Heat stress insights protect cow welfare and productivity

On the heels of England’s hottest June on record, managing heat stress remains a priority for dairy units. Monitoring in-shed conditions using the Temperature-Humidity Index (THI), can help overcome summer challenges and reduce the effects on herd health and productivity.

Rising temperatures

Weekly summary reports, compiled using data from Galebreaker and Phibro Health’s online THI-Live tool between 9 June to 6 July, reveal troubling trends in cow comfort, as much of the UK experienced two heatwaves in a matter of weeks.

Average shed temperatures reached concerning levels, with some regions recording peaks over 30°C.

Worryingly figures from mid-Wales and the south of England showed THI exceeded 80, a threshold that signals severe heat stress. The south and the Midlands faced persistent heat stress, with the average THI remaining above 65 for most of June.

In these areas, cows experienced increased respiration rates, reduced standing and lying times, and greater water consumption, all indicative of severe discomfort.

Galebreaker’s animal welfare specialist, Chloe Rodriguez, urges dairy farmers to remain vigilant when critical THI thresholds are exceeded regularly.

“Prolonged heat stress not only impacts cow welfare it can severely affect conception rates. While decreased Dry Matter Intake (DMI) during hot weather negatively influences milk yield, quality, and overall profitability,” says Ms Rodriguez.

“These effects may not become apparent until several weeks later when cows are tested for conception or milk quality, by which time it’s too late to address.

“Fortunately, adjusting management practices in anticipation of hot and humid conditions can help to mitigate these impacts."

Mitigation strategies

Regularly monitoring THI and prompt action are the best ways to diminish heat stress and protect cows from its worst effects. Recommendations to improve animal welfare include ensuring sheds are properly ventilated to regulate airflow.

Having access to a supply of fresh water will help prevent dehydration. Similarly, adjusting feeding schedules to take advantage of cooler overnight temperatures encourages greater intakes so cows have adequate nutrition. This can also be supplemented with feed additives designed to improve water retention.

Long-range outlook

The Met Office’s long-range forecast indicates continued extreme weather conditions, as in-shed temperatures are expected to rise again as we move towards late summer. With the current trend of high THI readings likely to persist well into August and September, dairy farmers are advised to remain proactive in their management strategies.

“Extreme heat events are becoming more frequent and intense – the dairy sector needs to prepare itself for the inevitable.

“With the right interventions, the impact of heat stress can be alleviated. Galebreaker is supporting farmers with data and advice to help protect herds and maintain productivity during the warmer months ahead," concludes Ms Rodriguez.