The first week of August brought a short reprieve to many of us struggling with hot and dry conditions, but many others are still experiencing record-high temperatures and a late start to fire season. Some of you have likely been managing extreme weather for decades, while for others new to ranching or who live in a place where heat has not been a problem in the past, it may be your first time experiencing this added stress on livestock. We spoke with Ashley Wright, Livestock Area Assistance Agent at the University of Arizona, and Skyler Bentley, Animal Care Manager at the campus farm for the College of Veterinary Medicine at the University of Arizona, who offered some tips and advice on how to keep livestock safe during bouts of extreme heat. 
 

The risk of heat stress isn’t solely based on the dry bulb, it's also affected by the relative humidity (higher humidity makes evaporative cooling much more difficult), solar radiation (sun vs shade), air movement (is it breezy or calm), and precipitation. I recommend using the temperature humidity index when assessing if it's too hot to work animals, as it’s a better indicator of the possibility of heat stress. Heat stress when working animals can be avoided by monitoring the temperatures. There are several charts available online for each individual species to use as guidelines for when the temperature humidity index (THI) is in the danger zone. Remember when using these charts they are meant as a guide only, animals who are adapted to cooler temperatures may be susceptible to heat stress at lower temperatures than animals acclimated to hot climates. If you must work animals on hot/humid days, work them in the morning when temperatures are coolest and work them slowly to minimize stress and exertion. Monitor them for signs of heat stress, and consider making some changes to your facilities to help animals (and people) stay cool.

Animals experiencing heat stress exhibit a number of signs of distress. By being aware of these signs, you can adjust your housing or schedule for working animals to mitigate or avoid heat stress. Some species are able to sweat very effectively (like horses). Sweating is generally an effective method of cooling, and doesn’t necessarily mean that an animal is overheating unless accompanied by other signs, however be aware that other species such as hogs and chickens have almost no sweat glands and are unable to take advantage of this cooling mechanism. The next sign of heat stress is panting/increased respiration rate, increased water intake, reduced appetite, becoming lethargic, and salivating/foaming at the mouth. If steps are not taken to cool these animals, they will become unconscious and death may occur. If you see animals in signs of distress, take steps to cool them by moving them to the shade, using evaporative cooling (misters or hosing the animal down with cool water), and stop working the animals until temperatures have cooled. 

 

Know the signs of heat stress in your animal species, and if your livestock will let you handle them safely and routinely, know how to check for dehydration. Many animals tolerate heat just fine with their natural mechanisms and may not need a lot of intervention, while others may be surprisingly vulnerable. One of the most reliable ways to check for dehydration is a skin tent. With your fingers, pinch the skin on the animal—If it springs back right away, you’re in good shape, and if it lingers, that’s a sign of dehydration. Because older animals have less skin elasticity, try this trick but use the skin above the eyelid.

 

When thinking about animal housing and working facilities in hot climates, consider the mechanisms of how animals cool themselves and provide opportunities for that to happen more efficiently.

The most basic requirement is shade, to allow animals to move out of solar radiation. Shade structures in pens and working/holding facilities benefit both animals and people and are recommended in warm to hot climates.

Consider convection. Ensure animal barns, buildings, and other structures (especially small, enclosed structures like chicken coops) have adequate ventilation. Utilize natural airflow when possible to vent heat up and out the top while bringing in fresh cooler air through the sides, and add fans if necessary to facilitate air movement. If further cooling is still needed, climates that are not excessively humid can add evaporative cooling to their arsenal. Mister systems (especially when combined with fans) can help keep livestock comfortable on very hot days; just be sure to use the correct number and positioning to prevent moisture buildup in housing environments. 

 

Make sure to offer animals both shade and CLEAN water. Even a small amount of algae will cause colic because the taste is off. Most ag supply stores have water-cleaning additives; consider cleaning regularly. 

 

Make sure salt and minerals are available to livestock. They’re sweating out all this good stuff and will need to replace it. Plus, salt intake kicks on the water intake switch. 

 

Wet down stalls and enclosures for some natural evaporative cooling.

