BEEF producers often select the biggest, heaviest heifers to retain within their herds but Thomas Elder Institute head Michael Wilkes expects more and more commercial herds will soon be using a simple DNA test to take the guesswork out of these decisions.
"Without any other information, we are always going to pick the biggest, shiniest heifer out the front of the mob and put maximum resources into her but just because she may have been born early in the calving season doesn't mean she is genetically the best," he said.
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Speaking at the Elders-PIRSA Best Practice Demonstration Farm Field Day at Struan, Dr Wilkes said genomics were becoming more accessible for commercial herds.
In the past, genomics was predominantly only available to stud breeders and had relied on a heavy amount of performance measurement but Dr Wilkes said the extensive information collected throughout the years was now able to be used in ranking animals in commercial herds for a range of maternal, performance and carcase traits.
TEI and Elders are working with genomics provider Neogen Australasia to show how their Igenity genomic test can help beef producers select the best animals on genetic merit alone, minimising environmental influences.
This is being demonstrated at the Struan Best Practice Demonstration Farm where tissue tests from 152 of Struan's Angus steers and heifers were taken at calf marking.
The Neogen Igenity® tests rank animals from 1-10 for 15 different traits - from milk, docility, to growth and feed efficiency and marbling - based on the presence of certain genes.
"When we get into a situation of needing to select the highest potential individuals to keep when times get tough or we want to put a lot of selection pressure on our herd, then we can make those decisions earlier," Dr Wilkes said.
These animals are being followed through mating and calving for the heifers and to slaughter for the steers to compare the genomic scores with the actual performance.
Yearling weight is the first trait that has been analysed in detail. The steers and heifers scores were spread from 3 to 8 for yearling weight.
Dr Wilkes says comparing the different scores with the weights of the animals at 12 months of age, they found the higher scoring animals were noticeably heavier.
"The 3 scores were considerably lower than the average," he said.
"There wasn't a tremendous difference in the 4,5 and 6 score animals in terms of average weight currently, but those higher scoring animals (7 and 8) averaged 20 to 40 kilograms higher.
"Basically for every single point score increase, there was about a 14.7kg increase in yearling weight so if we can shift that herd average from 5.9 to 6.9 over 150 animals over time, that starts to add up into a considerable amount of additional gain."
On these benefits, along with high cattle prices, Dr Wilkes said the cost for basic genomic testing of $42 was "relatively easy to write off".
Another big advantage of Neogen's tests was the reference herd the company used was International Genetics Solutions' database.
This represented millions of cattle from multiple breeds in North America, Australia and New Zealand and enabled the comparison of crossbred animals as well as purebred ones.
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Dr Wilkes believes it will be a big benefit for commercial breeders to know where their cow herds sit for certain traits when selecting bulls. It could also be really useful for commercial in-herd bull selection in situations where larger breeders may be looking to retain some of their bull calves.
"There are also some future opportunities that we are seeing coming out internationally about marketing cattle on the test results and even testing feeder steers and looking at their ability to perform for marbling and eye muscle, particularly in long-fed programs where we are chasing high value carcases,"he said.
