Feedlot Summer Heat Stress Facility Adjustments

By Dr. Zubair Khalid, DVM, MS, PhD · 2026-08-14

Key Takeaways

• Provide a minimum of 2 to 3 inches of linear shade per animal, with north-south orientation maximizing midday coverage and 10-12 feet of height promoting airflow.
• Ensure 2 to 3 inches of linear water tank space per animal with a refill rate of at least 10-15 gallons per minute, and keep water cool and clean to encourage intake.
• Orient pens and windbreaks to align with prevailing summer winds, avoiding solid structures that trap heat and instead utilizing slatted or open designs.
• Maintain dry, well-drained pen surfaces with a 2-4% slope and mounds at least 8-10 feet high to facilitate air movement and reduce humidity at cattle level.
• Utilize sprinklers for 1-2 minute cycles every 30-60 minutes in dry conditions, ensuring cattle are dry before nightfall to prevent heat trapping.
• Shift 70% or more of daily feed rations to cooler evening hours, supported by adequate lighting in feed alleys and frequent bunk cleaning to prevent spoilage.

Summer heat takes a heavy toll on feedlot cattle. When the temperature climbs and humidity holds the heat close, cattle eat less, gain slower, and face a real risk of heat stress illness or death. This guide explains how to adjust your feedlot facilities to reduce heat load on your cattle and keep them performing through the hottest months. It is written for feedlot owners, managers, and crew leads who want practical steps they can take without waiting for an emergency.

The focus here is on the facility side of heat stress management. That means shade, water supply, pen surface, mounds, wind management, sprinklers, feed bunk management, and the routines that make those systems work. You will also find guidance on monitoring cattle and knowing when to call for professional help.

At a Glance

• Provide at least 2 to 3 inches of linear shade per animal in the pen. More is better during extreme events.
• Water is the single most important facility factor. Aim for 2 to 3 inches of linear tank space per animal and check flow rates daily.
• Orient shade and windbreaks to match your prevailing summer winds. Blocking wind is a mistake in hot weather.
• Keep pen surfaces dry and well drained. Mud and manure pack hold heat and increase humidity at cattle level.
• Use sprinklers only when they can dry cattle off before nightfall. Wet cattle overnight lose their ability to shed heat.
• Feed 70 percent or more of the daily ration in the cooler evening hours. Adjust facilities to support night feeding.
• Have a written heat event plan with clear thresholds for when you change feeding time, add sprinkling, and start close monitoring.
• Record daily temperature, humidity, wind speed, and cattle behavior so you can spot problems before cattle show severe signs.

Understanding Heat Stress in Feedlot Cattle

Cattle generate a large amount of body heat from digestion and muscle activity. Feedlot cattle on a high energy ration produce even more internal heat than cattle on pasture. They must release that heat to the environment to keep their body temperature in a safe range. When air temperature, humidity, and solar radiation combine to make heat release difficult, the animal becomes heat stressed.

The main ways cattle lose heat are radiation, convection, conduction, and evaporation. Radiation and convection work when the air around the animal is cooler than the animal's skin. Conduction works when the animal touches a cooler surface. Evaporation works through sweating and panting, but it only works well when humidity is low. In high humidity, sweat does not evaporate quickly, so cattle lose their most effective cooling mechanism.

Feedlot heat stress is not just about air temperature. Solar radiation adds a significant heat load directly to the animal. A black hided steer standing in full sun on a 95 degree day absorbs far more heat than the air temperature alone suggests. Wind speed matters too. A gentle breeze helps carry heat away from the animal. Calm conditions trap heat around the animal and make every other cooling measure less effective.

Humidity is the other major factor. The temperature humidity index, or THI, combines temperature and humidity into a single number that predicts heat stress risk. A THI of 75 is considered mild stress for most cattle. A THI above 80 is moderate stress. A THI above 84 is severe stress and above 86 is emergency conditions for feedlot cattle. Many feedlots track THI rather than temperature alone because it gives a more accurate picture of the danger.

Cattle breed, color, and body condition affect heat tolerance. Black cattle absorb more solar radiation than light colored cattle. Heavy cattle with high body condition scores have more insulation and generate more metabolic heat. Cattle that are already sick or recovering from previous illness handle heat poorly. Calves new to the feedlot are also at higher risk because they have not adapted to the ration or the environment.

