On the surface, James West and Warren Gill might not seem like the most natural pair to team up in an effort to overhaul the way the world eats.
West, an associate professor at Vanderbilt University School of Medicine, has spent most of his career working with human diseases — particularly lung diseases — and genetic engineering.
Gill, a professor as well, is less interested in human health. Born on a Tennessee cattle farm, Gill has worked as a rancher and cattle specialist for over three decades, managing his family farm since 2000 and serving as department chair of the Middle Tennessee State University agriculture department for the past eight years.
In 2012, out of the blue, Gill received a phone call from West, asking for a meeting. West came into Gill’s office at MTSU and explained the research he was doing with genetic engineering, like editing genes to give animals the same diseases as humans and using bio-markers to find both beneficial and deleterious genes. Gill was intrigued, and the two set out working together to create a gene test for copper deficiency — something that has long plagued cattle herds throughout Tennessee.
The next year, Gill attended a conference in Orlando, where he heard other farmers and cattle ranchers talk about the impact of climate change on livestock. It had been nearly two years since the summer of 2011 — a particularly hot summer where heat waves claimed the lives of thousands of cattle across the Midwest. Ranchers and farmers were beginning to think about raising cattle in warmer climates, and wondering what could be done to strengthen their herds against rising temperatures.
When Gill got back to Tennessee from the conference, he asked West a question.They had been trying to increase heat tolerance through traditional breeding methods, by breeding animals with lighter coats, or by crossing heat-tolerant breeds with especially productive breeds like Angus, but weren’t having much luck.
“Can you make me a white Angus?”
West thought about it for a minute. A cautious person, he didn’t want to promise Gill something he couldn’t deliver.
But after a few days of researching, West came back with an answer.
“I think we can do it,” he told Gill, and
Climate Adaptive Genetics — the project to genetically engineer a heat-tolerant, high-performance Angus — was born.
How Do You Double Meat Production Without Doubling Resources?
Black angus is one of the most popular, productive breeds of beef cattle, but it’s also not very heat tolerant.
CREDIT: SHUTTERSTOCK
Forty years ago, beef ruled the American diet, with each person eating an average of
91 poundsof beef a year in 1976. Over the last four decades, however, despite the influx of low-carb and Paleo diet fads, beef consumption in the United States has steadily declined. In 2012, the average American consumed just 52 pounds of beef a year, down 43-percent from the 1976 high.
But while beef consumption in the United States has fallen, global beef consumption is on the rise. People that live in developing countries tend to eat much less meat and animal products than those in developing countries, but as the global economy continues to grow — spurred by advances in technology, trade liberalization, and population growth among other factors — meat consumption in developing countries
continues to rise.
To environmentalists, an increasing demand for meat is a huge problem, because meat production has a huge environmental footprint. Ruminants, like cows, digest food by first fermenting it in a specialized stomach, a process that helps extract nutrients from tough plants but also releases methane as a byproduct. Methane is an incredibly potent greenhouse gas, some
25 times more powerful than carbon dioxide over a 100 year period. Globally, the livestock sector is responsible for
14.5 percent of the world’s greenhouse gas emissions, and cattle produce 65 percent of the livestock sector’s emissions.
But livestock production is also economically beneficial, especially for poor communities. According to the FAO, livestock production creates livelihoods for 987 million poor people living in rural areas — roughly 36 percent of the world’s poor. In 2014, Slate’s Laura Anderson took a look at what might happen if everyone suddenly stopped eating meat. There would be instant good news: the decline in antibiotic-resistant infections, a surge in the availability of new land, a sharp drop in livestock-related greenhouse gases. But there would also be negative impacts: a decline ineconomic security for farmers who don’t have an alternative to livestock, and a drop in food security.It’s not just cow gas that is responsible for those emissions — there’s the fossil fuel burned throughout in the supply chain, the methane released from cow waste stored in temporary pits or lagoons, the carbon lost when vast forests are felled to make way for livestock grazing. There’s the soil degradation that comes from grazing — since 1945, the United Nations Environment Program estimates that 20 percent of the world’s grazing lands have become degraded. And, in an increasingly water-scarce world, there’s the strain livestock production places on water resources, using eight percent of the world’s freshwater.