If you use misters, be sure not to use them on wool sheep, as wet wool doesn’t allow air to circulate and cool the body. If you use misters on other species, check periodically that it isn’t making the air more humid and exacerbating the problem. (If sheep are in heat stress situations, a tip I learned is to use alcohol on the non-woolly parts of their body (armpits, inguinal area, etc., for rapid evaporation and cooling). 

 

If you like to give your animals baths to cool them down, take caution not to use soaps/shampoos too often. They break down the natural protective oils on the skin and hair, leaving them more vulnerable to sunburn. 

 

You can use sunscreen (we use baby sunscreen) on horses and other friendlier animals at risk of being burned (think light-colored, pink noses, thin hair, etc). 

 

Frozen treats make everyone happy! We like to put ours in big bundt cake molds so we can hang them around the enclosure. There are lots of awesome variations on this. 

 

Control flies. Herd animals bunch together when flies are bad, upping body heat. 
 

Horses: Horses are probably the least at risk for heat stress due to their ability to sweat extremely effectively; the biggest risk is when working hard on very hot/humid days. For housing, ensuring shade, fresh water, and adequate ventilation is typically enough to keep them comfortable on even the hottest days. When working horses, monitor their sweating and respiration rates and consider providing extra electrolytes/salt to offset losses due to sweating. If days are extremely hot, keep working sessions short or move them to early morning or a covered/shaded arena if possible.

Cattle: Cattle are somewhat susceptible to heat stress, especially when overcrowded or being worked. Work them at cooler times of the day, and try to work them slowly while minimizing stress. Avoid overcrowding holding pens.

Sheep/Goats: Similar to cattle. Shear sheep before the onset of warm temperatures and provide plenty of shade to prevent sunburn in freshly shorn animals.

Pigs: Pigs are very susceptible to heat stress. Avoid working or stressing pigs during hot times of the day. Pink pigs are also very prone to sunburn and should be kept in the shade as much as possible. Provide adequate water and a place to wallow in cool water/mud to allow them to cool themselves or house them in buildings with climate control mechanisms in place.

Poultry: Birds are also quite susceptible to heat stroke. If not in a climate-controlled building, ensure coops are well-ventilated, and run has plenty of shade. Avoid overcrowding, and utilize misters and fans whenever possible to further cool the environment. Birds will increase water intake as a mechanism for cooling themselves, so make sure plenty of clean water is available.

Dogs: Don’t forget about yourself and your working dogs. Dogs are very susceptible to heat stroke. Like pigs, they lack a meaningful number of sweat glands and rely on increased respiration (panting) to cool themselves. Monitor working dogs for signs of heat stress, and make sure they have access to water for drinking and swimming to help them stay cool. Use working dogs very cautiously or not at all on very hot days.

Humans: People who are working hard can also fall prone to heat exhaustion. We sweat quite well, but be sure to consume adequate electrolytes to replace those lost during sweating, along with plenty of water. All the other recommendations that benefit animals also benefit people: shade, moving air, and evaporative cooling when necessary. Wear light-colored, loose-fitting, breathable clothing, hats, and sunscreen.

 

Ashley Wright is a livestock area agent providing leadership for extension programs in livestock production and management at both the large and small scale levels. She serves producers in Cochise, Pima, and Santa Cruz Counties. Topics of interest include herd health and welfare, nutrition, reproduction, marketing, breeding and genetics, meat quality assurance, niche marketing, and rangeland health, with the overall goal of improved profitability and long-term sustainability.

Skyler Bentley has been the Animal Care Manager for the large and food animal species at the University of Arizona's College of Veterinary Medicine since the program began in 2020. She has overseen the care of horses, cattle, sheep, goats, donkeys, and poultry in Arizona and California.

With mixed emotions, we are celebrating one of our board members, Cheryl Peterson, who is increasing her role at McIntosh Seed and stepping away from the WIR board to fully commit to her increased responsibilities in her local community. Cheryl and her colleagues have worked long and hard for Black and Brown families, landowners, and communities to access funding and other resources from which they’ve been excluded for many generations. We look forward to staying in touch and watching her work blossom and grow. In the meantime, Cheryl has recommended a fantastic replacement, and we’ll be moving through the nomination process one last time in 2023. Here’s to hopeful new beginnings and riding the waves of change.