The effects of heat stress show up in performance before they show up in obvious distress. Cattle that are mildly heat stressed eat less. They stand instead of lying down. They bunch together in shade or around water tanks. They reduce their activity to conserve energy. All of these behaviors reduce gain. In severe cases, cattle pant heavily, drool, and show signs of distress that can progress to death.

Facility design and management can reduce heat load by 10 to 20 percent or more compared to an unmodified pen. That reduction can be the difference between cattle that keep eating and cattle that lose condition or die. The sections that follow walk through each facility adjustment in practical detail.

Shade Design and Placement

Shade is the most direct way to reduce solar radiation on feedlot cattle. A well designed shade structure can reduce the heat load on cattle by 30 to 50 percent compared to full sun. The key is to provide enough shade, place it correctly, and build it so it does not create new problems.

How Much Shade to Provide

The common recommendation is 20 to 40 square feet of shade per animal. For a pen with 100 head of 1,000 pound cattle, that means 2,000 to 4,000 square feet of shade. A simpler rule of thumb is 2 to 3 inches of linear shade per animal along the shade structure. A 100 foot shade structure provides 1,200 inches of linear shade, which covers 400 to 600 head at the minimum rate.

More shade is better during extreme heat events. If you can provide 40 square feet per animal, do it. The cost of the structure is offset by improved gain and reduced death loss during the hottest periods. If you cannot build permanent shade for all pens, prioritize the pens with the highest risk cattle. Heavy cattle, black cattle, and newly arrived cattle should get shade first.

Shade Orientation and Height

The orientation of your shade structure affects how much of the day it protects cattle. A north south oriented shade structure casts a shadow that moves from west to east across the day. This provides good coverage during the hottest part of the day when the sun is high. An east west oriented structure casts a shadow that stays fairly stationary but can be short at midday.

For most feedlots, a north south orientation works best. The shade moves across the pen through the day, which also helps keep the ground from becoming completely bare and dusty. If you have prevailing afternoon winds from a consistent direction, you can angle the shade slightly to capture more breeze under the structure.

Height matters for two reasons. First, cattle need clearance to stand under the shade. A shade that is too low discourages cattle from using it. Second, shade that is too low traps heat and reduces air movement. A height of 10 to 12 feet at the lowest edge works well for most feedlot cattle. Higher shades of 14 to 16 feet allow better air movement but cast less defined shade.

Shade Roofing Materials

The roofing material affects both the quality of shade and the heat load under the structure. Solid metal roofs provide complete shade but can radiate heat downward as they warm. Insulated metal panels reduce this radiant heat. Shade cloth with 80 to 90 percent shade factor provides good shade while allowing some air movement through the material.

Polypropylene shade cloth is a common choice because it is lighter than metal and easier to install on simple frames. It also does not radiate as much heat downward as a hot metal roof. The tradeoff is that shade cloth needs periodic replacement as it degrades in sunlight. Plan on replacing shade cloth every 5 to 10 years depending on quality.

If you use solid metal roofing, consider a white or light colored finish. Light colors reflect more solar radiation and keep the underside cooler. A white roof can reduce the temperature under the shade by several degrees compared to a dark roof.

Shade Placement Within the Pen

Place shade so cattle can access it without crowding. The shade should be in an area with good drainage so the ground underneath does not become muddy. If you also use sprinklers, do not place shade directly over the sprinkler zone. Wet ground under shade creates humidity and mud that works against cooling.

Consider the location of water tanks when placing shade. Cattle naturally move between shade and water. If shade is far from water, cattle may not use either as much as they should. Place shade within 50 to 100 feet of water tanks when possible.

Portable Shade Options

If you cannot build permanent shade, portable options can help during extreme heat events. Portable shade panels and temporary shade cloth structures can be set up in high risk pens. These are not as durable as permanent structures but they can provide critical relief during a heat wave.

Portable shades also let you move shade to pens that need it most. If you have a group of heavy cattle in a pen without shade and a heat event is forecast, you can set up temporary shade in that pen. The flexibility is useful but plan ahead. Portable shade sells out quickly when a heat wave is forecast.