That leaves food security and livestock specialists with a conundrum: for environmental reasons, we can’t keep producing cattle the way we’ve been doing it, and while we can work to reduce the consumption of animals, we can’t cease cattle production completely. To meet increasing demands of population growth, agricultural production is actually going to need to grow by 60 percent by 2050, while enduring higher temperatures, competing for less land, and facing demands that the industry consume fewer natural resources.
The livestock industry is a driving factor in climate change — but can it adapt to a changing climate?
Finding — And Preserving — The Right Gene
Irene Hoffman, who leads the Animal Genetic Resources Branch of the U.N.’s Food and Agricultural Organization, thinks it can. The key, she says, is using genetic resources to make livestock more efficient — not just more productive, but better at maintaining productivity in extreme environments.
“Most of the breeds that are really the high-output breeds that we see today, they come from temperate areas,” Hoffman told ThinkProgress. “If you breed an animal, like we have done, to have a high performance, this brings with it some physiological changes. A body can only do so much with dealing with stress and high performance. That means, naturally, if you dedicate a lot of your body energy into the production of one product, other body functions reduce.”
The breeds that dominate the U.S. cattle markets —
Angus and Herefords — belong to a subspecies of cattle known as
Bos taurus. They’re productive breeds, effective at converting feed to muscle mass and exhibit vigorous growth from birth onwards. But that productivity comes at a price, as they’re not well-adapted to living in hot, humid conditions.
In tropical areas, cattle belonging to the subspecies Bos indicus are more widely used. Popular Bos indicus breeds like the Brahman or Nelore are useful for ranchers in hotter parts of the world because they are more heat-tolerant than their Bos taurus counterparts, but they take longer to reach puberty and yield less meat, milk, and offspring than a Bos taurus.
Brahman, a breed of Bos indicus cattle, is heat resistant but not very productive.
CREDIT: SHUTTERSTOCK
But outside of the big names — the Angus and Brahmans of the commercial livestock world — are some 800 recognized breeds of cattle. Most of these are local breeds that are often better suited to the environment, whether through heightened heat tolerance or increased disease resistance.
But local breeds are
disappearing, as the livestock industry has long been dominated by systematic breeding that places preference on a few traits at the expense of many.
According to the FAO, up to 30 percent of global livestock breeds have populations below 1,000 and are at risk of extinction — and some local breeds could go extinct without anyone knowing if they possess genetics that might be especially good for climate adaptation.
“We can only do genetic improvement on traits we measure,” Alison Van Eenennaam, an animal genomics and biotechnology cooperative extension specialist with UC Davis’ Department of Animal Science told ThinkProgress. “We keep great track of traits that are important economically, like weaning weight and marbling. Where we don’t have good databases is, for example, resilience. How do you measure that? How do you rank that?”
A few places around the world are trying to tackle that issue head on, by creating genetic databases and genebanks in order to categorize and preserve the traits of rapidly disappearing livestock breeds. In 1987, the FAO launched its Domestic Animal Diversity Information System, meant to compile information about specific breed traits around the world. As of 2013, the database contained information about 12,345 breed populations from 182 countries around the world. But that information tends to skew in favor of breeds from developed countries — in developing countries, research about livestock traits tends to be less advanced, making it more difficult to correctly categorize traits, or know what traits might be useful in different environmental scenarios.
“For developing countries, we are very much at the descriptive state. We only know that these animals perform under extremely harsh environments with very high temperatures and not enough feed and not much water and they still produce something,” Hoffman said. “That’s a very indirect way of measuring performance.”
And categorizing traits is just one step — after a useful trait is identified, it still needs to be preserved. That’s where places like the
National Animal Germplasm Program come in. Started in 1999, the NAGP is like a seed bank for livestock; throughout the halls of its repository in Fort Collins, Colorado, are hundreds of thousands of samples from about 25,000 animals around the world — frozen semen, embryos, ovaries, and tissue that could be used to reconstitute livestock populations or simply lend a useful gene to an intrepid breeder.
