Heat stress…How cattle are made more comfortable

The heat and humidity of summer are arriving in many parts of Nebraska, as well as the rest of the country. Today I will share with you some of things beef farmers and ranchers do to help make their cattle as comfortable as possible during these weather events.

Heat stress is hard on cattle and other livestock (and people!), especially when combined with high humidity and low wind speeds. Heat stress can reduce an animal’s feed intake, weight gain, reproductive efficiency, and milk production, while increasing their susceptibility to diseases (due to increased stress on their overall body system).

Signs of heat stress can include animals bunching, seeking shade, panting, slobbering or excessive salivation, foaming around the mouth, open mouth breathing, and/or lack of coordination and trembling.

Cattle heavily panting and salivating during a heat event. Photo source: Dr. Terry Mader.

If beef farmers and ranchers see such symptoms they will assume the animal is suffering from too much heat and immediately try to minimize the stress to the animal, especially by reducing handling or movement of the animal. Additionally, the previous health of individual animals is an important risk factor, as animals with past health problems will be more affected by heat stress than animals with no prior health problems. These animals will generally be the first to exhibit signs of heat stress and be the most severely affected.

The heat index commonly reported by media outlets is a good place to start in understanding animal heat stress.

Beef farmers and ranchers can use a tool like this to look at temperature and humidity levels to find the heat index – letting them determine a course of action.

If the heat index is above 100 degrees, animals can tolerate it if shade is available and/or wind speed is at least 10 miles per hour. Shade can be provided by trees, buildings or other sunshades. If providing shade is not an option, you may see beef farmers or ranchers move cattle to outside or parameter pens where the airflow is the greatest or to a higher spot where there may be more airflow. If animals are inside a building that is not climate controlled, it is important that airflow through the building is created (opening windows, having fans, open sides,etc). In addition, the temperature can be lowered by spraying cool water on the roof and walls of buildings where the animals are being housed.

If the index gets above 110 degrees, animals will be stressed regardless of wind speed. If possible, market ready animals should have access to shade and airflow. ALL animals should have plenty of access to cool, clean water. Sometimes you may see beef animals standing in water in an attempt to cool down. This can help them stay comfortable, but it can also be risky if they get down in the water and cannot get up. If a heat index above 110 is predicted, livestock that need to be moved or transported should be out of the facilities by early morning but certainly by noon, if possible.

If the heat index is above 115 degrees, market ready animals should not be moved or handled at all!

If the heat index is above 120 degrees, no activity should occur for animals or humans!

During the heat of summer, beef farmers and ranchers may provide: shade (not always an option), ventilation and air flow, plenty of clean and cool water, skin wetting (if possible) with sprinklers and hoses, and cool water drench (if the animal becomes very distressed – a veterinarian may have to assist with this procedure). If used, sunshades would be high enough off the ground (10 feet or more) to allow for adequate air movement.

If animals are wetted down, the droplet size needs to be large enough to wet their skin, not just the hair. A small droplet size will usually just wet the hair creating more humidity for the animal, thus not helping at all.

During these high heat, high humidity events the best time of day to work beef animals is in the very early morning hours when it is still relatively cool. Beef animals will be hot during the day, and will need several hours in the cooler evening temperatures to get their body temperature to a level that is not distressful.

Beef farmers and ranchers do their best to make sure their animals are as comfortable as possible during these high heat, high humidity weather conditions. The best scenario is a nice breeze and cool evenings!

Cows under tree
Cattle seeking shade under trees.

For more information on heat stress check out Feedlot Heat Stress Information and Management Guide, Heat Stress – What You Should Know to Make Livestock Shows a Success, or How to Reduce Heat Stress in Dairy Cattle.


Dr. Lindsay can also be found on:

– Twitter/Instagram (agwithdrlindsay)
– Facebook (https://www.facebook.com/agwithdrlindsay)
– Pinterest (Lindsay Chichester-Medahunsi)

Why is there a hole in that steer? … Fistulated Fun Fact Friday

At UNL we have several fistulated steers which are used for research and education. Traditionally, these fistulas (also called a cannula) were inserted for research purposes. The fistula can either be on their neck (esophageal fistula) to monitor what they eat, especially when grazing to determine grazing and forage preferences OR it can be on their left side, which goes into the rumen, the largest compartment of their stomach to monitor feed and diets, ultimately making livestock rations more efficient. I talk more about ruminants (livestock with one stomach which has four compartments) here.

