Meat & Animal Product Safety

In the last 40 years a number of modern techniques for improving animal lines have been developed. Artificial insemination has already had an enormous impact on the dairy industry. Techniques such as in vitro fertilization, embryo cloning, nuclear transplantation and transgenesis are reaching maturity. These techniques and their potential effects on the environment, genetic diversity, animal production and society have been discussed by George Seidel (1989; 1991). Introducing food products into the market place requires that the safety aspect be fully analyzed and documented so that healthy transgenic animals will be at least as safe as the traditional animals from which they were derived. The classical breeding of familiar food animals has been practiced since antiquity and has never resulted in a hereditary trait that made animals unsafe as food. Traditional breeding is accomplished by focusing on a desirable trait, such as milk production or fat content, and breeding only those animals which best exemplify the trait. If the trait is quantitative, this practice moves the population mean in the desired direction. The cause of the improvement is unknown. Theprogeny results from thousands of selections between paternal and maternal genes and the genes responsible for the improvement in the phenotype are rarely, if ever, identified. There is little knowledge of the physiological mechanism underlying the phenotypic change. Yet, this approach has been safe and successful and is exemplified by the dairy industry where selecting semen from bulls with high-producing daughters more than doubled the milk output per cow in the twenty years following 1955. The genetic events associated with traditional breeding are safe; consequently, only the unique features of transgenesis are examined here. One can organize the unique features of transgenesis into three categories: the genetic construct (i.e., the DNA introduced), changes resulting from the integration of the construct, and the nature of the gene product.