Abstract
Efficient and welfare-friendly livestock production requires the control of nematode infection. Treatment with anthelmintics is the most widely used option, but this is threatened by the evolution of drug resistance in parasite populations. The exploitation of genetic resistance is an attractive method for nematode control. There are three strategies for utilizing genetic resistance: use of resistant breeds, cross-breeding and selective breeding. Resistant breeds of cattle and sheep have been identified but more research is needed, especially on cross-breeding. Selective breeding is most advanced in Australian and New Zealand sheep and remarkable results have been achieved. There is no doubt that selective breeding is an attractive option for nematode control. Genetic resistance should be utilized without further delay. Future developments may help to simplify and accelerate the adoption of genetic methods. Three areas that are likely to see further developments are: determining the distribution and nature of susceptibility to nematode infection and disease; better identification of resistant animals; and understanding constraints on the development of protective immunity.