But Gill worries that, with the disappearance of local and heritage breeds, finding the right traits to create a robust cow might become more and more difficult.West and Gill didn’t have to go to the frozen halls of Fort Collins or search the FAO’s database to find the genetic traits they needed for their white Angus — they just had to cross the Tennessee border and head to an Alabama farm, where a breeder had a few of the white-haired Silver Galloway cattle they needed.
“What if somebody had done away with the Silver Galloway? We’d have been stuck,” he said. “Thank goodness for the people that were wise enough to keep these around. Who knows what’s going to be important in 50 to 100 years.”
Creating A Climate-Adapted Cow
For a long time,
Bos taurus’s poor performance under heat stress wasn’t a pressing issue for the livestock industry. Large commercial operations have been able to
mitigate heat stress issues through things like fans, sprinklers, and building shade structures. In places like South Dakota that might see periods of extreme heat for only a brief period of time, measures like these can often be enough to keep cattle safe from heat stress, Joe Cassady, head of animal science at South Dakota State University, told ThinkProgress.
In places like Texas or Louisiana, however, where heat and humidity happen more frequently, external measures might not be enough — and, if climate change brings
increasingly long stretches of heat to the American Midwest, external management might not be enough there, either. In 2011, one of the hottest summers on record sent temperatures rocketing across the Central and Eastern United States, causing the death of thousands of cattle. To make matters worse, during periods of extreme heat, people tend to use more power. This places excessive strain on the grid that can lead to power outages, shutting off things like sprinklers and fans.
Heat tolerance in cattle is an incredibly complicated matter. Scientists and ranchers have an idea of traits that can contribute to heat tolerance — metabolic rates, ability to shed their coats, hair color — but there is no silver bullet. “Physiologically, there are no completely isolated reactions to heat,” researcher W. Bianca
wrote in 1961, “because of the relationships existing between the various body processes.” Several independent studies, however, have managed to link heat tolerance — at least in part — to the the color of a cow’s hair. A
2011 study in Australia, for example, found that cattle with tan and white-colored coats had significantly lower body temperatures, even while in full sunlight without shade, than black and red-haired counterparts.
So when Warren Gill asked James West to make him a white Angus, he wasn’t just interested in aesthetic properties — the two believe that through gene editing, they can create an Angus with a white, slick coat and a protective black hide that would allow ranchers in tropical areas to raise productive Angus cattle in warmer climates.Part of what makes an Angus so heat intolerant is its black hide and black hair, which trap heat like a dark shirt on a hot summer day. “The laws of physics do not cease to exist in cattle,” Cassady said. “Black absorbs sunlight to a greater degree than other cattle, so black hided black haired cattle are going to be more susceptible to heat stress.”
“That ought to increase the point at which Angus begin to feel heat stress from 75 degrees [Farenheit] to 90 degrees,” West told ThinkProgress. “It makes the cattle more comfortable, it reduces the need for water, and it reduces the need to clear land.”
And, perhaps best of all in West’s estimation, gene editing could create a heat-tolerant cow much more quickly than traditional breeding. To create a white-haired, black-hided Angus, West and Gill simply take skin cells from a champion Angus and alter its DNA, adding the genetic traits of a slick coat from an African cattle and white coat from a Scottish Silver Galloway cattle. To edit the DNA, they use a technique known as “transcription activator-like effector nuclease” — TALEN, for short — which damages existing DNA and uses the DNA that has the intended change — in this case, the white hair of the Silver Galloway — to repair the damage. The skin cell is then turned into an embryo, through cloning, and implanted into a female cow and carried to term.
“What we’re doing here is not something you couldn’t do with breeding, but it would be a 40 or 50 year breeding project,” West said. In contrast, gene editing could create a slick, white-haired champion Angus in a single generation.
Gill thinks about it in slightly different terms, recalling his grandfather, who was a master horse breeder.
