Temperature and humidity monitoring to help dairy farmers tackle heat stress

Heat stress in dairy cattle can be a serious issue for farmers, affecting milk production, fertility and disease rates. As such it can have dire impacts on both farm finances and animal wellbeing. Cargill UK will install automated, cloud-based data loggers on 30 dairy units across the UK. Live readings will then be relayed by WiFi to a dedicated web page showing the temperature and humidity index (THI) by region, and in sheds for the selected farms. It will also give the average temperature and THI for the past 24 hours and the past week.

Mark Scott Nutritionist at Cargills

“This national data will be freely accessible to dairy farmers, their advisers and their nutritionists,” says Cargill ruminant lead Mark Scott. “This is an expansion of our work from 2020 which identified impacts of temperature and humidity on cow performance in a select number of UK herds where it was piloted.

“We are now taking the next step to create a reference point that will raise awareness of the conditions in cow sheds in summer and encourage discussions that will help to mitigate the effects of heat stress in UK dairy cattle.

“Our research work has shown that the combination of increasing temperatures and humidity – that is typically 60 per cent in the UK in summer – affects cow performance with fertility being the first ‘victim’. Fertility can decline when temperatures exceed average 14°C for the day (THI 57), and production can be affected when daily average temperatures exceed 22°C (THI 68). And it is worth noting that THI levels will be higher inside cow sheds than outdoors by at least two THI points.”

Cargill will also be using the THI information alongside herd fertility and production data to identify the real-time impact of temperature and humidity in UK sheds on cow performance.This data will help the UK’s dairy farmers improve animal wellfare and better plan for warm weather.

Dutch and German experience

THI data loggers in situ in cow sheds May 2021

Last summer, similar monitoring systems were installed on the continent. Cargill’s Netherlands-based ruminant team installed data loggers on 30 dairy farms in the Netherlands and 20 in Germany, to record the THI from May to September 2020 and reported it via their dedicated website.

“We defined three regions in each country and averaged the daily THI readings from loggers in those regions, then reported them through a designated web page,” says Cargill Netherlands adviser Nick van den Pol.

“We encouraged farmers to use it and we had more than 1,000 farmers regularly logging on in each country. It generated a lot of discussion on farm.

“Farmers were able to correlate dips in milk production and fertility blips with the THI data and this, they found, made the heat stress situation ‘real’,” he adds. “It also highlighted that humidity, as well as heat, plays a part in cow performance.

“They noted that the THI was above 60 for most readings throughout the summer – the threshold above which fertility can dip. And, sure enough, many farmers reported lower fertility levels during these months.”

Although the effects of heat stress have been supported with trial results from farms in Florida and other parts of the globe, Mr van den Pol found that the impact of heat on cow performance really ‘hit home’ when farmers could link temperatures in their own country with cow performance in their own herds.

The 2021 UK loggers are sure to generate interest and discussion, giving farmers real time access to data from across the country. In the long run, the information may help boost UK milk production.

The data will be going live from early June, and will be published on the Cool Cow web page