On today’s Cow-Calf Corner is Rosslyn Biggs, DVM, OSU Cooperative Extension State Beef Cattle Specialist, and John Gilliam, DVM, with the OSU College of Veterinary Medicine, Food Animal Production Medicine and Field Service talking about researching internal parasites in cattle.
Anthelmintic (dewormer) resistance is a growing concern and OSU researchers are evaluating levels in Oklahoma beef cattle herds through ongoing studies. This research is important for the cattle industry in developing parasite management strategies that preserve the effectiveness of dewormers while maintaining cattle production levels for the future.
A recent study by Drs. John Gilliam, Jared Taylor, and Ruth Scimeca of the OSU College of Veterinary Medicine evaluating Oklahoma beef cattle herds provided evidence that internal parasite resistance is indeed present in the state.
Beginning in 2020, beef cow-calf producers submitted fecal samples for fecal egg count reduction tests (FECRT). Seventeen herds participated and all major classes of dewormers were represented. Anthelmintic administration practices were not controlled, and producers were encouraged to follow their standard procedures. Fecal egg counts (FEC) were determined using the Wisconsin method with a limit of detection of one egg per gram (EPG). Three herds were excluded from the final analysis as the FEC in those groups were too low.
Of the sixteen groups of cattle included in the final analysis, 13 exhibited resistance based on the average of individual FECRT. Based on the results of this small survey, anthelmintic resistance appears to be widespread in beef cow-calf herds in Oklahoma.
Currently the OSU beef cattle extension and veterinary teams are continuing work in this area. Drs. John Gilliam, Dave Lalman, Paul Beck, and Rosslyn Biggs are conducting a larger survey of Oklahoma herds to determine parasite resistance to different dewormers. Herds interested in participating can contact their extension county agricultural educator, area extension livestock specialist, or visit https://okstatecasnr.az1.qualtrics.com/jfe/form/SV_cAtiVIHwoLyow50 for more information on the sign-up.
The current study plans to collect data from at least 50 different groups of cattle dispersed around the state. Samples can be collected from now through first killing frost (generally early November) and then again through spring and summer 2024. Fecal samples will be collected from twenty to thirty animals within the same stage of production. Good handling facilities must be available for safe restraint of all animals and personnel collecting the samples.
