Real-time data to help dairy farmers assess heat stress risk

Cargill UK and Lallemand Animal Nutrition are launching live temperature and humidity data online to help dairy farmers monitor the risk of heat stress in dairy cattle this summer.  

Cargill is installing automated, cloud-based data loggers on 30 dairy units across the UK.

Live readings will be relayed by wi-fi to a dedicated web page to show the temperature and humidity Index (THI) by region, alongside the actual temperature in sheds for the selected farms.

It will also give the average temperature and THI for the previous 24 hours and the previous week.

It will use this information alongside herd fertility and production data to identify the real-time impact of temperature and humidity in UK sheds on cow performance.

See also: 6 feed strategies to mitigate heat stress in cattle

Lallemand Animal Nutrition is working with Dr Tom Chamberlain, founder of Chalcombe, to monitor heat stress on four farms in south England.

One monitor will record temperature and humidity inside sheds, and the other on the grazing platform. These will monitor THI, as well as daytime heat stress index (DHI).

The data will be benchmarked against set parameters to give farmers a risk score of none, moderate, high and severe, as well as estimated yield loss.

About heat stress

Heat stress in cattle is likely to become a much bigger problem in England and northern Europe due to global warming raising average temperatures and making extreme events such as heatwaves more common.

On top of this, as dairy cow yields increase, they become more prone to heat stress.

“The biggest issue facing UK farmers when it comes to heat stress is that our cows aren’t adapted for higher temperatures.

“Because of this, and the fact that most of the data we have comes from hot countries, the threshold could be significantly lower than what we currently think,” explains Mark McFarland, feed additive product manager at Lallemand Animal Nutrition.

He adds: “This could mean that cows in the UK could experience heat stress at lower temperatures and humidity levels than cows in Argentina or Spain, for example. Consequently, the correlated drop in fertility and milk production could be happening much sooner than expected.”

Both sets of data will be freely accessible to dairy farmers, advisers and nutritionists via Cargill and Lallemand’s websites.

Results can already be viewed in real-time on the Lallemand website. Data will be published on Cargill’s website from early June.


Research from Cargill has shown that, in the UK, fertility can decline when temperatures exceed an average of 14C for the day (THI 57), and production can be affected when daily average temperatures exceed 22C (THI 68). THI levels will be higher inside cow sheds than outdoors by at least 2 THI points.