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Heat Abatement and Temperature Management

alternative practice names:

Heat Stress Control; Cow Cooling; Environmental Temperature Management; Ventilation; Air Exchange

Heat stress has a profound impact on dairy cows, leading to reduced feed intake, decreased milk production, impaired reproductive performance, and a decline in overall herd health. Heat abatement is any of a number of strategies to relieve the cows from the stress of these environmental conditions, typically using some combination of shade, air movement, and evaporative cooling:


  • Shade: This is the most common method for reducing heat stress. In open lot dairies, it can be as simple as suspending cloth overhead, while in confinement housing, barns naturally provide shade.

  • Fan installations: These facilitate air movement and increase convection, reducing environmental temperatures.

  • Cow evaporative cooling: This is highly effective in lowering core body temperatures in heat-stressed cows. This method involves soaking the cows with large-droplet water systems while maintaining air movement, which efficiently pulls heat away from the cow's body.

  • Barn evaporative cooling: This combines air movement with either small-droplet water systems near the fans or an evaporative cooling pad at the air inlet in barns with a negative-pressure ventilation system. This setup cools the air before it passes over the cows, enhancing overall cooling efficiency.


Sophisticated controls for fans, sidewall curtains, soakers, and other environmental controls, such as exhaust chimneys, have been developed to aid dairy managers in optimizing the benefits of this equipment. The most modern ones use inputs not only from thermostats but also from weather stations and even photosensors to keep cows cool and comfortable. 

When used, in what regions in the U.S. is the practice found: 

Northwest, West, Upper Midwest, Southwest, Northeast, Southeast

FARM SIZE 

When used, typically found on farms of the following sizes:

All Sizes

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Practice Benefits 

Improved cow performance: Research has consistently demonstrated that effective cow cooling significantly improves feed intake, milk production, and fertility outcomes. Heat stress can lead to a significant reduction in milk yield, with decreases of up to 35% reported due to lower feed intake and disrupted metabolic processes (Polsky & von Keyserlingk, 2017).


Improved reproductive performance: Heat stress negatively impacts reproductive efficiency by reducing conception rates and increasing the incidence of early embryonic loss (De Rensis & Scaramuzzi, 2013). Implementing cooling systems can help mitigate these effects, leading to improved fertility and better overall reproductive outcomes.


Reduced incidence of lameness: Heat stress can lead to increased standing time as cows seek to cool themselves by avoiding lying down, which puts additional pressure on their hooves and can exacerbate lameness. By implementing effective heat abatement strategies, farmers can encourage cows to lie down more frequently, reducing the strain on their hooves and lowering the risk of lameness (Cook et al., 2007).


Improved replacement performance: Prolonged exposure to heat stress can lead to epigenetic changes that alter gene expression, potentially affecting the development, productivity, and health of future generations of calves (Polsky & von Keyserlingk, 2017). Proper heat abatement helps prevent these epigenetic alterations, safeguarding the long-term health and productivity of both the current herd and future offspring.

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Implementation Insights

Site-specific or Farm-specific requirements 

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  • Climate considerations: The climate and housing system will govern which equipment is most appropriate for optimizing the cow environment. Some barns will need to be designed to keep cows comfortable in both subzero temperatures and heat stress conditions, and these will require different design characteristics.

  • Water availability: Additionally, water availability will increasingly influence how viable specific evaporative cooling strategies are by region.

Required Capital Expenditures (CapEx)

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  • Heat abatement equipment: Capital expenditure associated with ventilation and heat abatement equipment in dairy barns can be significant and vary substantially based on animal housing and climate. Fans, high-pressure misting systems, baffles, or adjustable sidewalls are common expenses.

  • Equipment controllers: While the initial cost of sophisticated equipment controllers can be high, these systems offer long-term savings by optimizing power usage, running fans, and other equipment only when necessary based on real-time conditions.

  • Three-phase power: Fans, in particular, can be energy-intensive, but upgrading to 3-phase power can enhance cow cooling and operational efficiency. 

Required Operational Expenditures (OpEx)

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  • Equipment maintenance: Fans should be cleaned and maintained regularly. Poorly maintained fans can lose 20 to 50% of their performance capacity, so a bi-annual maintenance check is generally recommended (University of Wisconsin School of Veterinary Medicine, n.d.). The maintenance on this equipment is very basic, involving cleaning, greasing, and simple troubleshooting for power outages or other malfunctions. When using automated sensors, any controller malfunctions will require assistance from specialized technicians or vendors.

  • Water use: Cooling systems require large volumes of water. Sprinkler systems can use between 215 and 454 L/cow per day (Means et al., 1992; Strickland et al., 1989). In regions with rising temperatures and limited freshwater supplies, this water use can increase operational costs. In addition, water associated with cow cooling may flow into manure store facilities and need to be managed.

Implementation Considerations

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  • Worker comfort: To avoid chilling workers, dairy farms often keep cattle too warm during the winter, which compromises air quality. In the summer, cooling systems are frequently not activated at sufficiently low temperatures, further affecting both cattle and worker comfort.

  • Winter ventilation: In colder climates, farmers strive to maintain warmer barns during winter, but this must be balanced with proper ventilation to ensure cow health. Adequate ventilation removes moisture, heat, and harmful gases like ammonia. Without it, ammonia levels can rise, posing health risks to both animals and handlers. Mechanical systems like exhaust fans and tunnel ventilation are crucial for maintaining air quality during winter, as natural ventilation alone may not suffice, particularly in tightly sealed barns designed to conserve heat.

