CANBERRA, Australia – Australian researchers who developed a DNA test that can identify a lamb’s parents have also discovered a strong pecking order among rams.
The technology was developed by the Commonwealth Scientific and Industrial Research Organization and involves matching a small blood sample from the lamb with the DNA of the parents.
CSIRO said the technology is like assigning each sheep a bar code – or “baa code,” as it has been nicknamed. The breeder can tell a lamb’s real parents by comparing the codes, even when the sire is unknown or the lamb has been adopted by a different ewe.
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The system – considered to be 99 percent accurate – has been licensed to the New Zealand company SignaGen Molecular Breeding Solutions, which said the test will make it easy to identify the bloodlines of sheep with desirable qualities.
“This’ll be the first commercial testing service that will be available, probably worldwide, of its kind,” said SignaGen business manager Tom Watson.
“It’s been available in cattle before, but this will be the first sheep test kit that’s out and running.”
The researchers who designed the test also discovered that a virile performer in one group of rams can become impotent in another.
The extent of ram dominance came to light in a CSIRO study that set up four three-ram groups, each ranked as high or low index based on selection indices, or high or low grade based on traditional visual classing techniques.
In the high index group, one ram sired 50 lambs – 60 percent of the drop – another 33 and the third only one.
In the high grade group, one ram sired 44 lambs, another 30 and the third just two. The low index rams sired 61, 33 and 11 lambs and the low grade rams 47, 28 and 12 lambs.
Researcher Robert Slatter said the team was amazed that the dominance effect could be so extreme.
“Even breeders who were aware of it said they’d expect a fair share of the breeding for each ram, but it’s not the case,” he said.
“Producers may have bought top grade rams on the basis of performance and virility only to find they haven’t done their job because of the dominance effect.
“There’s nothing Merino breeders can do about dominance. It’s totally biological. It’s part of the natural pecking order seen in any animal group.”
But the new DNA testing means producers can move genetically superior rams found to be low on the pecking order from one group to another – or into a single sire mating scheme.
CSIRO said the new test will lead to more rapid gains in wool quality, growth rate and other desirable traits.
“Demand for DNA parentage testing is growing rapidly as producers see the benefits and the cost come down,” said Rob Woolaston, acting deputy director for livestock industries at CSIRO.
