Abstract

The possible impact of developments in artificial insemination (AI), multiple ovulation and embryo transfer (MOET), sexed semen and embryos, cloning, physiological markers, genetic markers and transgenic livestock on rates of genetic change are reviewed and discussed. Previous theoretical predictions have exaggerated the potential increases in rates of genetic change available from MOET, particularly in small, closed MOET nucleus schemes. Sexing of semen and/or embryos has a relatively small effect on rates of genetic change, but sex control can potentially have a dramatic effect on the efficiency of farming systems. Developing techniques to produce large clone families in livestock will increase rates of genetic change, particularly through faster dissemination of superior genotypes to commercial populations. A cost-benefit analysis of some different strategies for increasing genetic change in the New Zealand dairy cattle population has identified that useful contributions could come from AI (by doubling current bull coverage) and from MOET and genetic and/or physiological markers. Equally important economic returns were identified from increasing the number of bull mothers continuously bred by AI. The impact of transgenic animals, gene mapping and genetic markers (linkage) on rates of genetic change is likely to take much longer (10- 20 years) than the reproductive techniques.

JF, Smith, GJ Cruickshank, E Payne, J Konlechner, J Parr, LT McGowan, and RR McLaughlin

Proceedings of the New Zealand Society of Animal Production, Volume 50, , 145-148, 1990