The chances of breeding sheep with a low risk of breech flystrike could be 11 to 20 years off, according to new research findings from an Australian Wool Innovation-funded project.
A study into the 'Rate of genetic gain in reducing breech flystrike' carried out by University of Adelaide associate professor Dr Forbes Brien and Dr Sam Walkom of the Animal Genetics and Breeding Unit at Armidale predicted how long it would take to breed resistant sheep without mulesing or chemicals.
The researchers utilised information from AWI's flystrike prevention program undertaken in a superfine wool summer rainfall and medium wool Mediterranean environment using average strikes, rather than high rates.
This was combined with modified MerinoSelect indexes.
Speaking at the MerinoLink Annual Conference in Armidale, AWI Sheep Health and Welfare program manager Bridget Peachey said updated calculations found there was some impact to other traits in selecting for breech flystrike resistance.
"We found that it may take between 11 to 20 years to reduce the incident of flystrike to less than one strike per 100 ewes per year," she said.
"This number is dependent heavily on the starting sheep type including initial level of wrinkle, breech cover, the environment and amount of emphasis being given on the trait relevant to others being selected for.
"We did find it would reduce rate of genetic gain for fleece weight by 30 per cent but this rate would still be positive and yet it had no impact on fibre diametre or reproductive rate."
Further research was conducted at CSIRO near Armidale to investigate if genomic selection could be used to breed breech flystrike resistance.
But no genes were found that had major impacts to breech flystrike or indirect traits, making it unlikely to predict using marker testing.
"However, associations were found through the sheep genome suggesting genomic predictions of flystrike resistance might be a possible approach," Ms Peachey said.
"In saying that though, the genomic breeding values for breach flystrike resistance were estimated with an accuracy of only about 33 per cent.
"This accuracy would need to be improved. Adding another 6000 animals to the database is expected to improve accuracy by 50 per cent."
Sending blowfly blind
Using the genome editing technology, CRISPR, researchers have been able to 'knock out' two genes within the blowfly to impact their vision and smell.
In 2015, research work was able to identify more than 2000 genes unique to the blowfly. But a new project finalised last year reduced those figures to 572 genes.
The more specific number allowed researchers to find 26 special interest genes thought to be involved in targeting sheep.
Using genetic modification, researchers have now been able to impair the development of the blowfly.
"We have managed to knock out the Y gene resulting in a blind dazzled fly and also the ORco gene which means the fly can't smell," Ms Peachey said.
"Whilst not affecting fly development, both these genes easily allow us to check if the technology is working."