But today I want to introduce you to the UNL Mobile Beef Lab!

The Mobile Beef Lab, if you see us on the road be sure and wave – we are a friendly bunch!

There are actually two of these labs in Nebraska, with the intent to educate! Each lab has one steer and a team of Educators. The Educators all have livestock backgrounds, so they know their way around an animal and a trailer. Additionally, everyone on the teaching team has been IACUC (Institutional Animal Care and Use Committee) certified. Every University that does research or education with animals will have an IACUC Office and people who regulate all use of these animals. The primary purpose is to ensure that the animals are well cared for; are not in pain or danger; and are being provided the best possible care at all times. To learn more about IACUC at UNL check out this page.

These labs go to schools, fairs, festivals, and other community events. When we take the lab out we talk about microbiology, ruminant nutrition, food production, forage resource management, anatomy and physiology, animal care, and more! And the best part…you can put your arm through the hole to reinforce what you learned!

Heather helping a student understand what he is feeling inside the rumen.

At schools we can set up microscopes. Students have a chance to remove a small portion of the rumen fluid and look at it under a microscope to see all of the microorganisms and their activity!

The microscope can be set up in the trailer for close convenience…
…or it can be set up in a classroom as Steve is assisting with here.

The Mobile Beef Lab is an excellent way to start conversations. We have been to some great places with it, such as –

Husker Harvest Days near Grand Island, Nebraska.
The Nebraska State Fair in Grand Island, NE.
And Werner Park for a baseball game near Omaha, NE.

So now you probably have some questions, we get asked several of the same ones repeatedly, so I will do my best to answer what you may be thinking…

Does it hurt? No, once healed it is like having an earring or a gauge in your ear. The steer doesn’t know it is there and he lives a completely normal life. He sleeps, runs, and eats just any other beef animal would. Fun fact: there are no nerve endings in their stomach, so they can’t feel our arms and hands in their rumen!

The steer eating from the bunk and hanging out with the State Fair Breeding Pavilion Heifers. He is very happy and healthy as you can see!

How was that (aka the fistula) put in? When the steer was about 500 pounds he underwent a procedure at UNL with veterinarians and veterinary students. Our teaching team was present and viewed the procedure (I didn’t think to get pictures when it happened a couple of years ago). They numbed the entire area with a local anesthetic (similar to what they would do to you at the dentist for a procedure) so he couldn’t feel anything. A small circle of the hide was removed, the muscle tissue was teased apart to get to the lining of the stomach. A small slit was cut in the lining of the stomach, and then the hide and stomach lining were stitched together. The fistula was inserted, and is a soft, pliable plastic devise that most similarly resembles a spool that thread comes on. It is larger on the inside of the stomach and the outside of the body to hold it in place. Then a plug is inserted into the middle, which comes out and goes in (it very rarely ever falls out on its own, we have to always manually removed it and put it back in) to seal up the fistula when the steer is not being used. The steer’s pain was monitored until it was completely healed.

An example of what the fistula looks like.

But I am scared to put my arm in there… There is nothing to be scared of. Our teaching team is by your side the entire time, our steer is very mellow and does this a lot. Additionally, there is nothing in there that can hurt you. It is like putting your hand into a warm bowl of soup, that is churning 🙂

How long will you keep the steer? We will keep him for years if we can. By having this procedure done the steer has become more valuable. He is also very tame, and he gets to meet lots of new people every year. As long as he stays healthy and maintains a good temperament we will keep him. We never want to put him or anyone who meets him in danger or harm.

What happens when he is harvested? When he is harvested (slaughtered) for meat, it will be like any other beef animal. The fistula will be removed and the persons who harvest him will have to be very careful that none of the rumen content gets on the carcass, so as to maintain a safe food source. He will be harvested and processed just like any other meat production animal.

What other questions do you have?


Dr. Lindsay can also be found on:

– Website (http://food.unl.edu/ag-and-food)
– Twitter/Instagram (agwithdrlindsay)
– Facebook (https://www.facebook.com/agwithdrlindsay)
– Pinterest (Lindsay Chichester-Medahunsi)