Cooling cows: how to manage cattle heat during hot summers

Introduction

Heat stress management in cattle can be critical, especially during hot summer months. Cattle, especially high-producing dairy cows, are vulnerable to high temperatures due to their high metabolic heat production. Signs of heat stress can include increased panting, drooling, decreased feed intake, and prolonged standing time. As global temperatures rise due to climate change, effective mitigation strategies are of high importance to ensure the health and welfare of our animals. In this article, we outline key areas to manage cattle heat stress, covering environmental modifications, nutritional adjustments, and technological interventions.

Environmental Strategies

One of the most interesting and effective ways to mitigate heat stress is altering and/or modifying the facilities on the farm in order to provide effective tools that minimize heat impact on cattle. Strategies may focus on decreasing solar exposure, promoting heat dissipation, and/or maximizing animal comfort. We will briefly go through some of these strategies.

1. Shades

Providing shade will help reducing solar heat exposure contributing to animal comfort and welfare. Cows have a low resistance to high temperatures and will be easily in heat stress if solar exposure is high. Cows that have access to shade are able to maintain lower rectal temperatures and respiration rates, which directly correlate with better milk yield and weight gain. Different shading options can include:

• Natural shade: Trees or silvopastoral systems provide sustainable and low-cost solutions but require long-term planning and enough area.
• Artificial shade: Metal or polyethylene shade cloths are commonly used. A shading material that blocks 80% or more of solar radiation is the best option.
• Portable shade: Especially beneficial for rotational grazing systems or paddocks; these structures can be moved according to needs.

Cows under shade will show increased lying time and reduced core temperatures compared to cows without shade access, particularly in grazing systems where solar exposure is higher.

2. Ventilation and Airflow Management

In confined systems with barns, ventilation is a cornerstone of heat control. Proper ventilation dilutes humid air, increases convective heat loss, and helps manage ammonia and other gases. This is something that should be considered when building the barn, since proper ventilation depends on prevailing winds and construction strategies. 

• Natural ventilation: Open-sided barns with a ridge vent and oriented to prevailing winds are effective. The “chimney effect” can enhance airflow in taller structures. This type of ventilation should always be present at any barn, regardless of heat stress management issues.
• Mechanical ventilation: High-speed fans, ideally ≥2 m/s, can cool animals effectively. Fan spacing and height should be optimized to prevent hot air pockets, and this will depend on the type of barn and placement of the vents.

Studies show that airflow of 1.5–2.0 m/s can reduce skin temperatures by up to 3°C (West, 2003). During extreme heat, fans alone may not suffice, requiring integration with evaporative cooling methods.

3. Evaporative Cooling Systems

These methods leverage water evaporation to absorb heat from the animal’s skin surface, significantly improving cooling efficiency. 

• Sprinkler systems: Apply large water droplets (not mist) directly to the cow's body for ~30–60 seconds, followed by 4–6 minutes of fan drying. This cycle mimics sweating in species with low evaporative cooling capacity.
• High-pressure misters: Common in arid zones, they cool the air rather than the animal directly. Their effectiveness drops in high humidity.
• Tunnel and cross ventilation: Used in closed barns with misting systems; it allows to control temperature and humidity with higher precision.

Studies show that sprinklers combined with fans can reduce respiration rates from 90 to below 60 breaths per minute, a clear indicator of improved thermal comfort.

4. Water Availability and Management

Water is not only a nutritional requirement but also a primary thermoregulatory tool. Heat-stressed cattle increase water consumption by up to 50%. Thus, cooling strategies must ensure ad libitum access to fresh water at all times:

• Water access: At least two water points per pen, with flow rates ≥10 L/min
• Provide shade: Prevent water from heating under direct sun. Water temperatures should remain below 25°C
• Regular cleaning: Prevent algae and pathogen buildup which reduce water quality and intake

There are some emerging technologies like cooling pads and hydrothermal flooring that are being used in high-value operations. These systems circulate cool water beneath resting surfaces or within rubber mats, offering localized cooling during lying periods—an important time for thermoregulation.

Nutritional Management

Ruminants, mostly due to the fermentation process, have a higher critical temperature range of 25-30ºC. Above this, heat stress alters nutrient metabolism and reduces dry matter intake (DMI). Adjusting diets can compensate for energy deficits and reduce metabolic heat production:

• High-quality forages will lead to a lower fermentation heat in the rumen.
• Feeding schedules should shift to cooler parts of the day (early morning, late evening) to encourage intake.

Genetic and Technological Solutions

Bos indicus breeds (e.g., Gir, Brahman) and crossbreds exhibit greater resilience due to their skin characteristics and metabolic adaptations. Breeding for heat tolerance is a long-term strategy. This can be a effective but it takes time, and should be carefully planned, especially in milk operations, where pros and cons should be evaluated.

Precision livestock farming tools are rapidly evolving and can provide interesting solutions —such as wearable sensors and thermal imaging—that allow early detection of heat stress. Widely used examples are automated misting and fan systems triggered by temperature, and image systems that allow the early identification of heat stress signs.

Take Home Messages

Cattle heat stress management should be multidisciplinary, combining environmental modifications, nutritional strategies, and technological innovations. With increasing climate variability, proactive and adaptive approaches are essential for maintaining animal welfare and farm productivity. Research is currently focussing on scalable, affordable solutions tailored to diverse production systems and geographies.

References

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