  • Differing impact of heat stress: Lactating dairy cows are more sensitive to heat stress compared with non-lactating (dry) cows due to milk production elevating metabolism (Purwanto et al., 1990). Similarly, higher-yielding cows are more impacted by heat stress than lower-yielding animals (Spiers et al., 2004).

  • Micro-environments: Airflow and temperature are unevenly distributed within barns, making it essential to consider different microenvironments, especially in resting areas. Cows accumulate heat while lying down and dissipate it when standing, highlighting the need for targeted heat abatement strategies (University of Wisconsin School of Veterinary Medicine, n.d.).

  • Impacts of humidity: Many cooling systems for cows add moisture to the air, which can raise humidity levels. Proper ventilation is essential to prevent this increased humidity from exacerbating gas buildup and worsening heat stress. The temperature-humidity index (THI) is a key indicator of heat stress in dairy cows, with most research suggesting that heat stress begins at a THI of 72 or higher (De Rensis et al., 2015). In dry conditions, cows typically experience heat stress when temperatures reach the upper 80s Fahrenheit. However, in high humidity, heat stress can start at temperatures as low as 70°F.

  • Other technology-specific considerations:

    • Fans: For effective heat abatement, fans should direct air at speeds of 3.5-6 miles per hour, ensuring the airflow reaches cow level and covers as much of the cow-occupied area as possible. Slower air speeds can aid in air exchange but offer limited cooling through convection.

    • Soakers: The installation of feed lane soakers may lead to wetter alley conditions, which can increase the risk of mastitis in barns.

    • Evaporative cooling systems: While primarily used for temperature control, these systems can indirectly affect noxious gas levels. By keeping cows cooler and more comfortable, they may spend more time lying down, which can lead to less agitation of manure and reduced gas release.

Financial Considerations and Revenue Streams

There are no federal cost-share programs or conservation funding for this practice.

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Environmental Impacts

MAY REDUCE FARM GREENHOUSE GAS FOOTPRINT

Little scientific research directly evaluates the practice's impact on a farm's environmental footprint. However, heat stress abatement can improve feed intake,¹ milk production,¹ reproductive performance,² and animal health,³ which may reduce greenhouse gas (GHG) emissions per unit of milk (emission intensity).


See research highlights below:

  • Herzog et al. (2021) modeled the environmental impacts of implementing basket fans for heat abatement in dairy farms. They found that effective heat abatement reduces the negative impacts of heat stress on feed intake, milk production, and reproductive performance, which can improve feed efficiency and reduce CH₄ emissions per unit of milk produced. While fans do increase energy use, their ability to enhance cow productivity and health can lead to a net reduction in GHG emissions on a per-unit-of-milk basis by improving the overall efficiency of dairy operations.


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¹ When a cow experiences heat stress, it reduces its dry matter intake (DMI) as a coping mechanism, leading to fewer nutrients available for milk production (Rhoads et al., 2009). At the same time, the cow's basal metabolism increases due to the activation of its thermoregulatory system. This added metabolic demand, which can rise by 7 to 25% (NRC, 2001), worsens the metabolic stress and further decreases milk production.

² Heat stress negatively impacts reproductive efficiency by reducing conception rates and increasing the incidence of early embryonic loss (De Rensis & Scaramuzzi, 2003).

³ Heat stress can lead to increased standing time as cows seek to cool themselves by avoiding lying down, which puts additional pressure on their hooves and can exacerbate lameness (Cook et al., 2007).

REFerences

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Alignment with FARM Program

FARM Animal Care (AC) V5 Alignment

The FARM Animal Care program requires that all age groups of animals are provided with adequate protection from both heat and cold, ensuring their well-being under typical climatic conditions.

Contents

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We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights. 

We're always eager to update the website with the latest research, implementation insights, financial case studies, and emerging practices. Use the link above to share your insights. 

Contents

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Practice Overview

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Practical Insights.png
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Research Results.png
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Heat stress has a profound impact on dairy cows, leading to reduced feed intake, decreased milk production, impaired reproductive performance, and a decline in overall herd health. Heat abatement is any of a number of strategies to relieve the cows from the stress of these environmental conditions, typically using some combination of shade, air movement, and evaporative cooling:


  • Shade: This is the most common method for reducing heat stress. In open lot dairies, it can be as simple as suspending cloth overhead, while in confinement housing, barns naturally provide shade.

  • Fan installations: These facilitate air movement and increase convection, reducing environmental temperatures.

  • Cow evaporative cooling: This is highly effective in lowering core body temperatures in heat-stressed cows. This method involves soaking the cows with large-droplet water systems while maintaining air movement, which efficiently pulls heat away from the cow's body.

  • Barn evaporative cooling: This combines air movement with either small-droplet water systems near the fans or an evaporative cooling pad at the air inlet in barns with a negative-pressure ventilation system. This setup cools the air before it passes over the cows, enhancing overall cooling efficiency.


Sophisticated controls for fans, sidewall curtains, soakers, and other environmental controls, such as exhaust chimneys, have been developed to aid dairy managers in optimizing the benefits of this equipment. The most modern ones use inputs not only from thermostats but also from weather stations and even photosensors to keep cows cool and comfortable. 

Practices and technologies

Heat Abatement and Temperature Management

alternative practice name:

Heat Stress Control; Cow Cooling; Environmental Temperature Management; Ventilation; Air Exchange