Water Supply and Tank Management

Water is the most critical input for heat stressed cattle. Cattle lose water through sweating and panting as they try to cool themselves. A heat stressed 1,000 pound steer can drink 25 to 30 gallons of water per day, nearly double its normal intake. If water supply is limited, cattle cannot cool themselves and will reduce feed intake even more.

Water Tank Space and Access

The standard recommendation is 2 to 3 inches of linear tank space per animal. A tank that is 10 feet long provides 120 inches of linear space, which serves 40 to 60 head. For a 100 head pen, you need 200 to 300 inches of tank space, which means a tank at least 17 to 25 feet long or multiple tanks.

During heat events, cattle crowd around water tanks. If tank space is limited, dominant cattle push subordinate cattle away. The cattle that need water most may not get access. Adding extra temporary tanks during heat events can relieve this pressure. Even a large livestock watering tub set up temporarily can help.

Water Flow Rate

Tank space is useless if water does not flow fast enough to keep up with demand. A single 1,000 pound steer can drink 3 to 4 gallons per minute when it is thirsty. A pen of 100 heat stressed cattle can drain a 500 gallon tank in minutes if flow is slow.

Check the flow rate to each tank during hot weather. A good rule is that each tank should refill at a rate of at least 10 to 15 gallons per minute. If flow is slower, cattle may empty the tank and wait for refill. That waiting time reduces water intake and increases competition.

Test flow rate by timing how long it takes to fill a 5 gallon bucket. If it takes longer than 20 to 30 seconds, the flow is too slow for a large pen. Check for kinked hoses, clogged filters, or undersized lines. During heat events, consider running a supplemental hose or temporary tank into high risk pens.

Water Temperature

Cattle prefer cool water and drink more of it when it is cool. Water sitting in an unshaded tank can reach 80 to 90 degrees on a hot day. Cattle drink less warm water, which compounds the heat stress problem.

Shade over water tanks helps keep water cooler. You can also use tanks with light colored interiors that reflect sunlight. Some feedlots use floating covers or shade balls on water tanks to reduce heating. These are inexpensive and effective.

If you have a well or piped water source, the incoming water is often cooler than the air temperature. The issue is heating in the tank. Consider larger tanks that hold more water so the water has more thermal mass and heats more slowly. A large tank also provides a buffer if flow is interrupted.

Water Quality

Cattle drink less water that tastes or smells bad. Algae growth in tanks is common in summer and can reduce water intake. Clean tanks regularly, especially during hot weather. A scrub brush and a mild bleach solution work well. Rinse thoroughly after cleaning.

Check for mineral buildup and sediment in tanks. These can affect taste and reduce intake. If you have hard water, plan on more frequent tank cleaning during summer. Also check that automatic waterers are functioning correctly. A stuck float valve can either overflow the tank or leave it empty.

Pen Surface and Mound Management

The surface cattle stand on affects how much heat they absorb and how well they can cool themselves. A dry, well drained pen surface is cooler and more comfortable than a wet or muddy one. Mounds give cattle a place to rest that is higher and drier with better air movement.

Drainage and Pen Slope

Good drainage is essential for summer heat management. Standing water and wet manure create humidity at cattle level and make it harder for cattle to shed heat. The pen should slope away from the feed bunk and water tanks so water does not pool in high traffic areas.

A slope of 2 to 4 percent is typical for feedlot pens. That means a drop of 2 to 4 feet per 100 feet of pen length. Check that drainage ditches and outlets are clear before summer. A blocked drainage system can turn a dry pen into a mud hole after a single rain event.

Mound Design

Mounds are raised areas in the pen that provide cattle a dry place to lie down and stand. They are particularly valuable in summer because they are usually higher than the surrounding pen surface, which means better air movement and less humidity at cattle level.

Build mounds at least 8 to 10 feet higher than the surrounding pen surface. A mound that is too low does not provide enough elevation benefit. The mound should be large enough that a significant portion of the pen's cattle can use it at once. A rule of thumb is that mounds should cover 10 to 20 percent of the pen area.

The top of the mound should be crowned so water runs off. A flat topped mound collects water and becomes muddy. The sides should be sloped gently enough that cattle can walk up easily. A slope of 3 to 1 or flatter works well.

Maintaining Dry Surface

During summer, scrape pens regularly to remove manure buildup. Manure pack holds moisture and generates heat as it decomposes. A thick manure pack can also insulate the ground and keep it warm through the night, which reduces the nighttime cooling that cattle need.

