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Wyoming state veterinarian provides animal health update at Fremont County event

by Wyoming Livestock Roundup

Riverton – The Fremont County Farm and Ranch Days took place Feb. 18-19, and during the event, educational speakers presented on topics ranging from pasture seeding to livestock updates. 

Wyoming State Veterinarian Dr. Hallie Hasel provided a Wyoming animal health update. Hasel discussed several livestock diseases impacting cattle, poultry and equine throughout the state.


“Our goal as the state vet office is to keep cattle in Wyoming marketable,” shared Hasel. “If cattle have trichomoniasis, their value drops considerably. It is our goal to make sure Wyoming cattle don’t have this problem and keep them healthy because Wyoming is an export state.”  

It is not unusual to have a herd in quarantine, she noted. 

Once a positive animal has been removed, state veterinarians test the entire herd two to three more times to ensure the herd remains negative.   

A positive animal doesn’t mean producers can’t sell anything, Hasel said. In addition, booster vaccinations do not trigger false-positive test results in cattle, she added.

“Cattle are vaccinated by 12 months of age, and in high-risk areas, a booster vaccination is administered at least six weeks prior to breeding. The adult is then vaccinated every three years,” she explained. 

In July of 2017, the Wyoming Livestock Board issued an order mandating bulls grazing on open and public allotments, or being traded or leased for reproductive purposes, are to be tested prior to breeding or change of ownership.  

Brucellosis updates 

“Brucellosis is a zoonotic disease which can be transmitted between animals and humans, often referred to as Mediterranean or undulant fever in humans,” she explained. “It’s a disease which causes abortion in cattle, elk and bison.” 

The biggest risk for cattle producers is during elk calving periods, typically February through early May. Contact with elk outside of this period doesn’t carry the same risk as it does during calving season, Hasel noted. 

Symptoms can vary and may include low-milk production, less thrifty cattle and arthritis, she explained. 

One of the primary benefits of the brucellosis vaccine is not disease protection, but abortion protection, she shared. 

“Vaccinated livestock can become sick with brucellosis, but when they are vaccinated, cattle are unable to spread it as much and the vaccine protects them from abortion,” said Hasel. “There is not a vaccine for wildlife, but there are ways to mitigate risk with elk.”

“What we need for brucellosis research is the ability to use an outdoor lab, and currently the disease is on the bioterrorism list; so, it can’t be researched in an outside lab setting,” she said. “It is a disease which affects both humans and animals.”

The state veterinarian’s office has applied to the federal government asking for brucellosis to be removed from the list, in order for research in an outdoor lab to occur. 

“If we export cattle out of the state with brucellosis, our ability to export cattle beyond our borders will be extremely difficult and costly for producers,” she said. “Vaccinating for brucellosis is important.” 

“One of the things we do for brucellosis mitigation in the state of Wyoming is encourage producers to develop a herd management plan,” shared Hasel. “If producers have a brucellosis plan in place it can help reduce cost.” 

The state veterinarian’s  office will work with producers to develop a herd plan to help mitigate brucellosis in the herd.  

In addition, the office can assist producers with waivers. For example, if producers live outside of a designated surveillance area (DSA) and their cattle graze in a DSA, cattle have to be tested in order to go back to the home place. 

If producers are unable to test prior to moving cattle, the state veterinarian’s  office can provide waivers, but producers need a brucellosis herd plan in place in order to be eligible, explained Hasel. 

She noted there has been elk mitigation efforts to decrease the risk of disease to Wyoming cowherds through fencing, hunting and booster vaccinations.

Avian flu 

While poultry is not a major industry in Wyoming, the state does have backyard flocks, shared Hasel. Recently, flocks in the eastern U.S. have tested positive for the disease. 

“Influenza is typically transmitted by wild birds, usually by ducks – they don’t typically get sick,” said Hasel. “But, Wyoming is in several fly-away patterns for wildlife bird species.”  

Hasel encouraged ranchers who own chickens to contact the state veterinarian’s office if birds become sick, as producers can lose a whole flock of birds within a few days. 

Cold-like symptoms may be seen and include watery eyes, runny beak, blue combs and a loss of appetite. When symptoms occur, Hasel encourages producers to contact a local veterinarian or the state veterinarian’s  office immediately. 

An animal disease investigation is at no cost to the producer. 

“We want to know what disease is there,” she said. 

In addition, the U.S. Department of Agriculture (USDA) has a Defend the Flock Program, which offers free tools and resources for following proper biosecurity practices when producers work with or handle poultry. 

Equine diseases 

As of 2021, several states in the U.S. have seen positive Equine Infectious Anemia (EIA) cases, with Texas having the most. 

Wyoming is currently disease free, but it’s still important to be conscious and aware of infection, as many horses are crossing the state’s borders, explained Hasel. 

“Looking at EIA trends from 2013 to 2020, the number of EIA horses the U.S. has are from race horses,” noted Hasel. 

Another disease affecting horses is piroplasmosis – a reproductive disease transmitted by ticks. Horses testing positive for EIA are also testing positive for this disease, said Hasel. 

“The state of Wyoming does have horse racing, and this is something we need to be aware of, because it’s out there,” she added. 

Equine Herpesvirus (EHV-1) is another disease impacting horses. Hasel reported EHV-1 is impacting horses across the state quite rapidly. She reported there is a positive case in Cody, and she encourages producers to be aware. 

There is not a vaccine which covers the neurological form of this disease, she noted. Horses can survive, but there is not a good treatment for neurological issues. 

Vesicular stomatitis is another disease spread by flies and causes blisters around the mouth, on the tongue and coronary bands. 

“The bottom line is if producers have a disease they don’t understand and have a sick animal or are losing livestock, they should contact the local veterinarian or state office,” concluded Hasel. “It doesn’t cost anything.” 

The state veterinarian’s office will soon be updating their website with the new rules and updates for producers.  

Brittany Gunn is the editor of the Wyoming Livestock Roundup. Send comments on this article to 

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