Genetic options to replace dehorning in beef cattle—a review

Abstract

Breeding polled cattle is a long-term solution to problems commonly associated with horned cattle. The current practice of dehorning does not eradicate the problem and is an animal-welfare concern. The present study reviews the current state of knowledge on the genetic basis of polled inheritance in cattle. The poll/horn condition is presumed to be under a relatively complex mode of inheritance whereby poll, scur, and African horn genes segregate independently, but interact with each other to produce polled, scurred, and horned animals. Molecular genetic studies have mapped the polled gene to a specific region on bovine chromosome 1 in Bos taurus animals, but the actual gene is still to be located. Scur and African horn genes have not been studied extensively at a molecular genetic level. With the current advances in molecular genetics and statistical methods, there is large scope to undertake new research programs to develop DNA tests that identify homozygous/heterozygous animals for poll, scur, and African horn genes. This would assist faster introgression of the polled condition into beef cattle populations. Existing scientific evidence to counter or support industry perceptions about the production-related issues of the polled condition are presented.