DNA testing solves a hornless cattle mystery

Researchers at The University of Queensland have discovered a previously undetected causal variant of the polled or hornless gene in Australian cattle.

Associate Professor Elizabeth Ross said the finding explains why polled cattle have been mislabelled as horned in commercial diagnostic tests. 

“Cattle producers are increasingly using DNA tests to breed horns out of their cattle herds because polled animals are safer and allow for more welfare-friendly management,” Dr Ross said.

“But current commercial genetic tests only detect 2 of the 4 known polled mutations.

“That means animals carrying other variants can be misclassified.” 

The team at Queensland Alliance for Agriculture and Food Innovation used advanced long-read sequencing technology to detect the rare Mongolian polled variant. 

“We were surprised to find this variant in animals from a Queensland herd owned by Consolidated Pastoral Company (CPC),” Dr Ross said.

“This variant isn’t included in commercial tests, so it was effectively invisible.”

While the animals in the trial were polled, whole-genome sequencing found none of the commonly tested polled variants in the commercial tests. 

The team then developed a test to validate the finding across the breeding industry.

“This is an exciting discovery by the team at UQ that will help the Australian cattle industry have a more accurate genetic test for polled and horned cattle,” CPC CEO Troy Setter said. 

“The accurate detection of cattle with polled and horned genetics will help us improve animal welfare and performance.”

Dr Ross said they were now testing for different mutations.  

“What this means for producers is that when a polled animal tests as horned, the test isn’t necessarily wrong, it just may not be looking for the right mutation,” she said. 

“To fix this at a commercial level, we need DNA test providers to include all known polled variants in their testing panels to correctly support breeding decisions, animal welfare improvements and industry confidence.”

Collaboration and acknowledgements