Featured photo above: A young black Angus calf stares into the camera at Riverview, Florida, 2014. (Photo courtesy Jennifer Campbell)
By Lianne D'Arcy, Education & Communications Intern / UF Thompson Earth Systems Institute
Florida is hot. It’s no secret. The chokehold of Florida’s heat is a permanent part of our landscape, worming its way into every corner of the state, and forcing all living things into a clear-cut choice: adapt or die. And blanketed by the same soupy heat, Florida cattle are no exception.
This issue is not new. Geneticists, cattle ranchers and livestock producers have all been working to keep cows cool in Florida for decades. But average temperatures in the state have been rising. The Florida peninsula has already warmed more than one degree Fahrenheit during the last century, and projections estimate an additional two degree rise in the next 20 years.
As global temperatures remain on the rise, and heat events become more extreme, it’s becoming increasingly important to safeguard the wellbeing of our livestock.
Heating Up
In the face of a warming world, a small, slow rise in local temperatures by a degree or two won’t directly impact Florida’s cattle. The livestock would ultimately continue to mill about pastures and make producers proud.
Issues begin when extreme heat events come on suddenly and persistently, a problem exacerbated by climate change.
So far, 2020 has ranked as one of the hottest years on record. This fact is even more concerning due to the fact that the year has lacked any major El Niño events — an atmospheric phase that contributes to most record-warm years.
And in the future, Florida is projected to experience longer periods of stagnant summer air. They state is also thought to feel even steamier, muggier summers as the dew point temperature — a measure of atmospheric moisture — rises, and see more “danger days,” where temperatures feel as if they’re over 105 degrees Fahrenheit.
A study published last year in the journal Environmental Research Communications predicts that by 2050, Florida will see, "105 days with a heat index over 100 degrees Fahrenheit (up from just 25 days historically) and 63 days with a heat index over 105 degrees Fahrenheit." This means Florida will face some of the highest occurrences of extreme heat in the entire United States.
At heart, the problem is not just an increase in average temperature. As the Earth’s climate changes, Florida also is sure to see a rise in the amount of these extreme heat events, where temperatures are unusually high for a particular time and place. This heat, coupled with Florida’s humidity, serves as a serious danger to both humans and livestock.
Raluca Mateescu, associate professor of quantitative genetics and genomics at the University of Florida, says she likes to tell cattle producers that even if they don’t believe in climate change, and even if they don’t suffer from it, their animals will.
“Ultimately, we need to find a way for our animals to better fare in Florida,” Mateescu said. “We cannot wait until it gets hotter. We need to start now, or else they won’t be able to keep up.”
Introducing Cattle to Florida
Even though heat has dominated Florida’s landscapes for thousands of years, cattle haven’t always been here. Spanish explorer Juan Ponce de León introduced them to the state in the 1521. Since then, cattle have grown to be an integral fixture of Florida’s history and heritage. By the 1600s, over 20,000 cattle grazed 34 ranches in Florida. Today, Florida ranks 13th in overall cattle numbers nationwide, with 15,000 beef producers in the state and over 886,000 cattle. In fact, half of Florida's agricultural land is involved in cattle production, and the industry is estimated to generate nearly $1 billion annually in cattle and product sales from the beef and dairy industries.
Not only is cattle ranching a prominent part of the state’s economy and food security, but these ranches are thought to be the key in preserving the state’s natural spaces. Most ranchlands serve as wildlife corridors and natural spaces for many of the state’s endangered species, such as the Florida grasshopper sparrow or the famous Florida panther. According to the Florida Department of Agriculture and Consumer Services, these natural, low-intensity ‘green spaces’ also filter and recharge underground water supplies, as these pastures mimic the native landscape’s ecological functions.
However, it must also be noted that the cattle industry itself produces carbon emissions that contribute to climate change. The Food and Agriculture Organization of the United Nation states that greenhouse gas emissions from livestock account for 14.5% of all emissions produced by human activity.
Florida’s cattle ranching industry wasn’t always as lucrative as it is today. Smaller, slower, and less productive, the original cattle brought to Florida by the Spaniards merely survived in the Florida heat. It wasn’t until the introduction of the more heat-resistant Brahman breed of cattle that the industry took a turn.
