What of animal cloning?

It is agayns the proces of nature

Geoffrey Chaucer 1343–1400

The veterinary profession has been slow to express its views on the pros and cons of animal cloning.

Those in favor of animal cloning are quick to point to the potential advantages. Cattle, sheep, goats, and pigs have been cloned; so from a producer's standpoint, theoretically, numerous offspring of known sex could be obtained from a few superior producing or disease resistant animals to develop high quality herds or flocks. Transgenic animals that have been developed for the production of human therapeutic proteins and other proteins, such as spider web, or as sources of cells, tissues, or organs for xenotransplantation, could be produced faster and less expensively, and more efficiently, than by the methods that were used to create them in the first place; fewer embryos required, all offspring transgenic and of known sex. Cloned animals could also be a valuable resource for biomedical research and in the rescue of endangered species.

There is, however, a downside to animal cloning, which is of importance to those concerned with animal welfare and which remained in the shadow of the “upside” until the question arose as to whether cloning of humans should be allowed. In a recent review of cloning by somatic cell nuclear transfer, Wilmut et al (1) have described the problems that have been encountered to date, mainly in cattle and sheep. In various laboratories, only 0% to 4% of adult or fetal somatic cell constructs have developed to become live fetuses; in addition, there is a high rate of fetal, perinatal, and neonatal loss. Many cloned offspring die within 24 h of birth, associated with, for example, respiratory distress; increased birth weight; or cardiovascular anomalies, some of which have resulted in hypertrophic liver and dilated major blood vessels. Abnormalities associated with subsequent development include failure of the immune system, structural abnormalities of the brain, digestive dysfunction, enteritis, and umbilical infections. There is also the question of the true biological age of clones and the potential for premature aging.

Should scientists overcome the existing problems and cloning becomes commonplace and commercially viable as a reproductive tool for the livestock industry, it will have its effect on biological diversity, leading to undetermined problems.

Presumably animal cloning conducted at universities, at companies associated with universities, and at not-for-profit research institutions is under the aegis of an institutional animal care committee. But what of companies that are out to profit from cloning animals and are not under animal welfare guidance?

The issues regarding animal cloning raised here are far from complete, but hopefully they are sufficient to cause the veterinary profession to look into the pros and cons of animal cloning, so that it can speak for the welfare of the animals involved and give appropriate guidance to livestock producers and those owners of companion animals (dog, cat, horse) who are tempted to have their animal cloned by companies offering the service (2,3).