Heat Stress Management in New Zealand's Dairy Industry Gains Momentum
New Zealand's dairy industry is increasingly focused on finding solutions to mitigate the effects of heat stress on cows, a condition that impacts milk production and animal welfare. The issue is becoming more urgent as climate change leads to warmer, drier summers, posing a significant risk to dairy regions across the country.
DairyNZ, in collaboration with AgResearch and Fonterra, has developed the Grazing Heat Load Index (GHLI) to better predict when and how heat stress affects cows in outdoor grazing systems. This index considers factors such as temperature, solar radiation, and wind speed, offering a more tailored approach than traditional temperature-humidity indices used in indoor housing systems.
Research efforts are supported by the New Zealand Bioeconomy in a Digital Age (NZBIDA) programme and involve the use of digital tools like wearable sensors and milk vat monitoring systems. These technologies provide real-time data on cow temperature, activity, and production, allowing researchers to gain precise insights into the impact of heat stress.
Over the past year, DairyNZ has conducted surveys and workshops with farmers to gather their input on heat stress risks and mitigation strategies. Farmers have expressed interest in understanding the cost-effectiveness of various solutions and the specific conditions under which heat stress most significantly affects milk yield.
Currently, about 65% of surveyed farmers in the Waikato/Bay of Plenty region and 40% in Canterbury have installed misting or sprinkler systems to help combat heat stress. DairyNZ plans to conduct farmlet trials to test and compare these and other mitigation strategies, such as adjusting milking frequency or timing to avoid peak heat periods.
The outcomes of this research aim to provide farmers with practical, cost-effective strategies for managing heat stress, ultimately improving cow welfare and farm performance. This initiative is part of DairyNZ's Enhanced Animal Care Programme, funded by New Zealand dairy farmers through the DairyNZ levy.
