Genomics aid herd decisions

Speaking at the DairySA Innovation Day at Mount Gambier, she said calves were the future of the business and genomics could provide an idea of what that future might look like.

Ms Webb-Wilson said of the things that can affect a cow’s performance – seasonal conditions, location and feed – many can be difficult to manage. 

“Genetics is easy to control,” she said. “Using a different straw or bull, it’s a small change but it has a big impact on the business.

“These decisions and permanent and compounding and it can be expensive and time-consuming to fix a bad decision.”

Ms Webb-Wilson said data from the ImProving Herds through Dairy Australia showed the top 25 per cent of cows, based on the Balanced Performance Index, were worth an extra $300 each, compared to the bottom 25pc.

“Genomics can speed that (improvement) up,” she said.

Since 2012, the industry has been collecting 41,366 genotypes, to assess breeding values based on a DNA sample.

Ms Webb-Wilson said the reliability of genomics to assess the breeding value for a new-born heifer was 76 per cent, while for fertility, it was between 50-60pc.

After seven years of milking, the reliability for the protein breeding value is 78pc.

“At year zero, you can make estimations that would otherwise take eight years,” she said.

Ms Webb-Wilson said dairyfarmers often ask about the likelihood of culling a heifer that might have developed into one of the top 25pc cows.

“Across the project, the chance of a calf predicted to be in the bottom 25pc to end up in the top 25pc was 2pc,” she said.

“Animals move within groups but are not jumping from top to bottom or bottom to top.”

Ms Webb-Wilson said this data can be used in culling decisions, but also in breeding choices.

“A farmer might join the bottom 25pc of the herd to beef bulls and use sexed semen for the top 25pc,” she said.