Rising Temperatures Threaten Nebraska's $14 Billion Cattle Industry
Scientists seek to develop new uses for heat-trapping methane gas
By: Nora Lucas
Cattle, like people, don’t do well in hot, humid weather. Unlike humans, they don’t have the option to retreat to air-conditioning for relief. Disorientated and agitated, overheated bovines stumble around with frothy mouths agape before collapsing.
The bad news for Nebraska ranchers (and cattle, of course) is the number of hot days that can trigger these responses are occurring more frequently — a growing risk from climate change to an industry that contributes $13.8 billion to the Nebraska economy.
Terry Mader, Ph.D., a retired University of Nebraska–Lincoln animal science professor, said two significant heat events led to significant cattle losses in all of the 1980s. In the 1990s, there were four. Now, at least one extreme heat event occurs every other year.
“If a livestock operation is to be sustainable, they must be prepared for adverse weather events, which could affect the health and welfare of the animals in the operation,” Mader said.
The story of climate change and cattle is a story of cause and effect. So far, it’s been mostly cause.
While fossil fuels account for the vast majority of greenhouse gas emissions, agriculture contributes a-not-insignificant slice of the pie — about 10 percent of the emissions in the US. And livestock production through the release of methane, a potent greenhouse gas, is the biggest contributor within agriculture.
But there are effects, too.
A hotter cow is also a thirstier and weaker cow — and one that is less productive, i.e. generates less revenue. Extreme weather events, like last year’s bomb cyclone, mean more animal losses and new expenses for repairing damaged property, threatening ranchers who already operate on the margins.
As the rain fell in sheets last spring, UNL student and animal science major Felicia Knoerzer said it was impossible to keep pens bedded with straw and calves free of mud.
“We did everything in our power to ensure the safety and well-being of our animals,” she said. “However, Mother Nature was not on our side.”
The family operation lost more calves than it ever had, Knoerzer said.
“Farmers are on the front ends of climate,” says Graham Christensen, who promotes environmentally-friendly agriculture practices through his consultancy GC Resolve.
Over the past century, Nebraska’s temperature has increased by 1 degree Fahrenheit. Models suggest that Nebraska’s temperatures could increase by another 4 to 9 degrees by 2075.
The 2014 climate study projected that the number of nights above the 80-degree mark could increase by 40 nights by 2075.
Cattle, which spend most of their lives outdoors, are resilient animals. Beef cattle can tolerate a wide range of temperatures. But they are most comfortable, and therefore most productive, between a range of 60 and 80 degrees.
“Animal productivity is optimized within narrow environmental conditions,” UNL’s Mader wrote in a 2014 UNL climate study. “The impacts of climate change and rising CO2 are certain to affect all major food-producing domestic livestock species.”
Without the ability to cool down at night, cattle undergo heat stress, a biological response that can limit a cattle’s ability to gain weight. They are more susceptible to disease, require more water and eat much less, translating to loss of revenue for ranchers.
Beef and dairy cattle that spend most of their lives outdoors will be “particularly vulnerable,” Mader wrote.
“Climate variability has already had an effect on livestock production in recent years,” he wrote in an email.
Adding shady spots, more water holes and less fatty feed can mitigate the effects of heat stress on cattle. But the United States Department of Agriculture reported that these methods increase costs to production and capital.
With rising temperatures and humidity, climate change also brings greater variation in the amount of rainfall. In worst-case scenarios, cattle could drown in overflowing rivers, or, as was the case last year, be buried by blizzards.
Last year’s flooding cost Nebraska $400 million in livestock losses. John Hansen, president of the Nebraska Farmers Union, said severe weather damaged fences, led to soil loss and destroyed roads and bridges, adding new stresses for farmers and ranchers who “were already barely hanging on.”
The variation in weather, more pronounced in a warming world, can be difficult to manage, according to Travis Mulliniks, Ph.D., a range cattle nutritionist at UNL.
“Rising temperatures means that winter is very different, which leads to performance quality changes,” he said. “Last winter, it was wet, it was extremely cold. This winter has been really open for us. Those yearly variations in temperature change the management strategy.”
Changing management means more time and labor, in addition to higher costs, to adapt to unforeseen weather.
Cattle are ruminant animals, meaning they have multiple stomachs, whereas a pig or a chicken only has one. An advantage of these ruminant animals is that they can consume products that humans cannot — leading to less food waste and higher productivity.
Cattle, however, contribute to greenhouse gas emissions.
Cattle produce methane in the digestive process, most of which is expelled in burps. That’s bad for the planet because methane is a more potent greenhouse gas than carbon dioxide, though it dissipates in the atmosphere decades sooner.
Agriculture scientists are looking for ways to reduce the amount of methane cattle produce, which could pay off economically for livestock producers, said UNL livestock engineering professor Rick Koelsch, Ph.D.
“Anything not lost as methane is potentially energy that could be used for the growth of the animal,” he said. “Methane is a loss we’ve just historically accepted, and now we’re looking at how to utilize that energy.”
Koelsch, who serves on the U.S. Roundtable For Sustainable Beef, a group that includes academics, agribusiness leaders, environmentalists and food service executives, said that to reduce emissions, cows must get to weight more quickly so fewer feed and water resources are consumed. This means lower cost for the producer and lower environmental impact.
“If we spend more days trying to raise that animal to a certain desired weight, then we have more manure produced, more greenhouse gases, we have a larger environmental footprint,” Koelsch said.
The primary concern from farmers right now, according to Hansen, is the prospect of rising commodity prices, which barely cover the cost of production. With lower yield of feed due to climate change, this will only continue.
“Our nation desperately needs more, not fewer, family farmers and rancher resource managers who have a deeply felt conservation ethic and want to do everything in their power to leave the land in a better condition than they found it for future generations,” Hansen said.
Knoerzer takes this to heart. She said that while climate change presents new challenges, her family has years of experience that so far has allowed them to handle whatever situation they face.
“Do we want to raise cattle in conditions like last spring? Absolutely not. But we will do everything we can to ensure those animals receive the best treatment regardless of the conditions we are faced with,” Knoerzer said.