Plan to scrape pens before summer starts and again mid summer if manure buildup is significant. The manure removed in summer is also valuable as fertilizer, so there is a financial benefit to regular scraping.

If a pen becomes dusty, that is a separate problem. Dust can irritate cattle lungs and reduce feed intake. Sprinkling for dust control is acceptable, but be careful not to create mud. The goal is a dry, firm surface that does not generate dust clouds when cattle move.

Wind Management and Airflow

Air movement is one of the most effective cooling mechanisms for cattle. A gentle breeze carries heat away from the animal and helps evaporate moisture from the skin. Facility design can either help or hurt airflow through the pen.

Understanding Prevailing Winds

Know your prevailing summer wind direction. In many regions, summer winds come from the south or southwest. Orient your pens, shade, and windbreaks so that these winds flow through the pen rather than being blocked.

A pen that is sheltered from summer wind will be significantly hotter than an exposed pen. Cattle in sheltered pens pant more, eat less, and show more heat stress. If you have pens in a sheltered location, consider whether you can open up the pen to more airflow.

Windbreaks in Summer

Windbreaks are essential in winter to protect cattle from cold wind. In summer, they can be a liability. A solid windbreak that blocks summer breezes traps heat in the pen. If you have permanent windbreaks, consider how they affect summer airflow.

You have several options. You can build windbreaks that are partially open, such as slatted fences that block winter wind but allow some summer airflow. You can also build removable windbreak panels that come down in summer. Some feedlots use living windbreaks of trees, which allow more airflow than solid walls.

If windbreaks are causing heat problems in summer, the simplest fix is to remove or open them during the hottest months. If that is not possible, prioritize shade and water improvements in those sheltered pens.

Pen Orientation

The long axis of the pen should be oriented to maximize exposure to prevailing summer winds. If your prevailing wind is from the south, the long axis of the pen should run north south so wind flows through the length of the pen. This is the opposite of the orientation you might choose for winter wind protection.

If your existing pens are oriented poorly for summer wind, you can still improve airflow with other measures. Removing solid windbreaks, raising shade height, and avoiding solid fences between pens all help. Solid fence lines between pens can block airflow. Consider replacing solid dividers with pipe or cable fencing where possible.

Using Fans in Extreme Heat

In extreme heat events with calm conditions, some feedlots use large fans to force air movement through pens. These are typically high volume low speed fans mounted on poles or trailers. They are expensive to run but can be lifesaving during a severe heat wave.

Fans work best when they move air across cattle that are wet or that have access to water. The combination of wet skin and moving air creates evaporative cooling. If you use fans without wetting cattle, the effect is much smaller.

Fans are a temporary measure for extreme events, not a permanent solution. If you are considering fans, have a plan for where to place them and how to power them before the heat event arrives. Extension agents can help you think through fan placement for your specific pen layout.

Sprinklers and Evaporative Cooling

Sprinklers can be an effective cooling tool when used correctly. The key is that water must evaporate to cool the animal. Wet cattle that do not dry off are not being cooled. In fact, wet cattle in high humidity can be worse off because the water traps heat against the skin.

When Sprinklers Work

Sprinklers work best in hot, dry conditions with low humidity. The water wets the cattle, then evaporates, pulling heat from the animal. In dry climates, sprinkling for 1 to 2 minutes every 30 to 60 minutes can provide significant cooling.

In humid conditions, sprinklers are less effective. The water does not evaporate quickly, so cattle stay wet and the cooling effect is reduced. In very humid conditions, sprinklers may do more harm than good. Monitor humidity before deciding to use sprinklers.

Sprinkler Placement and Design

Place sprinklers so they wet the cattle's back and sides, not just the ground. Sprinklers mounted on poles 8 to 12 feet high with a spray pattern that covers the cattle body work best. Sprinklers that only wet the ground create mud and humidity without cooling cattle.

Do not place sprinklers over the feed bunk. Wet feed spoils quickly and cattle will not eat it. Also avoid placing sprinklers directly over water tanks, as the spray can contaminate the water or scare cattle away from drinking.

The sprinkler zone should be in an area with good drainage. Wet ground under sprinklers becomes muddy quickly. If possible, use a sprinkler zone on a mound or well drained area where water runs off.

