Global dairy production at risk from extreme heatwaves, say researchers

Dairy production will be threatened by the increasing frequency and intensity of heatwaves, a study has found.

- Elsie McDowell

Drawing on records from more than 130,000 cows over a period of 12 years, the researchers report that extreme heat reduces dairy cows' ability to produce milk by 10%.

Just one hour of wet-bulb temperature – a measure that combines air temperature and humidity – above 26C can reduce a cow's daily milk production by 0.5%. Exposure to high temperatures also has a prolonged effect, with milk production still lower than typical levels up to 10 days after.

Using temperature projections for 2050, the report shows that by mid-century, average daily milk production could be reduced by 4% as a result of worsening heat stress.