Protecting Domestic Sheep, Saving Wild Herds:

Protecting Domestic Sheep, Saving Wild Herds

The Race for a Movi Vaccine

By Chester Moore

In the quiet barns and research pens of Montana State University, a high-stakes experiment is underway that could protect the health of domestic sheep, preserve the survival of wild bighorns, and change the way veterinarians combat a stubborn issue. The culprit is Mycoplasma ovipneumoniae (Movi), a respiratory pathogen notorious among wildlife biologists and ranchers alike. In domestic flocks, it’s often attributed to some respiratory issues, slower weight gain, lower reproduction and overall loss in herd vitality.

In bighorn sheep the effects can be devastating to entire herds. For decades, wildlife managers and livestock owners have been caught in a tense balancing act, trying to keep the two worlds apart to prevent disaster.

Dr. Diane Bimczok, a veterinarian and mucosal immunology researcher at Montana State, thinks there might be another way through science that doesn’t rely solely on fences and geography. If her current trial is successful, a vaccine could do what antibiotics have failed to achieve: prevent Movi from taking hold.

From Antibiotics to Immunity

When Bimczok first considered attacking Movi head-on, antibiotics seemed like a natural place to start. But her graduate students’ research quickly shut that door. They identified two primary reasons why antibiotics would not be effective in solving the problem. First, Movi forms biofilms, which are sticky, matrix-like layers of bacteria that adhere to surfaces in the respiratory tract, making them notoriously hard to kill.

“Think about the gritty feeling on your teeth when you wake up after not brushing the night before,” she said. “That’s a biofilm, and you can’t rinse it away. You must scrub it off, but inside a sheep’s lungs, there’s no toothbrush.” Second, even outside biofilms, Movi can rapidly develop antibiotic resistance, even within a single infection cycle. That meant the bacteria weren’t just dodging treatment; they were learning how to do it better the next time. “Antibiotics were out at that point,” Bimczok said.

Prevention was the only viable strategy.

Collecting vitals on vaccinated sheep

DVM student McKenna Quirk collecting vital signs to assess potential systemic adverse affects of the vaccine (there were none).

Building a Vaccine, Strain by Strain

The current trial originated from an international collaboration that dates to Bimczok’s time studying in Germany. While on sabbatical there last year, she reconnected with Professor Martin Ganter of the University of Veterinary Medicine Hannover, an expert in small ruminant medicine. Ganter’s clinical teams had already used custom-made Movi vaccines in Iceland and parts of Europe. These formulations are tailored to the specific bacterial strains found in each region. That idea was crucial because Movi isn’t uniform.

“The strains in Iceland aren’t anywhere close to the strains we have in Montana,” Bimczok said. “Even within Montana, the genetic variation is huge.”

This variation meant there would be no one-size-fits-all shot; any effective vaccine for the western U.S. would have to be built from local bacterial samples. In the fall, Bimczok’s team isolated and genotyped multiple strains from domestic sheep in Montana, growing them under controlled lab conditions before shipping them to a German biotech company.

There, two vaccine versions were developed: one using whole, killed bacteria in a standard adjuvant, and another constructed from bacteria grown as biofilms that were designed to include the unique antigens produced by biofilm-forming bacteria.

The 21 Sheep Trial

The trial began in June. Twenty-one pathogen-free domestic sheep raised in MSU’s secure research facility were divided into three groups of seven. One group received the standard killed-bacteria vaccine, one group received the biofilm-based vaccine, and a third group served as the control, receiving only saline.

Each vaccinated sheep got two doses, spaced several weeks apart. Side effects were minimal. Some animals developed mild fevers, like what people might experience after a COVID-19 shot. Swelling at the injection site was less than with many other livestock vaccines. Preliminary blood tests showed that vaccinated sheep developed antibodies against Movi. In late July 2025, the team initiated the challenge phase. Using an endoscope, they introduced live Movi directly into the sheep’s lungs.

From here, it’s a waiting game. The sheep are being closely monitored for temperature changes, behavior, weight gain, and respiratory symptoms. By early fall, the study will reach its endpoint, involving necropsies and detailed sampling to determine whether the vaccinated animals resist infection better than the controls.

Below, Dr. Bimczok's team performing blood sample collection to determine antibody in our experimental SPF sheep to measure antibody concentrations.

