PREVENTION, through the use of the DNA testing and breeding away from lines with known genetic defects, is crucial in preventing calf losses.
The message was spread today at the Angus Australia annual general conference in Armidale, NSW.
The University of Illinois' Prof Jon Beever, the man responsible for developing DNA tests for the deadly recessive genetic disorders, AM, NH and CA in Angus cattle, said Angus breeders had a responsibility to prevent the further spread and rise of genetic disorders.
"At today's (bull) sales, we see extremely few animals marketed as carriers in the US," Prof Beever said.
This is in stark contrast to Australia where bulls tested and proven as carriers have been sold by many noted studs this year, often for averages prices as high as the rest of the catalogue.
When two carriers of a recessive genetic disorder a mated, 25 per cent of the calves will be unaffected, 50 per cent will be carriers and 25 per cent will be affected - in most cases severely deformed, or dead.
Genetic defects with a recessive pattern of inheritance are manageable if present in the population at a low allele frequency, Prof Beever said.
But recognition of the of the defect is often too late, when it's sufficiently high enough to cause losses, and that's why it can appear some 20 years after the origin of the gene.
"AM has been in cattle since 1975, NH since March 1990 and CA since the 1970s," Prof Beever said.
And the threat of these genetic disorders is directly proportional to the population size of carriers, he said.
"When Precision 1680 was born in 1990, he was the only animal in half a million Angus cattle in northern America with that genetic defect (NH). Now 10 per cent of the animals within the breed have the potential of having it.
"Genes controlling defects and selected traits are linked, he said, meaning that even if line breeding is avoided, producers chasing traits associated with a certain bloodline can still be at risk.
"You need to think twice about that dead calf and, instead of saying, well I only expected 95 or 97 per cent (live) calves, ask why it happened.
"We have the tools to breed around them (genetic defects), but we don't want to get too lax about it . . . this could be a major problem in 15 years time."
Prof Beever said producers needed to approach testing for genetic defects like vaccination.
"There are lots of opportunities to be proactive and address these problems," he said.
And now, with cattle returning 20 to 30 per cent more this year compared to last in both the US and Australia, is the time to think more carefully about managing genetics for a reduction in calf losses and greater profits, he said.
