NEW technology involving stem cell implants from British breed bulls into Brahman bull testicles could lead to a much greater uptake of breeds like Angus in the Top End.
The CSIRO’s breed engineering team for Food Futures has been toiling away for the past few years developing this technology which is expected to take artificial breeding to the next level and could significantly lift the value of northern Australia’s beef industry.
Theme leader for the team, Nigel Preston, based at Cleveland near Brisbane, said the introduction of British breed genetics into Brahman dominated herds could greatly increase the meat quality, and hence the value of the individual crossbred offspring, by as much as 30 per cent when compared to the purebred Brahmans.
With the large herd sizes in the Top End, artificial insemination has not been practical on a large scale, and with the need for bulls to handle ticks and the harsh environments, simply putting a pure Angus or Hereford bull out with the cows was not a workable solution.
Mr Preston said the Brahman was tick resistant and suited to the extremes of the north.
So what if the Brahman bulls could do the artificial inseminating for them?
He said the issue with the northern herd was the six million or so Brahman and Brahman-derived cows needing to be covered – but what better way to do it than with bulls?
“What if you had Brahman bulls with Aberdeen Angus semen in their testes?” Mr Preston said.
This research was kicked off using rams in December 2008, as sheep were smaller and easier to handle.
Once they had success with sheep, they then switched their focus to cattle, which Mr Preston said were trickier due to their size.
The young Brahman bulls (five to six months and less than 200 kilograms) had their own stem cells “knocked down” with irradiation using a similar dose to a CT scan, which did not affect their somatic cells.
They had a few days of recovery before an ultrasound-directed needle was used to introduce the donor spermatagonial stem cells (or teste cells) from the chosen donor bull such as an Angus.
These young Brahman bulls then matured as sperm surrogates which could be used to sire Angus-cross calves in areas where Angus bulls would struggle to survive.
Mr Preston said this would allow commercial breeders to expand the use of elite genetics and would also have benefits in regions such as sub-Saharan Africa to increase the rate of genetic improvement in species such as goats.
“It’s ideally suited to systems where traditional artificial insemination isn’t practical,” he said.
Project leader, Sigrid Lenhert, said the 30pc increase in value was based on the extra dollars a grain-finished crossbred Angus/Brahman carcase would bring at the abattoir, compared to a pure Brahman carcase.
She said this profit prediction relied on a vertically integrated production system, where the producer who bred the calf could also background and finish it appropriately and market it advantageously.
At this stage, it was also unlikely all the matings from a surrogate Brahman bull would be Angus-cross, as the bull would also provide some of its own sperm, produced alongside the donor’s.
Therefore, the Brahman bulls still had to be good quality.
“We would source the type of high-grade bull calves producers are already happy to use, and carry out the procedure before they have reached puberty,” Ms Lenhert said.
“The technology in the form we currently envisage it being applied, therefore, offers the opportunity to wean a percentage of crossbred calves from an otherwise pure Brahman production system.”
NSW stud cattle breeder, Greg Chappell, Dulverton Angus, Glen Innes, said such technology could accelerate the rate of genetic improvement in the northern Australian beef herd.
He said when combined with tools such as DNA markers, the superior bulls could be identified and their genetics used more widely.
Mr Chappell said this could also bring much faster gains than the introduction of estimated breeding values had, as the gains on Breedplan were normally diluted when they reached the commercial end of breeding.
And he saw it as a great tool to get the most profitable genetics into the commercial sector quickly – a great help for producers stuck in a price-taking position.
“If we’re going to make any real price gains, they’re going to have to come from improvements in performance against specification,” he said.
“This is everything from market specs to parasite resistance.”
He said by using the DNA marker technology, the sperm surrogate technology could be used to get the right genetics into the right environment.
Mr Chappell said this could be seen by some bull breeders as potentially reducing their market, but “at the end of the day we need diversity for different environments and markets”.
“We need to be making more progress – in my lifetime the gains we’ve made have been miniscule,” he said.
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