Summer heat has returned to most of Iowa this weekend and into the coming week. High temperatures are expected to approach 90 degrees F. Even though that’s cooler than the stretch of hot days the state saw in July, livestock producers should still prepare.
Each species of livestock reacts to heat differently. However, the common principle is to maintain good ventilation, offer shade, provide clean and cool water, and limit moving animals during the hottest hours of the day.
Swine care. Pigs do not have sweat glands, making them especially susceptible to heat stress, according to Jason Ross, director of the Iowa Pork Industry Center at Iowa State University. Swine producers commonly rely on cooling fans and evaporative cooling systems that help the animal to increase evaporative heat loss and stay cool. Keeping the system running at optimal levels is critical during periods of extreme heat.
Ross suggests producers make sure all controllers and fans are functioning properly, including any misters or cooling cells, and be sure the backup generators are ready to operate in the event of a power outage.
Beef cattle. Compared to swine, cattle can tolerate higher temperature at lower relative humidity because cattle can dissipate their body heat more effectively by sweating. However, cattle are more prone to stress when the humidity rises and need the same level of care as other livestock.
ISU Extension published an article in June about how beef cattle farmers should prepare. Common solutions for cattle include access to clean, cool water; shade; and good ventilation. Avoid moving cattle during daytime and afternoon, when temperatures are at the highest, because the energy cattle expend while moving will cause even more stress.
This may be a good time to install some additional fans or water misting systems, or to make sure the systems you have are fully functioning.
Evaluate your cattle in the morning and again in afternoon to make sure they are coping with the heat. Pay close attention, as the rapid change in temperature may catch some at-risk cattle (cattle at end of feeding period or cattle with previous respiratory disease) dealing with excessive heat stress.
Dairy cattle. Access to cool, clean water is vital for dairy cows during periods of high heat. A dairy cow consumes up to 50% of her daily water intake within an hour after milking, so providing fresh, clean water at the parlor exit is an excellent way to encourage water consumption.
Fans and sprinkler systems are commonly used on dairy farms but must be properly installed and functional to provide the necessary air and water movement. The idea is to soak the cow to her skin and turn the water off for a long enough period to allow the moving air to dry her. While drying, heat is removed from the skin during the evaporation process, cooling the cow. When people climb out of a swimming pool and experience a chill until their skin dries, they are experiencing the same process.
Poultry. Like swine, poultry do not have sweat glands and therefore cannot rid their body of heat by sweating. Birds are subject to heat stress when humidity and air temperature rise uncontrollably. They often respond by panting, which may help, but also expends energy and requires the bird to consume more water, to account for moisture lost through panting.
High humidity decreases poultry heat loss from the lungs, which makes the birds more prone to heat stress. For older turkeys, temperatures at 85 degrees with humidity above 50% is considered the danger zone. At 90 degrees and 50% humidity, the risk increases to extreme.
Airflow and ventilation are key to managing poultry during hot weather. Producers also may want to feed at night, or after temperatures begin to fall.
Feed and water supplements may also be necessary. According to University of Minnesota Extension, electrolytes can be added to a flock’s drinking water for up to three days. Potassium chloride electrolytes appear to increase water intake when provided in drinking water at 0.6% concentration. You should start providing electrolytes prior to the heat stress period.
Sodium bicarbonate in the feed, or use of carbonated water, is especially helpful for hens in egg production. Panting and carbon dioxide release can change the acid-base balance in poultry, and also can change the bicarbonate available for egg shell formation. Providing sodium bicarbonate can help lessen these changes.