Genetic trend for milk yield from doe evaluations in the northeast United States

Abstract

Milk production records of 306 Alpine, 72 LaMancha, 170 Nubian, 84 Saanen, and 235 Toggenburg does born in the Northeast from 1972 through 1979 were used to estimate trends of additive genetic value. Estimated transmitting abilities were doubled and averaged for all does born in each year to obtain yearly estimates of genetic value. Genetic trends from regression of yearly mean genetic value on year of birth for Alpine, LaMancha, Nubian, Saanen, and Toggenburg averaged 11.4, -7.9, 1.9, 14.6, and 11.7 kg per year. Genetic trends were less than theoretically possible, indicating that more effective selection schemes are needed, although because of the limited number of does, the trends may not represent actual trends.