Collecting blood sample

Drawing blood from domestic sheep

Why This Matters for the Wild

For wildlife managers, the stakes are high. When bighorn sheep encounter Movi, the disease often spirals into full-blown pneumonia, killing lambs for years afterward and stunting herd recovery. Entire translocation projects can be derailed if domestic sheep are present in the vicinity.

A vaccine could change that calculus. “If you know where these conflict zones are, you could vaccinate the domestic sheep in that area against their own local strain of Movi,” Bimczok said.

This latter-focused approach could both improve livestock production and reduce the risk to wildlife which is a rare win-win in a field often marked by tension between agriculture and conservation.

A New Kind of Collaboration

While this study involves a global level of collaboration, another collaboration is emerging between wild sheep advocates and domestic sheep growers. In Montana, a new chapter is being written. Instead of pointing fingers across the fence line, both sides are working side by side to solve their shared challenges. Kurt Alt, Conservation Director for Montana and International Sheep & Goat Programs at the Wild Sheep Foundation, is excited about what’s happening, really for the first time.

“What’s going on right now is the Montana Wool Growers and the Montana Wild Sheep Foundation decided to work together instead of fighting, instead of pointing fingers at each other, pointing fingers at the problem,” Alt said. That commitment has already translated into action. Montana Fish, Wildlife & Parks, backed by support from wool growers and the Wild Sheep Foundation, has launched a five-year, $8 million initiative to safeguard sheep on both sides of the fence.

The efforts cover a wide range of priorities, from managing distribution and herd augmentations to fostering new herd growth, improving habitat conditions, addressing pathogens and predation, and interactions between domestic and wild sheep.

Together, these efforts are laying the groundwork for practical, science-based solutions that reduce disease risk while maintaining viable ranching operations. And yet, even with all these projects ongoing, managers know the fight against disease isn’t finished.

That’s where science, such as Dr. Diane Bimczok’s vaccine research, fits in. Her work represents the kind of forward-looking, science-based tool that could eventually be layered onto Montana’s collaborative framework. In many ways, the state’s new culture of cooperation has created the perfect proving ground. In this environment, ranchers, wildlife managers, and researchers can collaborate to test solutions and share successes.

Students in protective gear

Ph.D. student Ms. Sobha Sonar and postdoctoral fellow Dr. Hannah Marahrens in personal protective equipment for working in the large animal BSL-2 facility, the Johnson Family Livestock Facility.

Proven Abroad, Awaiting Proof at Home

In Iceland, where similar vaccines have been used for years, farmers report better lamb survival rates and improved growth. Those efforts haven’t been paired with the kind of rigorous, blinded trials that Bimczok’s team is conducting now, but the anecdotal evidence is strong enough that ranchers continue to request the shots. In the U.S., interest from the domestic sheep industry is growing. Vaccines are relatively cheap compared to other management interventions, and sheep already receive multiple vaccinations for different diseases. Adding one more, if it proves effective, could be a straightforward decision for many producers.

For now, Bimczok is hopeful but realistic. The trial could show that the vaccine prevents illness outright, reduces bacterial load, or perhaps only limits disease severity. Any of those outcomes would be a step forward. The idea that livestock health and wildlife conservation might align is appealing not just scientifically, but socially.

As Canadian conservationist and former British Columbia Wildlife Veterinarian Helen Schwantje has found, many domestic sheep producers are motivated by both economic and ecological concerns as they want healthy flocks, but they also care about the wild herds on the landscape.

If the Montana trial proves successful, it could mark the beginning of a new era where science and cooperation walk hand in hand. With wool growers and wild sheep advocates finally on the same side of the fence, and researchers like Dr. Diane Bimczok pushing the boundaries of prevention, the future of sheep on both ranges looks brighter than it has in decades. Montana is showing the rest of the West what’s possible: that long-standing conflicts can give way to trust, that ranchers and wildlife managers can work as partners, and that science can provide the tools to make it all last.

The battle against Movi is far from over. Still, with collaboration and innovation aligned at both regional and global levels, there’s a genuine chance to protect domestic flocks, restore wild herds, and ensure these monarchs of the mountains continue to thrive for generations to come.

Contributing Author: Chester Moore is an award-winning wildlife journalist, wildlife photographer, and lifelong hunter from Texas. He operates the Higher Calling Wildlife® blog and podcast and contributes to many outdoors publications.