Gastrointestinal worms are among the most economically important health problems for ranched bison, but the drugs used to control them can lose effectiveness if used too often or without knowing which animals need treatment, a study led by the Texas A&M College of Veterinary Medicine and Biomedical Sciences warns.

The team surveyed bison producers, mostly in the southern and central US, about herds, pastures, nutrition, sourcing and parasite control. Nearly 90 percent deworm at least once a year and almost a third more than twice, yet diagnostic tools that show whether treatment is needed were rarely used. Producers mainly borrow practices from the cattle industry, although bison are harder and more dangerous to handle, so some use medicated feed.

"We have both anecdotal and diagnostic evidence showing that bison seem to have more parasitic issues compared to beef cattle," said Kaylee Kipp, now at Texas Christian University; severe infections cause diarrhoea and poor weight gain and can contribute to deaths. The researchers say the findings can guide more targeted deworming that slows resistance.

Photo: Baseball Bugs / Wikimedia Commons (Public domain)

Source: The Fence Post