Sprinkler Timing

The critical rule for sprinklers is that cattle must be dry before nightfall. Wet cattle overnight cannot shed heat effectively because the water traps heat against the skin. They also lose the ability to cool through the night, which is when they need to recover from the day's heat.

A typical sprinkling schedule is 1 to 2 minutes of spray every 30 minutes during the hottest part of the day. The goal is to wet the cattle, let the water evaporate, and then wet them again. If cattle are still wet from the previous cycle, you are over watering.

Stop sprinkling at least 2 to 3 hours before sunset. This gives cattle time to dry off before night. In high humidity conditions, stop even earlier. Watch the weather forecast. If a cool front is moving in, you may not need sprinklers at all.

Sprinkler Maintenance

Sprinklers need regular maintenance to work when you need them. Check nozzles for clogs, check spray patterns for coverage, and verify that timers are working. A sprinkler system that fails during a heat event is worse than no sprinkler system because you planned around it.

Test the entire system before summer starts. Run each zone and confirm coverage. Check that water pressure is adequate. Clean filters and screens. Have spare nozzles and parts on hand. During summer, inspect the system weekly and after any storm that could damage components.

Feed Bunk Management and Facility Adjustments

Feed management is a major part of heat stress control, and the facility needs to support the feeding strategy. Cattle naturally reduce feed intake during hot weather. The goal is to encourage them to eat during cooler periods and to keep the ration fresh and palatable.

Shift Feeding to Cooler Hours

The single most effective feeding change for summer is to deliver a larger portion of the ration in the evening. Cattle are naturally more inclined to eat in the cooler evening and early morning hours. By feeding 70 percent or more of the daily ration in the evening, you encourage intake when cattle can handle the heat load of digestion.

Facility adjustments support this strategy. Make sure feed alleys are lit well enough for night feeding. Have enough feed trucks and crew to deliver feed in the evening. If you currently feed mostly in the morning, shift gradually over a week or two so cattle adjust to the new schedule.

Bunk Management

In hot weather, feed in the bunk spoils faster. Spoiled feed is unpalatable and cattle will sort through it, eating the desirable parts and leaving the rest. This reduces total intake and creates waste.

Clean bunks more frequently in summer. Remove uneaten feed before it spoils. If you feed once daily, consider feeding smaller amounts more often to keep the bunk fresh. Some feedlots feed 60 percent in the evening and 40 percent in the morning to keep feed fresh through the day.

Adjust bunk management to the heat. If cattle are not cleaning up the bunk, reduce the amount fed. Overfeeding in hot weather leads to waste and reduces the freshness of the ration. The goal is to keep feed in front of cattle but not so much that it sits and heats.

Ration Considerations

Ration formulation is a nutritionist's job, but facility managers should understand the basics. High fiber rations generate more heat during digestion than high concentrate rations. However, you cannot simply reduce concentrate in summer without losing gain. The goal is to maintain energy intake while managing heat load.

Your nutritionist may adjust the ration during summer to include more digestible fiber, added fat, or specific additives that help with heat stress. Support these changes by ensuring feed is mixed correctly and delivered fresh. A ration that sits in the bunk and heats will not perform as designed.

Water Access Near the Bunk

Cattle need water close to the feed bunk, especially when they are eating. Digestion generates heat, and cattle drink to cool themselves and aid digestion. If water is far from the bunk, cattle may not drink enough after eating.

Place water tanks within 100 feet of the feed bunk when possible. During heat events, consider adding a temporary tank near the bunk in high risk pens. Some feedlots use water troughs along the bunk line so cattle can drink while eating. This is an effective way to support intake in hot weather.

Monitoring Systems and Recordkeeping

You cannot manage what you do not measure. A simple monitoring system tells you when heat stress is building and whether your facility adjustments are working. The system does not need to be expensive or complicated.

Track Temperature Humidity Index

The temperature humidity index is your primary monitoring tool. You can calculate THI from temperature and relative humidity using a simple chart or online calculator. Many weather apps and agricultural weather stations provide THI directly.

Check THI at least twice daily during summer, and more often during heat events. Record the morning and afternoon THI for each day. This record shows you when conditions are approaching dangerous levels and helps you plan facility adjustments.

