The Use of Transgenic Animal Techniques for Livestock Improvement

Abstract

Breeding of livestock has always been characterized by selection of spontaneously occurring mutations which could be observed in the phenotype of the animals. This could be achieved even though the genetic and molecular mechanisms underlying those phenotypes were not understood. Depending on the generation intervals of the species involved, years to centuries were required to establish certain breeds in livestock fulfilling the needs of man. Still the ideal farm animals have not been found. As higher meat, egg or milk yields are obtained, higher susceptibilities towards environmental influences such as climate or food changes or stress are observed and disease resistance declines, especially when animals are kept in large numbers under industrial production conditions. Since the first successful gene transfer experiments into the germ line of mammals, namely mice, were reported in 1980 and 1981, many attempts have been made to use gene transfer techniques in livestock in order to improve the overall quality and productivity of farm animals.