Research Highlights Challenges in Managing Parasites in Bison

Gastrointestinal parasites are a significant health threat to North American bison, often leading to severe issues such as diarrhea, poor weight gain, and even mortality. Dr. Kaylee Kipp, a recent PhD graduate from VMBS and now an associate professor at Texas Christian University, stressed the economic impact of these parasites, noting that bison seem to exhibit more parasitic issues than beef cattle.

The study provides a closer examination of parasite management among bison producers particularly in the southern and central United States, areas where prior research has been limited. Most existing studies focused on larger herds in northern states and Canada.

Dr. Guilherme Verocai, an associate professor at VMBS, highlighted the necessity of understanding the operational dynamics of different herd sizes. The research team surveyed bison producers on various factors including herd demographics and parasite control practices. They found nearly 90% of producers dewormed their bison at least once a year, with about one-third deworming more than twice annually. However, diagnostic tools to assess the need for treatment were rarely utilized.

The survey revealed that many bison management practices are adopted from the cattle industry, despite unique challenges presented by bison. Handling difficulties often lead some producers to use medicated feed for deworming instead of traditional methods. Additionally, there is limited information on the appropriate use of deworming drugs specifically for bison, with only one product approved by the FDA for treating gastrointestinal nematodes.

Researchers express concern about anthelmintic resistance, where parasites evolve to survive treatments. Repeated use of dewormers can shift the parasite population towards those that resist drugs. Verocai pointed out the urgency in diversifying approaches to parasite management, as producers have a limited selection of dewormers and few new options are on the horizon.

Diagnostic testing, such as fecal analyses, is one tool that can help producers make safer treatment decisions by identifying which parasites are present, ideally allowing for more targeted deworming. Verocai noted that while this process may seem time-consuming, it can potentially reduce drug usage and costs over time.

The concept of refugia, maintaining a portion of untreated parasites, is another strategy to mitigate resistance. However, fewer than 10% of herd managers reported employing this method. Kipp emphasized the importance of looking towards sustainable practices that consider long-term effects rather than just immediate needs.

The research encourages bison producers to adopt tailored management practices based on the specific characteristics of their herds, ultimately striving for solutions that safeguard animal health while ensuring the longevity of deworming options.