to predict most accurately the genetic values of animals available for selection. Henderson's methods have been since the 1950s—and will be for the foreseeable future—the basis for genetic evaluations for every breed of every class of livestock in every country of the world. Millions of beef cattle, dairy cattle, pigs, sheep, and other