The thresholds are important. A THI below 75 is generally safe. At 75 to 78, start watching cattle closely. At 79 to 83, implement your heat event plan. Above 84, take emergency measures and monitor cattle continuously.

Observe Cattle Behavior

Cattle behavior is the most direct indicator of heat stress. Learn to read the signs. Panting is the first obvious sign. Watch for the severity of panting, not just whether cattle are panting. Open mouth panting with drooling is more severe than closed mouth panting.

Cattle that are heat stressed stand instead of lie down. They bunch together in shade or around water. They reduce activity and may stand with their heads down. They crowd toward any available shade, even if it is inadequate. These behaviors tell you that your facility adjustments are not enough.

Record Daily Observations

Keep a simple daily log during summer. Record the date, time, temperature, humidity, wind speed, and THI. Note cattle behavior, feed intake, water consumption, and any deaths. This record helps you spot trends and evaluate whether facility changes are working.

The log does not need to be elaborate. A notebook or a simple spreadsheet works. The act of recording forces you to observe carefully. Over time, the record shows you which pens have problems and which adjustments provide the most benefit.

Use Technology Where Helpful

Several technology options can assist with heat stress monitoring. Weather stations that report THI in real time are available at reasonable cost. Some feedlots use ear tag sensors that monitor cattle temperature and activity. These are more expensive but can provide early warning of heat stress in individual animals.

Smart waterers can track water consumption per pen. A drop in water intake is an early sign of problems. Feed tracking systems show changes in intake that may indicate heat stress. Use technology where it fits your operation, but do not let it replace direct observation.

Common Facility Mistakes and How to Avoid Them

Even experienced feedlot managers make mistakes with summer facility management. The following are the most common problems and the practical fixes.

Blocking Wind With Heat Management Structures

It is easy to build shade or windbreak structures that inadvertently block summer airflow. A solid shade roof that is too low can trap hot air under it. A windbreak that was built for winter can create a heat trap in summer. Always consider airflow when building or modifying structures.

The fix is to design for both seasons. Use slatted or partially open windbreaks. Build shade high enough for air to move under it. If you have a solid windbreak causing summer heat problems, open it up or remove it during the hot months.

Overwatering With Sprinklers

Sprinklers that run too long or too often create mud and humidity. Wet cattle that do not dry off cannot cool themselves. The result is more heat stress, not less. Overwatering also damages pen surfaces and creates drainage problems.

The fix is to time sprinklers carefully. Use short cycles of 1 to 2 minutes and let cattle dry between cycles. Stop sprinkling early enough that cattle are dry before night. In humid conditions, reduce or stop sprinkling altogether.

Inadequate Water Flow

Many feedlots underestimate how much water heat stressed cattle need. A tank that was adequate in spring can be insufficient in July. Cattle crowd around tanks, dominant animals push others away, and some cattle go without water.

The fix is to measure flow rates and tank space before summer. Add tank space where needed. Check flow rates weekly during summer. Have a plan to add temporary tanks during heat events. Water is the most important facility factor, so give it priority.

Ignoring Pen Drainage

A pen that does not drain well creates mud and humidity at cattle level. The problem is worse in summer because heat and moisture combine to create uncomfortable conditions. Mud also makes cattle harder to handle and increases the risk of injury.

The fix is to maintain pen slope and drainage. Clear drainage ditches before summer. Scrape pens to remove manure buildup. Repair low spots where water pools. A dry pen is a cooler pen.

Forgetting Nighttime Cooling

Cattle need to cool off at night to recover from the day's heat. If facilities trap heat overnight, cattle do not get the recovery they need. This is especially a problem in pens with solid windbreaks, low shade, or poor airflow.

The fix is to design for nighttime cooling. Ensure airflow through pens at night. Do not leave cattle wet overnight. Keep shade structures from trapping heat. A good night of cooling makes cattle more resilient the next day.

Decision Thresholds for Facility Adjustments

Knowing when to make facility adjustments is as important as knowing how to make them. The following thresholds provide a practical framework. Adjust them to your specific conditions and cattle type.

Routine Summer Conditions

When THI is below 75, maintain normal operations. Ensure water tanks are full and flowing. Keep pens scraped and drained. Monitor cattle during the hottest part of the day. This is the time to prepare for hotter conditions, not react to them.

