As UK summers grow warmer, heat stress in cattle is becoming a critical concern for farmers. Elevated temperatures combined with high humidity can significantly reduce feed intake, lower milk yields and impact fertility – particularly in dairy herds.

Kathryn Thompson :: Thursday 3rd July 2025 :: Latest Blog Posts

Summer Feed Tips to Combat Heat Stress in Cattle

As UK summers grow warmer, heat stress in cattle is becoming a critical concern for farmers. Elevated temperatures combined with high humidity can significantly reduce feed intake, lower milk yields and impact fertility – particularly in dairy herds. But it's not just milking cows at risk; dry cows and youngstock also suffer in the heat. Recognising the early signs of heat stress and taking preventative steps is essential. At BW Feeds, we believe nutrition plays a pivotal role in livestock resilience. Let's explore practical feeding and management strategies to help keep your animals cool, hydrated and healthy this summer.

Understanding the Impact on UK Cattle

Heat stress isn't just a concern for warmer climates – it's a growing issue for UK herds, particularly as summers become more unpredictable. Even at temperatures as low as 22°C, combined with high humidity, cattle can begin to suffer. This is because cows have a narrow comfort zone, and when the Temperature–Humidity Index (THI) rises above 72, performance starts to decline.

In dairy cattle, the effects are especially noticeable. Cows reduce their feed intake to limit metabolic heat, which leads to a drop in milk production and can cause weight loss. Fertility is also compromised, with lower conception rates and increased early embryonic loss. Even dry cows aren't exempt – heat stress during the dry period can impact future lactation performance and calf health.

For housed herds, the problem can be intensified by poor ventilation, solar gain through skylights, and limited access to water. Outdoor cattle aren't immune either – lack of shade and warm overnight temperatures can leave animals unable to cool down properly.

Understanding how heat stress affects UK cattle is the first step toward prevention. The good news? With the right strategies in place – especially around feed and water management – producers can minimise these impacts and support herd health all summer long.

Feed & Nutritional Strategies

Optimise Feed Timing & Frequency

During hot weather, cows tend to eat less – especially during the warmest parts of the day. To maintain intake and limit stress, it's essential to adjust feeding schedules. Aim to offer fresh feed early in the morning and later in the evening, when temperatures are cooler and cows are naturally more inclined to eat. This can help maintain rumen function and support consistent energy intake. Pushing up feed regularly and refreshing rations throughout the day prevents spoilage and encourages consumption. These simple changes can make a noticeable difference to both appetite and overall cow performance during summer.

Adjust Ration Composition

When cattle are heat-stressed, their digestive efficiency drops, and fermenting high-starch feeds can generate excess internal heat. To counter this, consider adjusting your summer ration. Replacing some starch with rumen-protected fats helps maintain energy levels without increasing the heat load. High-quality, easily digestible forages should take priority, as poor-quality fibre can reduce intake further. Adding live yeast or rumen buffers can also support rumen health and stabilise pH levels under stress. Don't forget mineral balance – boosting potassium, sodium and magnesium helps maintain hydration and support muscle function. A tailored ration is a key defence against heat-related performance losses.

Add Feed Additives

Strategic use of feed additives can give cattle a crucial edge during periods of heat stress. Ingredients like niacin and betaine support cellular hydration and improve the body's ability to manage heat. Antioxidants help reduce the oxidative stress that often accompanies hot weather, while yeast cultures promote stable rumen conditions. These additives work best as part of a comprehensive summer nutrition plan, giving your herd the tools to stay productive, healthy, and more comfortable when temperatures rise.

Water & Cooling Management

Hydration is the cornerstone of managing heat stress in cattle. As temperatures rise, water requirements increase dramatically – lactating cows may drink over 100 litres per day. It's vital to provide clean, cool water at all times, ideally below 20°C. Ensure multiple troughs are available, positioned no more than 20?metres from feeding and resting areas, with one trough per 20 cows to prevent crowding. Regular cleaning is essential to avoid algae and biofilm build-up, which can deter drinking.

Providing shade is equally important, especially for outdoor cattle. Trees, shade cloths or purpose-built shelters can reduce heat load and encourage lying behaviour. For housed cattle, improving airflow through natural or mechanical ventilation can significantly reduce indoor temperatures. Consider using high-volume, low-speed fans to enhance air circulation, especially above feed passages and lying areas.

Where possible, install sprinkler systems or misters to support evaporative cooling. A typical cycle – 3 minutes on, 12 minutes off – can effectively lower skin temperature without soaking cows or bedding. These methods not only improve cow comfort but also help sustain feed intake, fertility and milk production during the hottest months.

Together, effective water access and cooling systems form the backbone of any heat stress prevention plan.

Housing & Handling Adjustments

The way cattle are housed and handled can have a major influence on how they cope with summer heat. In sheds or cubicle housing, airflow is crucial. Opening sidewalls and ridge vents and providing well-placed fans can help move warm, humid air out of the building. Aim for a consistent airspeed of around 10?km/h across the cows' backs to aid cooling. Avoid blocking airflows with equipment or poorly placed partitions.

When it comes to handling, timing is everything. Carry out routine tasks like milking, hoof trimming or veterinary checks during the coolest parts of the day – early morning or late evening. Prolonged standing in collecting yards during peak heat adds unnecessary stress and can suppress milk yield.

Finally, don't overlook dry cows and close-up heifers. They are just as vulnerable and deserve the same heat mitigation strategies to protect future productivity.

Monitoring & Action Steps

Staying ahead of heat stress starts with regular monitoring. Installing THI sensors in key areas of the housing – especially above feed and loafing areas – can help identify when your herd is at risk. A THI above 72 is the warning sign to take action.

Watch for behavioural and production indicators too. Reduced feed or water intake, increased panting, more time standing, and a drop in milk yield all suggest rising heat stress. Fertility issues – like delayed heats or lower conception rates – can also be a consequence. Keep an eye on rumen fill and dung consistency as signs of digestive stress.

Work closely with your nutritionist or vet to adapt rations and management practices as conditions change. Proactive adjustments can make all the difference in keeping cows productive and comfortable through the hottest periods.

Need help preparing your herd for summer? Get in touch with BW Feeds today to discuss tailored heat stress solutions – from custom rations to on-farm support. Let's make sure your cows stay cool, hydrated and productive all season long.