Nanango, Queensland, district dairyfarmers Ian and Cathy Scott will be looking for bulls to use over their dairy herd that are above average for the new Heat Tolerance Australian Breeding Value (ABV).
Mr Scott said that in the past they had always picked bulls on type, production and udders.
Now they will be including the new Heat Tolerance ABV as well.
“We can fly to the moon but we can’t control the weather so we need to do everything possible to make things better for the cows, which includes breeding cows with good heat tolerance,” Mr Scott said
The Scotts recently received the Heat Tolerance ABV data for their herd and found most of their cows are above the Australian average, with ABVs of 100 or higher.
The Scotts milk 220 A2 cows year round and the herd includes 95 Holstein registered cows.
The herd history goes back more than 70 years under Scott family ownership.
Of the 95 registered cows in the herd, 90 had a Heat Tolerance ABV of 100 or higher. One cow had a Heat Tolerance ABV of 116. Those below 100 were only just below, with Heat Tolerance ABVs of 98 or 99.
“I was surprised our herd had such high ABVs for Heat Tolerance, but it was very reassuring given we can have very hot weather,” Mr Scott said.
“Now that we know that our herd has high Heat Tolerance ABVs we will be making sure we use bulls that keep those ABVs high.
“Our herd can handle hot conditions as long as it cools down at night time, but we can have challenges when we experience hot spells where temperatures don’t drop significantly at night."
Daytime temperatures on the Nanango farm can regularly climb above 30 degrees Celsius and are often coupled with high humidity.
There can also be periods where nighttime temperatures can stay in the mid-20s and there is no breeze.
The Scotts use a number of management strategies to help their herd deal with hot conditions.
“There is a sprinkler system over our feedpad, which we can use in hot weather, and we also have sprinklers at the dairy to help keep the cows cool,” Mr Scott said.
The new Heat Tolerance ABV has been included for the first time in DataGene’s December release of Australian Breeding Values.
Dairyfarmers wanting to breed for improved heat tolerance, look for bulls that combine a high Balanced Performance Index (BPI) with a Heat Tolerance ABV of greater than 100.