Ethical considerations in the selective breeding of animals

Abstract

It has been known for some time in veterinary medicine that certain breeds of animals show predilections for particular diseases, and furthermore that particular diseases may be confined entirely to one breed or a small group of breeds. Most veterinary textbooks discuss breed predilections for disease as relates to their specific subject matter, and at least one textbook is devoted entirely to the subject of breedassociated disease.1 Breed-associated disease can arise in a few ways. First, morphological breed standards can directly cause disease, or can otherwise exacerbate disease. Second, because “purebreeding” is essentially inbreeding,* the creation and maintenance of particular breeds decreases genetic heterozygosity as compared to an outbred population, thus increasing the probability that a given individual will possess two copies of rare, recessive disease-causing alleles. Third, disease-causing alleles may be inherited though their genetic linkage to loci corresponding to traits that are being selected for.