Genetica

Staying good while playing God – Looking after animal welfare when applying biotechnology
Peter Sandøe, Stine B. Christiansen and Christian Gamborg University of Copenhagen

Animal breeding was, until the beginning of the twentieth century, a relatively uncontrolled activity based mainly on the animal’s physical appearance. The early animal breeders did not really have the knowledge and toolsto predict and control what they were doing. This changed in the first half of the twentieth century, when Mendelian genetics was applied in farm animal breeding. Later, the second half of the twentieth century saw the development of new forms of animal biotechnology such as the freezing of semen, embryo transfer, in vitro fertilization, gene transfer and cloning – all of which allow scientistsand breeders even greater control over future animals.

With greater control comes greater responsibility and, in modern democratic societies at any rate, a higher degree of accountability. Certainly the new technologies prompt a range of ethical questions concerning animal welfare, biodiversity and human interference with nature. In this paper focus will be on the effects of breeding and otherforms of biotechnology on animal welfare. In the first section it will be described how modern breeding and biotechnology has developed. In the second section consequences for animal welfare will be presented and discussed. Finally in the last section there will be a brief discussion of some of the ethical issues raised.

New ways of changing animals
The main breakthrough in the development ofmore advanced breeding practices came at the beginning of the twentieth century with the re-discovery of Mendelian genetics. With this new basis for understanding the heritability of different traits it became possible to design future generations of domestic animals using measurements of the genetic potential of possible breeding animals. From the beginning and for a long time this approach wasmainly used in the breeding of farm animals. The genetic potential of animals came to be measured by looking at the performance of their ancestors, siblings and offspring rather than looking merely at the performance of parent animals. Furthermore, advanced biometric models were put to use to estimate the genetic potential of possible parent animals. Breeding animals were now selected

byreferring to breeding goals – that is, goals that define the relative weight of the various traits that the breeders are trying to enhance. The fact that it is possible, generation after generation, to achieve progress on a breeding goal is based on the biological insight that relevant genetic properties vary among offspring. By always breeding on from the best-performing animals it is possible, over anumber of generations, gradually to improve average performance.

For many years the main focus in the breeding of farm animals has been on production traits. Examples of such traits include milk yield in dairy cows, the number of eggs laid by laying hens, and growth and feed conversion in meat animals. The results have been staggering. For example, between the early 1960s and the late 1990s thetime needed to produce a slaughter-weight broiler fell from 80 to 40 days, and the required feed consumption halved (Havenstein et al. 2003). Over the same period, milk yield in most dairy cow breeds have more than doubled (Christensen 1998). Admittedly, these achievements derive in part from improved management practices. However, to a large, and still increasing, extent they are the outcome ofgenetic changes brought about by systematic farm animal breeding.

More recently, modern biotechnologies have also been used by breeders in their work with some farm animals. The technologies in question belong to what is called reproductive biotechnology, which aims to control (and often accelerate) the process of breeding. The first technology of this kind to be developed was artificial...