Watch Conditions

When THI reaches 75 to 78, start active monitoring. Check cattle multiple times per day. Verify that all water systems are working. Begin to shift more feeding to the evening. Watch for early signs of heat stress such as increased panting and reduced activity.

Alert Conditions

When THI reaches 79 to 83, implement your heat event plan. Feed 70 percent or more in the evening. Start sprinklers if conditions are dry. Ensure shade is available and accessible. Monitor cattle closely through the afternoon. Consider reducing handling and processing activities.

Emergency Conditions

When THI is 84 or above, take emergency measures. Run sprinklers on a regular cycle. Provide additional water tanks if possible. Consider using fans in high risk pens. Monitor cattle continuously through the afternoon. Stop all nonessential handling. Be prepared to call a veterinarian if cattle show severe signs.

Severe Heat Event Planning

A severe heat event is forecast when THI is expected to reach 88 or above for multiple days. These events require preparation before they arrive. Fill water tanks and check all systems. Have sprinklers tested and ready. Plan for night feeding. Identify high risk pens and prioritize them for cooling measures.

During a severe heat event, do not work cattle unless absolutely necessary. Processing adds stress and increases heat load. If you must handle cattle, do it in the early morning when temperatures are lowest. Have a plan for emergency veterinary care before the event starts.

Monitoring and Recordkeeping Systems

A systematic approach to monitoring and recordkeeping helps you catch problems early and evaluate your facility adjustments. The following system is simple enough for any feedlot to implement.

Daily Summer Log

Create a daily log for the summer months. Record the date, time of observation, temperature, relative humidity, wind speed, and THI. Note cattle behavior in each pen, especially panting and bunching. Record feed delivery times and amounts. Note water consumption if you have meters.

The log does not need to be elaborate. A spiral notebook or a simple spreadsheet works. The key is consistency. Record at the same times each day so you can compare conditions across days.

Pen Specific Records

Keep records for each pen. Note pen conditions such as shade availability, water tank status, and pen surface condition. Record any facility repairs or adjustments. Track cattle in each pen, including any signs of illness or distress.

Pen specific records help you identify which pens are at highest risk. You may find that one pen consistently shows more heat stress than others. That pen may need additional shade, better drainage, or other facility improvements.

Heat Event Documentation

Document each heat event thoroughly. Record the conditions, the actions you took, and the outcomes. Note which facility adjustments worked and which did not. This documentation becomes your playbook for future heat events.

After a heat event, review your records. Did you start sprinklers early enough? Did water flow keep up with demand? Were there bottlenecks in shade access? Use the review to improve your heat event plan for next time.

Evaluating Facility Improvements

Track the performance of facility improvements over time. If you add shade to a pen, compare cattle performance before and after. If you improve drainage, note whether the pen stays drier. These comparisons help you decide where to invest in future improvements.

Remember that facility improvements have benefits beyond heat stress. Shade reduces solar radiation year round. Good drainage improves pen conditions in all seasons. Water system improvements benefit cattle in every weather condition. Consider the full value of improvements when making decisions.

When to Call a Veterinarian or Extension Agent

Most heat stress management is within the capability of a well run feedlot. However, there are times when you should call for professional help. Knowing when to call can save cattle and money.

Call a Veterinarian When

Call a veterinarian if you see cattle with severe heat stress signs that do not respond to your cooling measures. Severe signs include open mouth panting with excessive drooling, staggering, collapse, or cattle that cannot get up. These are emergency conditions that require immediate veterinary attention.

Also call a veterinarian if you see an unusual number of sick cattle during a heat event. Heat stress can trigger other health problems. Cattle that are weakened by heat are more susceptible to respiratory disease and other conditions. A veterinarian can help you distinguish heat stress from illness.

If you have cattle that die during a heat event, call your veterinarian to determine the cause. This is important for both animal health and regulatory reasons. Your veterinarian can help you document the event and take appropriate action.

Call an Extension Agent When

Call your local extension agent when you want to evaluate your facility design or management practices. Extension agents can provide guidance on shade design, water system capacity, sprinkler systems, and pen management. They can also help you develop a heat event plan specific to your operation.

Extension agents are also valuable when you are planning facility improvements. They can help you evaluate the costs and benefits of different options. They may have access to research and case studies from other feedlots that can inform your decisions.

