TWO young SA-based researchers are hoping to improve meat eating quality on-farm and further along the chain.
University of Adelaide School of Animal and Veterinary Sciences post doctoral candidates Rudi McEwin and Farrah Preston are excited about how their research could assist the beef industry.
Ms McEwin’s PhD, which she hopes to complete later this year, involves working with 3D Genetics’ Wagyu herd in NSW to develop a customised breeding program using genomics and breeding values for individual animals to make better mating decisions.
A key focus has been identifying high-marbling animals.
She says they are getting promising results using genomics but also utilising a high resolution camera at the abattoir to photograph and record marbling of individual carcases.
Ms McEwin says the existing Aus-Meat grading system for marbling – where an assessor subjectively gives a carcase a marble score in the chiller – is only moderately heritable at 0.3 to 0.5, but this can be significantly improved up to about 0.8 using genomics and a camera to enhance the accuracy of phenotype measurements.
Research shows that having denser genotyping gives better results and a better prediction of traits, but what is the ideal?
- RUDI McEWEN
"There is a similar pattern with the camera estimate for eye muscle area, although it is not as heritable as marbling,” she said.
Several beef genomic tests are available commercially analysing 30,000 to 50,000 single DNA base variations, but Ms McEwin's research is also interested in whether a test looking at fewer sites could remain effective but also be cheaper.
"Research shows that having denser genotyping gives better results and a better prediction of traits, but what is the ideal?” she said.
“Is there any benefit in sequencing the whole genome?”
“In less outbred populations such as Wagyu, we think there may not be a reason to go as far but it may be different for Angus and other breeds.”
She says they are getting good results testing as few as 1200 single nucleotide polymorphism sites, with the Wagyu animals being ranked in a similar order for key traits as they were in a more intensive test.
Ms McEwin believes genomics may replace the ultrasound of live animals to collect carcase information, but she says breeders will still need to visually assess animals, especially for good feet and legs.
"It doesn't matter how good an animal is, if it can’t walk it is no good," she said.
After completing her honours on dark-cutting beef in pasture finishing systems, Farrah Preston has turned her attention further down the supply chain, studying pre-slaughter factors for her PhD.
“There has been a lot of work around on-farm management but not as much on handling when they get there (to the abattoir) and its impact on eating quality,” she said.
All cattle must be washed at the abattoir prior to slaughter to meet Australian and international health standards, but Ms Preston says the practises vary greatly between different plants due to a lack of formal guidelines.
Ms Preston, who is midway through her PhD, is hoping to identify the optimal hide washing method to minimise stress and hence reduce dark cutting incidence.
She has recorded the washing method and carcase grading data of more than 3000 animals processed at Teys’ Naracoorte abattoir in the past three years.
“Hopefully I can find that one wash is equivalent to four washes and it is the technique rather than the number of times that matters, so while we are getting the cattle clean we are also meeting food safety standards, good animal welfare and meat quality,” she said.
Ms Preston says Teys Australia has been very supportive of her research, along with many producers.
“Even though they are already doing a good job, they are not standing still but always striving to better their industry practices," she said.
