That decision, taken at a meeting of the Australian Jersey Breeders Society last week, follows the news that genome testing showed Gratitude’s make up included 16 per cent of non-Jersey genetics.

The Australian decision will have major implications for breeders who have sourced semen from premium US bulls Gannon, Dale and Grieves and embryos from Gratitude families.

These were poised to have a significant influence in Australian herds but will no longer be recognised in the Australian herd book

Any daughters from these bulls born before the end of December 2010 will be eligible for the Stage 2 Genetic Register (GR2), with those born after that date relegated to the lower level GR3.

Bull calves from these sires will not be registered in Australia.

Jersey Australia said only a handful of these calves have been registered in Australia so far but industry reports confirm that the first sons from these bulls were poised to enter domestic AI programs this year and a number of breeders have also imported embryos with a view to potential exports.

One option that might be open to those breeders could be to register their animals in the US with semen exports from bulls standing in Australia but proven in offshore markets.

Peter van Elzakker from BOS Trading which markets Gannon in Australia said he respected the difficulty decision made by Australian Jersey Society directors last week even through he had hoped they would follow the US lead on this issue.

Society president Trevor Saunders said while understanding the challenges and short term loss their decision would produce they had a responsibility to the Jersey breed to maintain genetic integrity.