World-first genetic index helps Aussie farmers breed heat tolerant cows

In 2017, Australia introduced the Heat Tolerance Australian Breeding Value (HT ABV), a pioneering genetic index developed by Dairy Australia and Agriculture Victoria. This tool assesses cattle's ability to withstand heat stress, assigning scores based on statistical analysis of milk production data relative to temperature and humidity.

Trevor Parrish, a fourth-generation dairy farmer in Kangaroo Valley, New South Wales, adopted the HT ABV early on. Despite the region's moderate climate, local topography often traps heat, creating challenging conditions for his 300-strong Holstein herd. By selecting sires with higher heat tolerance scores for artificial insemination, Parrish has observed improved resilience in his cattle during hotter periods. 

Research indicates that heat stress can reduce milk yield by up to 40%, as cows eat less and expend energy cooling themselves. The HT ABV enables farmers to make informed breeding decisions, fostering herds better equipped to handle heat without compromising productivity.

Australia's initiative has garnered international attention, with countries like the United States exploring similar genetic tools to enhance livestock resilience. As global temperatures rise, such innovations are becoming crucial for the sustainability of dairy farming worldwide.

By integrating genetic selection with traditional management practices, Australian farmers are proactively addressing climate challenges, ensuring the viability of their operations in an increasingly warm world.