Effect of fenbendazole on shedding and embryonation of Ascaris suum eggs from naturally infected sows

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Animal Science, Veterinary Diagnostic and Production Animal Medicine

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Journal of Swine Health and Production





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Objectives: To determine reduction of Ascaris suum egg shedding and ovicidal effects in naturally infected commercial female breeding swine treated with fenbendazole.

Materials and methods: Five shedding and three embryonation experiments across three commercial sow farms were conducted. Ascaris suum-infected sows were allocated to four treatments: untreated controls; 545.5 mg fenbendazole, 1 day (Treatment 1); 545.5 mg fenbendazole, 3 consecutive days (1636.5 mg total) (Treatment 2); and 1636.5 mg fenbendazole, 1 day (Treatment 3). Fecal samples were collected and evaluated by a standard flotation method (shedding study) or eggs were isolated and incubated (embryonation study) to determine embryonation rates. Groups were compared for time-to-negative (Kaplan-Meier survival analysis); percent negative (chi-square analysis); environmental burden (analysis of variance); and embryonation rates (analysis of variance).

Results: Time-to-negative ranges were 9.3-13.1, 8.9-13.1, and 9.8 days post treatment (DPT) for treatments 1, 2, and 3, respectively; control ranges were 13.4-28.2 DPT. Treatment sows were 90%-100% negative, compared to 0.0%-28.6% of controls. Environmental burden ranges were 7.0%-60.9%, 13.9%-60.8%, and 29.3% (treatments 1, 2, and 3, respectively) and 60.4%-219.0% for controls. All treatment values differed from controls (P < .05), but not from each other. Embryonation rates were lower for treatments than controls at 6 and 8 DPT (P < .001).

Implications: Fenbendazole at various dosages is effective against A suum infections in sows. Treatment should begin 14 days prior to movement into clean farrowing facilities. Under the conditions of this study, fenbendazole demonstrates ovicidal activity against A suum at 4-8 DPT.


This is an article from Pittman, Jeremy S., Gil H. Myers, Kenneth J. Stalder, and Locke A. Karriker. "Effect of fenbendazole on shedding and embryonation of Ascaris suum eggs from naturally infected sows." Journal of Swine Health and Production 23, no. 5 (2015): 252-263. Posted with permission.

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American Association of Swine Veterinarians



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