Heat stress can create challenges for cattle as their thermal neutral zone is less than humans. Cattle are comfortable with cool temperatures, and more affected by the heat. More research is being done about heat stress in cattle during the feeding and growing periods.
During the summers of 2021 and 2022, two growing heifer studies were conducted at Kansas State University to evaluate impacts of limit feeding a high-energy ration at 2.2% of body weight daily on a dry matter basis in combination with shade.
The results showed cattle with shade performed better.
An increase in animal comfort was attributed to reduced solar radiation exposure in shaded pens, leading to lower heat load during the summer.
When shade is provided during times of heat stress, the results of the study showed:
- improved average daily gain by 7%
- increased feed intake by 6%
- improved feed efficiency by 4%
- improved cattle comfort (measured by panting scores)
- reduced water usage (consumption) by 11%
Further studies on mitigating heat stress
Madeline Mancke, a doctoral student at K-State, recently shared on the BCI Cattle Chat podcast about her research that was sparked by producer questions relative to effective heat mitigation, specifically in fed cattle and feedyard scenarios.
The study included a randomized control trial at a feedyard in the Pacific Northwest with roller compacted concrete pen.
“They were interested in the effect of shade on steer performance after terminal sorts,” Mancke says. “We allocated about 8,000 head of animals into that trial, with 12 pens under shade and 12 pens with no shade. Each animal had about 30 square feet of 100% solar block.
The trial evaluated several different measurements including performance, behavior, and animal welfare components. Researchers were able to follow the cattle all the way through the packing plant.
“We found we had better carcass performance coming out of shaded pens,” Mancke says. “Higher quality grades Prime and Choice came out of shaded pens and less dark cutters. We also found a decrease in the amount of railers or animals that got culled earlier than their pen mates.”
In addition, Mancke notes decreased panting behavior and a decrease in water consumption.
“We found about a 15% decrease in water consumption with the inclusion of a shaded pen,” she says. “As far as feed delivery goes, we saw no differences in the shaded pens when it started getting hot out and when you think of cattle going off feed in the heat. In the unshaded pens, we saw a decrease [in consumption] when that temperature humidity index increased, however, we did not see the shaded pens going off feed with that increasing temperature.”
Clinical sciences professor Bob Larson says a 15% decrease in water consumption is meaningful.
“If you think about the number of head in a large feedlot, 15% reduction of water on a daily basis is significant,” he says. “Water is one of the resources that we’re really trying to kind of keep an eye on as we think about livestock production.”
The study took place after the terminal sort, which is about 60 days from the projected ship date.
Mancke is working on additional studies this coming summer to mitigate heat stress by adjusting feeding times.
“Rather than conventionally fed cattle, where we think of them getting fed between 5 a.m. and 3 p.m. two to three times a day, we’re going to start feeding them after that,” she says. “That environmental max temperature is done for the day, so we’re going to try to offset that heat load and let them be able to eat throughout the night and not during that peak temperature during the day.”
Read more: “Shade Trees” Keeping Cattle Cool in Nebraska Feedyard
