Improvement of the health status of livestock populations by reproductive-biotechnological technologies

Established reproductive-biotechnological technologies such as artificial insemination (AI) and embryo transfer (ET) employing in vivo produced embryos are already valuable tools for the maintenance and improvement of the health status of livestock populations. Transmission of pathogens can be avoided by employing strict hygienic protocols. The intact zona pellucida acts as a very efficient barrier against pathogenic infections in in vivo derived embryos. New hygienic challenges arise with the growing use of in vitro produced, cloned and/or transgenic embryos. But the extended experience gained from the global use of in vivo produced embryos forms a solid platform for eventual commercial applications of these types of embryos. However, as the zona pellucida is structurally different or not intact in these embryos major research is needed to ensure that no disease transmission occurs. Further options for the improvement of the health status of livestock populations will evolve from transgenic technologies, in particular when the genome of the major farm animals has been completely sequenced and mapped. Today there are already promising examples for the potential usefulness of this approach to generate disease resistant populations. In the future, gene therapy, DNA vaccination and small interfering RNAs (siRNAs) will also play an important role to maintain and improve the health of farm animals. It is predicted that within the next 15-20 years a broad arsenal of technologies based on reproductive biological and molecular genetic tools will become available for improving animal health.