Heat stress is a growing challenge on dairy farms across the country.
The physiology and behaviour of cows change when they experience heat stress, and some cows cope better than others. It is also expected that heat stress may increase in future as daily temperatures continue to rise and extreme hot weather events become more frequent.
The ability to predict heat stress in dairy cows could help inform on-farm management decisions, such as timing of milking, choice of paddock, changing milking frequency, breeding choices, tree planting, and installing portable shade structures.
Until now, there have been various ways to assess heat stress, including animal measures and weather conditions, with the Temperature-Humidity Index (THI) being a common method for measuring cattle heat load. However, it doesn't include factors like wind or sunlight, which could be major factors in how hot it feels to them.
DairyNZ has invested in heat-stress research with animal scientist Dr Charlotte Reed and senior animal care specialist Jac McGowan to provide evidence for solutions that improve cow comfort, protect performance, and support sustainable, future-ready farm systems.
These scientists are now in the final stages of an on-farm trial at DairyNZ’s Scott Farm in the Waikato to test common mitigation measures and assess their return on investment.
At the farm, five mobs of cows have been fitted with rumen-temperature boluses, pedometers, and wearable technology to provide real-time data for testing the impact of various mitigation measures.
Read more in the latest issue here