“He was always looking for those traits that made the horse better for pulling, or running, or a gentle ride. Essentially we’re not doing anything different. We’re trying to find those traits that help the animals, improve the quality of animals life, and make things a little easier for animals and humans,” he said. “We can just do it a little quicker than my grandfather could do it.”
So How Close Are We To Certified (White) Angus Beef?
If today’s estimates are right, in 50 to 100 years, the world will be both hotter and more crowded — and ranchers will be pushed to producing more livestock with fewer natural resources.
That’s a challenge that West thinks the livestock industry can — and should — tackle.
“We’ve got to be able to produce the protein that people want without tearing up the planet to do it,” West said. “The only way to make that work, without destroying the rest of the wild spaces on the planet, is to be able to produce twice as many animals on the same land, and the only way you can do that is by improving the animals themselves.”
But Gill and West still have a number of hurdles to jump through before they see their dream of a white Angus become a reality. First, there’s actually implanting the embryos, which will happen simultaneously in labs in the United States and Brazil.
If that goes according to plan, and 270 days later two white Angus calves are born, the cattle will face another unprecedented obstacle: obtaining approval from the FDA, which has never approved a genetically engineered animal. The FDA released its
regulatory guidelines for genetically engineered animals in 2009, before gene editing showed real commercial potential — as such, it’s unclear if the FDA’s existing guidelines even cover gene editing.
Gene editing, while more precise than other genetic engineering techniques like gene guns, still isn’t one-hundred percent foolproof. Michael Hansen, a senior scientist with the Consumers Union — the policy arm of Consumer Reports — worries that gene editing can lead to off-target consequences, where sequences of DNA identical to the sequence that the scientist wants to replace are also unintentionally deleted during the editing process. Hansen told ThinkProgress that it’s impossible to know what consequences would occur when unintentionally deletion and replacement happens during gene editing, because it’s so specific to the particular DNA sequence being edited.
“Transgenesis works best if few, very well known genes are involved. Changing the color of a breed … is relatively easy and has been done by conventional breeding, as most colors follow simple Mendelian genetics,” Hoffman said. “However, climate change adaptation in general involves many traits and genes that influence morphology, physiology and behavior of the animal; they are more difficult to select for.”Another hurdle — perhaps the most important — will be proving that a white-haired, slick-coated Angus really does have better heat tolerance than a black Angus would. West and Gill are confident, but other animal scientists worry that the solution might be too simple.
Van Eenennaam is also skeptical that white hair is the only thing necessary to make cow more tolerant to heat.
“Conceptually, I’m not sure that having black fur isn’t the only thing that makes [an Angus] less heat tolerant,” she said.
Gill and West acknowledge that there are undoubtedly a complex mix of factors that make one cow more heat tolerant than another, but say that it’s important to start making changes somewhere.
“At this point, we are focusing on hair color, skin color, and hair length, knowing perfectly well that there are many factors involved in climate adaptability,” Gill said. “We will take those into consideration as time goes on, but you gotta crawl before you run.”
But even if West and Gill can successfully implant the edited embryos, obtain FDA approval, and prove that the white Angus truly is more heat tolerant, they’d likely face an uphill battle for consumer acceptance, at least in the United States. To qualify as
certified Angus beef — one of the
most recognized brands of beef in the country — a cow either has to trace its DNA back to Angus parentage, or be at least 51 percent black — raising some question as to whether or not West and Gill’s white Angus could technically qualify as a certified Angus. Even if it does qualify, the public might be wary of an animal created through gene editing, even when those genes come from the same species (West initially wanted to use a gene for white hair from a
Leghorn chicken, but thought better of it).
West and Gill hope that gene editing will be more readily accepted than genetically modified products because gene editing is so similar to traditional breeding, just on a faster timeline. Gill also sees a market in places like Brazil or India, which haven’t been able to use productive breeds like Angus due to their lack of heat tolerance.
“We have hot climates already and billions of people in those hot climates that would like to have these quality animals,” Gill said. “Climate change may have spurred some of our thinking, but that probably is not as important as feeding the world.”
Source: http://thinkprogress.org/climate/2015/07/02/3653871/climate-change-livestock-breeding/
