Veterinary research
When clinical cases, such as the puppy with a deformed front limb, are extrapolated to the clinical research environment it is clear that the development of diagnostic and therapeutic tools leads automatically to their application, unless the cost of their application is truly excessive. For this reason, the possible implications of research projects should be analysed and discussed at regular intervals, particularly during the initial stages of planning. During discussions, however, care should be taken to avoid extrapolating information pertinant to man to animals and vice versa. A few examples in which this danger is relevant are given below.

1. Infectious diseases
Major efforts have been, and continue to be, made in order to develop vaccines against infectious diseases that affect man. When patients do become infected they usually receive good medical care and, if necessary, are treated in isolated units. However, for animals the situation is quite different; there is a much wider range of treatment strategies to consider. The most drastic course of action is the destruction of all diseased animals as well as those that are clinically healthy but have had contact with possible sources of the disease. To select the optimum strategy for animals affected by disease, man must consider the differential moral status he assigns to domestic animal species; for instance, diseases affecting production animals may be eliminated by the large scale destruction of animals. Complex legislation and international treaties have been designed for the organised control of animal diseases by such means. In contrast, equally serious diseases in companion animals are more likely to lead to the development of vaccines.

2. Cloning and stem cell technology
The recent development of nuclear transfer technology has enabled the production of many genetically identical offspring from a single adult animal [3]. Briefly, the technique involves the transfer of nuclei from donor cells into enucleated fertilised ova, which are deposited into the uterus of unrelated recipient females; novel but genetically identical individuals are born. The scientific potential of this technique is immense. It enables the development not only of fundamental research into the function of genes, but also of basic research into phenomena such as ageing. Not too surprisingly, it has raised many moral objections, the most prominent being its potential application for the production of human clones. Pressure groups that oppose the use of the technique in animals foresee major trouble if the technology were ever to be applied to man. Some people predict that powerful individuals might attempt to produce the equivalent of the "Boys from Brazil" (clones derived from Adolf Hitler), or that extremely wealthy people may wish to clone themselves in order to guarantee a supply of fully compatible tissues and organs for transplantation, in case they should need them later in life. The only way to make such scenario's unlikely is the enforcement of moral and legislative restrictions rather than there being a limitation on available technology.

Interestingly, the development and use of a very similar technique, namely stem cell technology, has been given a novel impulse recently and is related to the much debated and contraversial topic of xenotransplantation (organ transplantation between species). The development of xenotransplantation arose because the demand for donated human organs and tissues for transplantation far outweighs their availability, there is a practical bottleneck to the development of transplantation therapy. It is well known that pigs are the most likely candidate animals to serve as donors of organs and tissues for human patients, but animal welfare organisations have objected to this novel 'instrumental' use of them that bears no relation to meat production. They claim that the animals' welfare would be adversely affected by keeping them under the required Specific Pathogen Free (SPF) conditions. However, this argument is not really valid because pigs can be kept very comfortably under these conditions, so long as cost is not an issue. There are also technological and biosafety problems that must be solved prior to the experimental clinical application of organs in human patients. In addition to overcoming the immunological barriers that exist between species and lead to the rejection of transplanted organs, there are other aspects of xenotransplantation that require extensive research [4]. The first is the proper functioning of an organ after transplantation, including its physiological compatibility and longevity, and the second is the putative risk of activating retroviruses from their dormant state in the genome of the donor animal. The latter is estimated to be the most complex problem because of its possible epidemiological significance.

Many of the biological problems presented by xenotransplantation, ignoring for a moment the ethical dilemmas, could be overcome by instead using the more sophisticated stem cell technology. The potential uses of this technology are immense and have been quickly recognised by the biomedical industry. For instance, the corporate policy of one British biotechnology company, already involved in xenotranspantation developments, switched immediately to human stem cell technology after the country changed its legislation on the use of human embryonic material in research to enable more extensive experimentation. Briefly, the technology involves the removal of nuclei from a patient's cells and their transfer to enucleated fertilised ova. The cells are then cultured under very specific conditions that lead to their differentiation into the type needed to treat the failing organ. The technology is dependent on nuclear transfer and generates omnipotent embryonic cells, which means it is essentially the same as the method for cloning humans. Thus, the prudence gained over the cloning of animals appears to have evaporated rapidly. In addition, the human embryonic material required to further develop stem cell technology can only come from human embryos, which introduces numerous ethical dilemma's concerning research with material that has or had the potential to develop into a unique human, even though the intention now is to restrict the use of embryos to only those 'left-over' after women have received infertility treatment.

In conclusion then, the cloning of animals has been, and continues to be, a much debated topic because of its potential application and misuse in man. However, the development of this and related technologies, like stem cell technology, also has the potential to be enormously beneficial to man. As a result, key aspects in the ethical debate on the cloning of animals are now being considered with considerable urgency.

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