A new study led by researchers at the Texas A&M College of Veterinary Medicine and Biomedical Sciences (VMBS) has uncovered important gaps in how gastrointestinal parasites are managed in North American bison. Published in the journal Veterinary Parasitology, the research examined the practices used by bison producers to control parasites, offering insights that could lead to more effective and targeted deworming strategies. The study also highlights the need to slow the development of drug resistance, a growing concern in livestock management. The findings provide a clearer picture of how bison are managed across the southern and central United States, identifying areas where parasite control could be improved while preserving the limited deworming drugs available. Gastrointestinal nematodes, or roundworms, are a major health issue for bison, according to Dr. Kaylee Kipp, a recent VMBS doctoral graduate and associate professor of ranch management at Texas Christian University. Reports from producers and veterinary diagnostics suggest that bison may face more parasitic challenges than beef cattle. These parasites can cause symptoms like diarrhea, poor weight gain, and reduced productivity, and in severe cases, they can even lead to the death of adult bison. Despite the impact of parasites on bison health, there has been limited research on how producers manage them, especially in the southern U.S., where most of the surveyed operations are located. To better understand these management practices, the research team surveyed bison producers about various aspects of their operations, including herd size, pasture management, nutrition, and how they handle parasites. The survey found that nearly 90% of producers deworm their bison at least once a year, and almost one-third deworm more than twice annually. However, few producers use diagnostic tools to determine if treatment is actually needed. Many rely on practices adapted from the cattle industry, even though bison are more difficult to handle, making frequent deworming challenging. Some producers use medicated feed to administer dewormers, which is a common practice in cattle but less studied in bison. Researchers are particularly concerned about the growing problem of anthelmintic resistance, where parasites become immune to the drugs used to kill them. Repeated treatment can increase the number of resistant parasites over time. According to Dr. Guilherme Verocai, an associate professor at VMBS and director of the Parasitology Diagnostic Laboratory, deworming should be one part of a broader strategy for parasite control. Diagnostic tests, such as fecal exams, can help identify which parasites are present and whether treatment is necessary, allowing for more targeted and effective use of dewormers. This approach can also help reduce the pressure on parasites to develop resistance, preserving the effectiveness of available drugs. Another strategy researchers hope to promote is the use of "refugia," which involves maintaining a population of parasites that have not been exposed to deworming medication. This helps keep parasite populations genetically diverse and less likely to develop resistance. However, fewer than 10% of surveyed producers reported using this method intentionally. The study emphasizes that there is no one-size-fits-all approach to bison management, as each herd has unique characteristics, including size, environment, and parasite dynamics. The goal is not to eliminate treatment but to make informed decisions based on the specific needs of each herd. By establishing a baseline of current practices, the researchers aim to develop bison-specific guidelines that protect both animal health and the long-term effectiveness of deworming medications.