Although the Brahman breed fares well in the heat, it isn’t usually a consumer’s first choice. In the eyes of producers, the Brahman’s tropical adaptation alone cannot outshine its slower growth rate and less-marbled meat. This is why producers began to cross-breed livestock to create a cow that can stand up to both the rising demands of consumers and rising temperatures of the state.
Heat Stress in Florida Cows
Just like us, all cattle will begin to show signs of heat stress when extreme temperatures take hold of the state. They’ll swish their tails, flick their ears and oftentimes wade into the welcoming shade of nearby trees in an attempt to keep cool. Much more sensitive to temperatures than beef cattle, dairy cows have even been known to stand in ponds as a way to beat the heat.
Taylor Davis, the UF/IFAS Livestock and Natural Resources extension agent for Highlands County, described how these steadily rising temperatures impact livestock and cattle farms throughout the state.
“When you have a black cow standing all day in the heat and humidity of a Florida summer, the stress on the cow will begin to show,” Davis said. “And not only will this negatively impact the health of the cow, but it could cost producers millions each year from increased water consumption, breeding deficiencies and deteriorations in the body. Rising temperatures will only further this issue.”
Dairy cattle can experience heat stress at just above 75 degrees Fahrenheit, exhibiting symptoms of stress long before we would. Beef cattle, a bit more resilient, don’t experience heat stress as easily.
Todd Thrift, associate professor and extension beef specialist in the UF/IFAS Department of Animal Sciences, detailed the delicate balance of temperature needed in beef cattle.
“The normal rectal temperature for a beef cow is 101.5 degrees Fahrenheit,” Thrift said. “104 is heat stress, and 108 is dead. There’s a small range to it, much like humans.”
When cattle begin to exhibit signs of heat stress, they’ll become less active. They’ll eat less, sweat more and ultimately become less productive — where dairy cattle will produce less milk, and beef cattle will put on less weight. More time spent and energy is spent trying to cool off, and with their metabolic functions impaired, they become more susceptible to disease.
Vulnerable and hot, cows then turn to ponds and shade. And if a farm or range has an ill-maintained cooling pond, it could harbor infectious diseases such as Leptospirosis. In extreme cases, heat stress can even lead to death.
Beating the Heat
This is where geneticists, ranchers and producers come together. Now filling Florida beef pastures are crossbred cows, specifically engineered to the heat. A common example of this is the Brangus cow: a mix of the heat-resistant Brahman breed and the tender, high-meat-quality Angus breed.
For dairy cows, shade, increased air movement and cooling or misting systems are used to prevent heat stress. And though the soaking fans and cooling structures are effective, these management efforts are often too expensive to maintain.
As one of the scientists working on building a more heat-resistant beef cows, Mateescu searches for large sweat glands, short, slick hair and efficient blood flow mechanisms when choosing traits.
Researchers pick from a swarm of different characteristics, ranging from a cow’s average heart rate to their natural ability to repel flies. Searched and spliced and sewn together, these traits all boil down to a cow’s ability to combat heat and its consequences.
But genetically engineering our cattle is also extremely time-consuming and expensive — and it won’t be long before extreme heat events become dangerously common.
Looking Forward
The cattle ranching industry in Florida boasts a long and colorful past. Next year is the 500-year anniversary of the introduction of cattle to the state, marking five full centuries of history.
The continued longevity of the state’s cattle industry is critical to Florida's economy. In 2017 alone, the beef, dairy and allied cattle industries generated revenues totaling $16.8 billion, supporting over 100,000 full-time and part-time jobs.
This is why as global temperatures rise, it’s becoming more important to researchers like Mateescu and Thrift to keep our cattle cool. And though it may take time, they’re confident Florida will be able to build a better cow.
“Ultimately, when you try to fight mother nature, she’ll bite back,” Thrift concluded. “And without the right resistance, you won’t be in the business for very long.”
This story is part of the UF Thompson Earth Systems Institute's student-produced Earth to Florida newsletter that curates the state’s environmental news and explains what’s going on, why it matters and what we can do about it.
The University of Florida Thompson Earth Systems Institute is advancing communication and education of Earth systems science in a way that inspires Floridians to be effective stewards of our planet.
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Created with images by jodylehigh - "climate change drought climate" • Shayaden - "brahman bull cattle" • sasint - "livestock cows cattle" • IsaacTuray - "cows stream cattle" • Skitterphoto - "cow animal livestock"