An East Gippsland farm case study on Staph aureus has found a highly accurate laboratory test that has been able to identify incognito cows infected with mastitis-causing bacteria.
Farmers Andrew and Lynaire Goold, Denison, Vic, were facing the prospect of losing significant portions of income for the rest of their lactation without an aggressive management approach.
"We were having prolonged, hard-to-solve somatic cell count (SCC) issues in the herd, and after many months in getting a few people to solve the problem," Mr Goold said.
"One of our vets suggested the new test and it was worth a crack to give us a bit of help."
Veterinarians ran cultures on samples from the top 20 per cent of the Goolds' high SCC cows, who had the bacteria within a 280-cow herd.
Results showed the presence of Staph aureus in 50pc of the animals sampled.
Mr Goold said the timing of test was "pretty good".
"The manager on our farm did a great job of using information, and in between us and our manager we chose what to cull, chose what to dry off and chose what to treat," he said.
"Within a pretty quick turnaround of about a month we were able to go from having some pretty significant issues on a daily basis to bringing back in premium milk again.
"We were not culling cows at a bad time so we could make those pretty big decisions without it being too out of the ordinary."
Mr Goold, who also works as a dairy farm consultant in New Zealand said he had seen staph issues in the past taken years to resolve.
Apiam Animal Health ProDairy regional lead Rob Bonanno used the laboratory test, called StaphGold, after cows failed to respond to usual interventions to the bacteria.
He said there was a close alignment of cattle with a high Staph aureus culture-positive high cell count with those cattle identified by the new test.
"When the culture result matched up with the StaphGold result, I knew it read well," Dr Bonnaro said.
The test was validated to screen whole herds, rather than just high-SCC cows.
After running the test across the main herd, Dr Bonanno said he was surprised to see nearly a dozen more Staph aureus-positive cows in the low cell count group that would have also potentially infected cows in the clean herd.
"Without the StaphGold test, we wouldn't have adequately reduced the risk in the clean herd and we would have increased the risk of exposure for the negative cows in the contagious herd," Dr Bonanno said
He said it was "a systematic approach" which provided more rigour around the culling, mating and other decisions to do with breeding.
Koru Diagnostics business development manager Alison Digney said events like the October 2022 Victorian floods could rapidly spread Staph aureus in herds, which farmers initially thought had minimal underlying issues.
"You start to see cell counts rise exponentially and people are shocked by the level of infection on their farm," she said.
"They might think that they have a couple of cases of subclinical, but it turns out to be one-third or half their herd.
"It blows their mind, but it shows they may have had an underlying problem for a long time."
Staph aureus in cattle is transmitted through infected teats or glands and is a cause of chronic or recurring clinical mastitis in dairy cattle.
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