How do farmers in the Middle East reduce heat stress in their dairy cows?

Hot weather brings with it an extensive list of potential troubles for dairy producers, including heat stress. Cows are more vulnerable to heat stress because they generate so much body heat while producing milk.

Many issues can arise when cows are heat-stressed, including:

• A reduction in dry matter intake, leading to a considerable decrease in milk production.
• Reduced immune function and a higher somatic cell count.
• A decrease in conception rates, resulting in an increased calving interval.

To keep these problems at bay, it is crucial for dairy farmers to closely monitor their cows during periods of high heat and humidity in order to promptly identify any signs of heat stress. Recognizing the symptoms early and implementing the appropriate management strategies can help mitigate the negative effects of heat stress and improve the well-being of the cows.

Recognizing the onset of heat stress

The signs and symptoms of heat stress include:

• An elevated respiration rate
• Excessive drooling and panting
• Decreased feed intake
• Decreased milk production
• Behavioral changes
• Increased water consumption
• Elevated body temperature
• Reduced fertility
• Increased respiration effort
• Lethargy and depression

Heat-stressed cows exhibit altered behavior as a coping mechanism and to dissipate heat. For instance, they spend less time eating, ruminating, and engaging in social interactions, which can lead to reduced feed efficiency and nutrient utilization. They also spend more time standing up and less time lying down when heat-stressed because their core body temperature rises when they lie down. When they stand up, however, they can better dissipate heat, so their body temperature falls. Based on this behavior, a higher proportion of cows standing is yet another indicator of heat stress.

Moreover, during the hot season, dairy cows drink a lot of water to cool themselves. Along with drinking more water, heat-stressed cows often seek shade and any other means of cooling, leading to overcrowding and potential conflicts within the herd.

Keeping cows cool

The negative impacts of heat stress can be mitigated by adding nutrients that have a buffer effect on the diet.

According to the NASEM 2021 Nutrient Requirements of Dairy Cattle (page 128), it has been shown that feeding potassium at levels that exceed the animal's requirements can lead to heightened intake and milk yield in cows experiencing heat stress. A dietary potassium concentration of 1.5% (on a dry basis) during heat stress has also been shown to maximize lactation performance.

To alleviate the negative impacts of heat stress on dairy cows, proactive measures must be taken. Those measures can include:

• Providing adequate housing and ventilation. Well-designed barns that feature the proper ventilation and cooling systems offer cows a comfortable environment.
• Giving cows access to shade and water. Ensuring that cows have access to shaded areas and an abundant supply of cool, clean water throughout the day helps them regulate their body temperature.
• Maintaining proper nutritional management. Adjusting the cows’ diet to meet their increased energy demands during periods of heat stress can help them maintain milk production and reduce the incidence of metabolic disorders.
• Heat-abatement strategies. Employing techniques and tools such as misting, fans, and sprinkler systems in barns and outdoor areas can help cows cool down and minimize the effects of heat stress.

Heat Stress in the Middle East

The climate of the Middle East is generally hot and arid or semi-arid. In the summer, daytime temperatures can reach over 52°C!

This excessive heat is compounded by rising humidity and, additionally, the temperature humidity index (THI). As illustrated in Figure 1, when the THI exceeds 72, cattle begin to experience heat stress.

We have met with farmers in the Middle East to discuss and learn how they manage this difficult period of the year. Read on to see their answers to some questions about operating a dairy farm in the face of heat stress.

When does heat stress occur?

Heat stress generally first manifests around the end of June and remains a problem until the end of September in the Middle East. Signs of heat stress in dairy cows are noticeable when the temperature reaches 21°C — and as soon as the thermometer exceeds 22°C, cattle leave their thermal comfort zone.

The issues and discomfort from high temperatures are only compounded by humidity, which farmers call “the real problem”. Cows cannot bear a high level of humidity, which is an issue, as it is unavoidable. Even though the cooling systems used widely across the Middle East can drop the temperature to around 20°C, which is ideal for cows, the level of humidity remains high.

Some people might think that summer rains could offer a respite — but Middle Eastern dairy farmers know different, it is exactly the opposite. Rain in the desert can lead to flooding issues and increases the humidity level — and despite what people may think, it does not really cool down the temperature.

How much do cows increase their water intake during the heat?

The water consumption of cows during the summer months is often double their intake levels during the winter — or more. In the Middle East, farmers use approximately 400 liters of water per cow in the winter; in the summer, that amount increases to 1,000 liters per cow.

If cows have free access to water fountains, they can drink water whenever they want, allowing them to stay cool. But farmers must provide more water than just what cows will drink: a substantial amount is also used for the engine cooling system and in showers stalls, which are another way to fight heat stress.

What solutions help reduce the stressful effects of heat on cows?

The main goal is to keep cows comfortable, and fortunately for farmers, there are plenty of ways to do that, including:

• Offering water fountains, fans, and sprayers
• Insulating roof barns to prevent heat penetration
• Placing giant fans around the farm under which the animals can come to rest
• Providing plenty of shaded areas

On one farm in the Middle East, right after the cows finish milking, they take a shaded walkway into the shower stall area, which “they love”. Afterward, they often choose to sit in a shadowy area, where they can rest until it’s time for milking again. All these options can help keep heat stress from impacting production and reproduction — arguably, the two most important aspects of dairy farming.

How do you control the heat in your cattle herd?

Some farmers in the Middle East keep the heat under control through computerized systems, which keep the environment temperate: As the temperature rises, for instance, adjustments are triggered automatically, so the amount of water available for cows might increase as well. Additionally, farmers occasionally place sensors on their cows to control their temperature and solve the problem on their own.

Middle Eastern dairy producers also sometimes give their cows the freedom to go where they want, and the cows use that freedom to their benefit. Often, for instance, in the hotter months of July and August, the cows prefer to stay outside at night, when it is cooler.

Have you found that feed additives can help reduce heat stress?

Summer is a high-risk season. As such, many farmers strive to give their cows the very best nutrition during this period, including high-quality forage and increased levels of important trace minerals and elements, such as yeast culture, including Yea-Sacc from Alltech.

Selecting strains of yeast have been shown to support reproduction in cows — so it stands to reason that, if consumption of this important ingredient diminishes as a result of the impact of heat stress, farmers will reap the (negative) consequences over the next year.

Milk production can also feel the effects of heat stress. If production begins to drop, farmers may adjust the amount of supplemented elements and trace minerals in the ration for better results.

Of course, having support never hurts. The Alltech team in the Middle East works to assist dairy farmers in any way that they can, including by providing data and insights that help producers make the necessary decisions to keep their operations profitable and efficient under any circumstances, including during times of increased heat stress.

Heat stress poses significant challenges to the welfare, productivity, and sustainability of dairy cows. As temperatures continue to rise due to climate change, it is imperative for dairy producers, industry stakeholders, and policymakers to prioritize the implementation of heat-stress mitigation strategies on-farm. By investing in cow comfort and welfare, we can help turn summer in the Middle East into a “non-event,” thereby ensuring the well-being of dairy cows, enhancing milk production, and securing the future of the dairy industry.