Rural News: Cool Cows
Breeding cows with increased tolerance for high temperatures is looking to yield positive results at Agriculture Victoria in Australia
Researchers at Agriculture Victoria in Australia are now one step closer to unlocking the genetic code to breeding dairy cows with greater tolerances for high temperatures.
Agriculture Victoria research director Ben Cocks said researchers have identified five new genes strongly associated with heat tolerance in dairy cows.
The findings come after studying almost 500,000 milk records from approximately 30,000 Holstein cows, which is far larger than previous datasets used.
"This large increase in sample size has helped the team pinpoint the specific regions in the cow’s DNA that controls heat regulation, helping us better identify which cows are more heat tolerant than others," Ben says.
When temperatures and humidity rise, dairy cows reduce their feed intake, resulting in a decrease in milk production. In areas such as Northern Victoria, this means more than 100 days a year are considered too hot for dairy cows to produce optimal amounts of milk.
"By breeding cattle that can adapt to rising temperatures, we’re helping create a more resilient dairy industry under a changing climate," Ben says.
"This gives farmers the support they need to minimise the impact of heat on their herds and maintain milk production."
Researchers also discovered that genes associated with the nervous system were critical for heat tolerance.
The research team at Agriculture Victoria are using the results from this study to begin a five-year research project — testing and comparing the newly found heat-tolerant genes with DNA from dairy cows across Australia to find new ways to identify the most heat-tolerant cows for farmers to breed.
This world-leading study is part of the DairyBio programme –a $55 million research partnership between Agriculture Victoria, Dairy Australia and the Gardiner Foundation.
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