In a world-first, Australian Breeding Values have introduced Heat Tolerance ABV to aid dairy farmers in breeding greater heat tolerance into their herd.
DataGene chief executive officer Matt Shaffer said although environment and management conditions had a big impact on a cow’s response to the heat, genetics also played a role.
‘‘Advances in genomics allowed the Dairy Bio team (a joint initiative between the Victorian Government and Dairy Australia) to identify gene markers for heat tolerance,’’ Dr Shaffer said.
‘‘The Heat Tolerance ABV allows farmers to identify animals with greater ability to tolerate hot weather with less impact on production.
‘‘If breeding for heat tolerance, look for the exceptional animals that are strong for both BPI (Balance Performance Index) and heat tolerance.’’
To breed for improved heat tolerance, DataGene recommends bulls with a high BPI and a Heat Tolerance ABV of greater than 100.
While a strong focus on heat-tolerant bulls may improve fertility, it may also compromise production.
Ross Gordon, who has 640 Holstein cows on his Cohuna property, said heat tolerance was a genetic marker he would be interested in using.
‘‘If two bulls have a comparable BPI, but one has a better Heat Tolerance ABV, then that’s the one we will be selecting,’’ he said.
‘‘We can’t control the weather but we can do our best to breed cows that have improved heat tolerance.’’