Building Your Support Network

Develop relationships with your veterinarian and extension agent before you need them. Invite them to tour your facility. Share your monitoring records and heat event plans. Ask for their input on improvements. A veterinarian or extension agent who knows your operation can provide much better advice in an emergency.

Keep contact information for your veterinarian and extension agent posted in the office and in the feedlot. During a heat event, minutes matter. You do not want to be searching for a phone number when cattle are in distress.

Regulatory Considerations

Heat stress deaths in feedlot cattle may need to be reported depending on your location and the number of animals involved. Your veterinarian can advise you on reporting requirements. The USDA APHIS Cattle Health division provides guidance on reportable conditions. Your state animal health officials can also provide information.

If you have a large number of deaths, you may need to arrange for proper disposal. Your veterinarian and extension agent can help you understand disposal options and requirements. Do not wait until an emergency to understand these requirements.

Frequently Asked Questions

How much shade do feedlot cattle need in summer?

Provide at least 20 to 40 square feet of shade per animal. A practical rule is 2 to 3 inches of linear shade per animal along the shade structure. During extreme heat events, more shade is better. Prioritize shade for heavy cattle, black cattle, and newly arrived cattle if you cannot shade all pens.

What is the best way to cool feedlot cattle in extreme heat?

Water is the most important factor. Ensure adequate tank space and flow rate. Then use shade to reduce solar radiation. Sprinklers can help in dry conditions but must be timed so cattle dry off before night. Air movement through the pen is also critical. Combine all of these measures for the best results.

Should I feed cattle more in the morning or evening during summer?

Feed 70 percent or more of the daily ration in the evening. Cattle naturally eat more in cooler evening hours. Evening feeding also means cattle generate digestive heat during cooler periods. Support this with well lit feed alleys and crews available for night feeding.

How do I know if my water tanks are adequate for summer?

Measure linear tank space and flow rate. You need 2 to 3 inches of linear tank space per animal. Each tank should refill at 10 to 15 gallons per minute. During heat events, cattle can drink 25 to 30 gallons per day. If tanks empty during the day, you need more capacity or faster flow.

When should I use sprinklers on feedlot cattle?

Use sprinklers when THI is above 79 and humidity is low. Run short cycles of 1 to 2 minutes every 30 to 60 minutes during the hottest part of the day. Stop sprinkling 2 to 3 hours before sunset so cattle are dry overnight. In humid conditions, sprinklers are less effective and may do more harm than good.

Can windbreaks cause heat stress in summer?

Yes. Solid windbreaks that block summer breezes trap heat in the pen. If you have permanent windbreaks, consider making them partially open or removable. In summer, the priority is airflow, not wind protection. Open up pens to prevailing summer winds.

What is the temperature humidity index and how do I use it?

The temperature humidity index combines temperature and humidity into a single number that predicts heat stress risk. A THI below 75 is safe. At 75 to 78, watch cattle closely. At 79 to 83, implement your heat event plan. Above 84, take emergency measures. Calculate THI from a chart or online calculator using your local temperature and humidity.

How do I know if my facility adjustments are working?

Monitor cattle behavior and performance. Cattle that are comfortable eat well, lie down to rest, and do not pant excessively. Track feed intake, water consumption, and daily gains. Keep records of heat events and compare outcomes. If cattle show less heat stress and maintain performance, your adjustments are working.

Related Farming Guides

This section will be populated with links to related farming guides on cattle management, feedlot operations, and seasonal livestock care. Check back for additional resources on beef cattle production and facility management.

Related Clinical & Scientific Guides

• Cattle Head Gate Selection and Adjustment
• Beef Cattle Handling Facility Flow
• Beef Cattle Maternity Pen Design: Comfort and Monitoring

References

• Beef Cattle Research Council: https://www.beefresearch.ca/
• USDA APHIS Cattle Health: https://www.aphis.usda.gov/livestock-poultry-disease/cattle
• WOAH Terrestrial Animal Health Code: https://www.woah.org/en/what-we-do/standards/codes-and-manuals/terrestrial-code-online-access/
• FAO Animal Production and Health: https://www.fao.org/animal-production/en/
• WOAH (World Organisation for Animal Health): https://www.woah.org/en/home/

This article is educational and is not a substitute for veterinary diagnosis, treatment, public-health guidance, or regulatory reporting.