Although the seasons run opposite down under, Australian dairy farmers are no strangers to heat stress. And although traditional heat abatement measures can help, researchers worldwide have been working on genetic advances for more built-in solutions, as well as ways for farmers to analyze and apply the data to their own herds. The Australian Broadcasting Corporation (ABC) recently reported on Trevor Parrish, a fourth-generation farmer who has been breeding his herd for heat tolerance using a 2017 tool, the Heat Tolerance Australian Breeding Value (ABV). Parrish, one of the first farmers to use the index, which sorts and rates animals by their ability to tolerate heat conditions, has seen “surprising” results, he told the ABC. Around a fifth of his herd ranked high on the index as more tolerant of heat and humidity, a statistic which can help inform his breeding decisions and, potentially, his bottom line.
Thuy Nguyen created the Heat Tolerance ABV during her agricultural bio-science research in the mid-2010s. The index uses genomics to look for genetic markets for heat tolerance; the cow is then ranked for both heat tolerance and the reduction in productivity that can accompany it. Both are expressed as a percentage, with a base of 100. For example, an animal with a Heat Tolerance ABV of 105 is 5% more tolerant to hot, humid conditions than average. Its drop in production will be 5% less than average. An animal with a Heat Tolerance ABV of 95 is 5% less tolerant to hot, humid conditions than average. Its drop in production will be 5% more than average. The ABC reported that the index could be a game changer for the industry and animal welfare around the globe. Stephanie Bullen, who leads the health and welfare arm of Dairy Australia, said, “I think it’s important to put the cow at the center of this conversation.” She also pointed out that the Heat Tolerance ABV index, which is the first of its kind, has generated interest across the world.
Nguyen, the tool’s designer, added that it has already been used in the U.S., and it has been found to translate well to conditions here.
