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. 2023 Nov:46:100937.
doi: 10.1016/j.vprsr.2023.100937. Epub 2023 Oct 9.

A fecal egg count reduction test in grazing beef steers using topical pioneer and generic eprinomectin and fenbendazole oral suspension

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A fecal egg count reduction test in grazing beef steers using topical pioneer and generic eprinomectin and fenbendazole oral suspension

Eva Wray et al. Vet Parasitol Reg Stud Reports. 2023 Nov.

Abstract

Many generic anthelmintics are commercially available; however, little information exists regarding product effectiveness compared to pioneer brands. The objective of this study was to compare the effectiveness of a generic eprinomectin to the pioneer eprinomectin, as well as to fenbendazole and fenbendazole in combination with the pioneer eprinomectin in grazing beef steers via a fecal egg count reduction test. Forty naturally infected steers were allocated into five treatment groups based on ranked fecal egg counts: 1. pioneer eprinomectin (Eprinex®, topical), 2. generic eprinomectin (Eprizero®, topical), 3. fenbendazole (Safeguard® 0.5% oral suspension), 4. combination of pioneer eprinomectin topical and fenbendazole oral suspension, 5. negative control. Fecal samples were collected on days -14, 0, 14, and 29. Data were analyzed using the MIXED procedure of SAS 9.4. Neither the pioneer nor the generic eprinomectin groups reached a 90% fecal egg count reduction (FECR) throughout the study with reductions of 50% and 11% for pioneer eprinomectin and 79% and - 5% for generic eprinomectin at days 14 and 29 post-treatment, respectively. Both the fenbendazole and combination groups showed 98% and 99% FECR, respectively, at 14 days post-treatment; these reductions dropped slightly at day 29 post-treatment to 94% and 89%, respectively. Primarily Cooperia punctata, Cooperia oncophora and Ostertagia ostertagi larvae were recovered from the coprocultures across all treatment groups. Interestingly, the proportions of C. punctata and C. oncophora essentially demonstrated a post-treatment reversal in the both the fenbendazole and combination treatment groups when comparing days 0 and 29, demonstrating prepatency period differences or a fenbendazole treatment effect.

Keywords: Cattle; Eprinomectin; Fenbendazole; Nematodes.

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Conflict of interest statement

Declaration of Competing Interest The authors declare no conflict of interest. No endorsement of any product mentioned in the article is made by the authors nor the University of Arkansas.

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