The Drewery Lab develops eco-friendly cattle feeds to cut emissions and costs.
The old red barn at the Freeman Center looks like it could be the set of a classic Western movie. Inside the low-slung structure, livestock pens house black Angus steers. The cattle nap, glance around curiously, and occasionally munch on hay.
But a closer look reveals an unusual twist: Each steer has a plastic port its side. Called a cannula, the hole allows researchers to reach into the animal’s rumen and remove the partially digested contents of its stomach for examination.
Dr. Merritt Drewery, associate professor of applied animal science, and her students in the Drewery Lab have been conducting research on cannulated steers at the Freeman Center for the past six years. They’re at the forefront of studying new types of cattle feed that are sustainable, effective, and affordable.
“Our lab focuses on enhancing the sustainability of beef cattle production,” Drewery says. “We try to evaluate novel feeds that are less water intensive and that require fewer natural resources to produce.”
Cattle raised for beef typically require protein supplements to enhance the nutritional value of their natural forage and hay. Most supplements contain additives like soybean meal, cottonseed meal, or corn.
Drewery’s goal is to find alternative additives that require less water to produce and are cheaper because they’re not part of human markets. (For example, demand for soybeans in human food products drives up the price.) To that end, she and her team have published a series of papers as they study the viability of protein sources ranging from insects to hemp to biochar.
Drewery says she studied black soldier fly and mealworm larvae—and even insect sheddings and excrement—as protein additives in part because most humans won’t eat them. Over the course of six studies, she found that the insects are a good protein source for cattle. But she also found that insect-rearing industry hasn’t grown big enough yet to provide insects at an affordable price for the agricultural market.
When it comes to hemp, Drewery’s team recently studied whether the stalks and leaves of hemp plants could work as a protein additive without unintentionally introducing the cannabinoids that can have psychoactive effects in humans (like in marijuana).
“We’re interested in hemp because it’s very hardy crop that’s drought-resistant and doesn’t require a lot of water or pesticides,” Drewery says.
In two recently published studies, Drewery determined that hemp stalks make good livestock feed, but she also found that cannabinoids lingered in some steers’ tissue. Drewery says future studies, funded by a new $300,000 grant from the U.S. Department of Agriculture, will focus on how long cattle will need to be removed from hemp feed to safely process them for beef.
The Drewery Lab is also studying cattle feeds that could reduce methane created by cattle digestion and manure, emissions that contribute to harmful greenhouse gases. That’s where biochar comes into the picture—the same burned wood chips that Drewery’s colleagues at the Freeman Center are studying for their benefits as a soil amendment to help regenerate pastures across the ranch.
This summer, Drewery and Dr. Emily Fowler, a post-doctoral researcher in the Drewery Lab, are conducting a study of biochar feed additive to look at how it impacts microbial communities in the cattle’s rumen.
“We’re really interested to see if it downregulates methane production in cattle,” Drewery says. “But then we’re also interested to see if it amends the feces so that if they’re spread on the pasture, we’ll have better forage growth.”
Artificial Intelligence is revolutionizing how people work across the economy, and ranching is no exception. The AnimalCareBot project at Freeman Center is developing robots to monitor cattle herds.
Dr. Merritt Drewery, associate professor of applied animal science, is co-project director on the effort with Dr. Heping Chen, Dr. Bahram Asiabanpour, and Dr. Damian Valles of the Ingram School of Engineering. The U.S. Department of Agriculture is funding the project with a four-year, $400,000 grant.
Drewery worked with her students to place cameras in Freeman Center pastures to record the cattle herds and then label hundreds of hours of videos with descriptions, such as laying down, grazing, and fighting. The engineering team is now working to build a hardy robot that can navigate pastureland while also processing the video data into an AI model that will allow the robot to identify cattle behavior and send reports to ranchers, whether it’s a herd count or alerting them to a problem.
Along with providing a tool for ranchers, the project aims to get more science and engineering students interested and equipped to work in the agricultural industry.
“A rancher doesn’t see their cows every day, and they may not see some cows every month,” Drewery says. “That’s totally normal for extensively managed ranges. And so, can we make a robot that monitors the conditions?”
