Veterinary Parasitology 97 (2001) 261–268 Anthelmintic resistance on goat farms in Georgia: efficacy of anthelmintics against gastrointestinal nematodes in two selected goat herds Thomas H. Terrill a,∗ , Ray M. Kaplan b , Michael Larsen c , Oreta M. Samples a , James E. Miller d , Seyoum Gelaye a a School of Agriculture, Home Economics and Allied Programs, Fort Valley State University, Agricultural Research Station, Fort Valley, GA 31030, USA b College of Veterinary Medicine, University of Georgia, Athens, GA 30602, USA c Danish Center for Experimental Parasitology, The Royal Veterinary and Agricultural University, Frederiksberg C, Denmark d Department of Epidemiology, School of Veterinary Medicine, Louisiana State University, Baton Rouge, LA 70803, USA Received 14 November 2000; received in revised form 12 February 2001; accepted 8 March 2001 Abstract Gastrointestinal nematode (GIN) parasitism is a major constraint to production of goats in the southeastern United States. The conventional method of control used by producers in this region is frequent use of anthelmintics during the warm season. Overuse of anthelmintics has led to an increase in the incidence of anthelmintic resistance in many parts of the world, but data on preva- lence of anthelmintic resistance in GIN of goats in the southeastern United States are very limited. To address this issue, anthelmintic efficacy was determined in goat herds at the Fort Valley State University, Agricultural Research Station (FVSU-ARS) and the University of Georgia, College of Veterinary Medicine (UGA-CVM) using fecal egg count reduction (FECR) tests and DrenchRite ® larval development assays (LDA). At FVSU-ARS, 2-year-old Spanish goat does were randomly allocated to one of nine different treatment groups (n = 10): albendazole (ABZ; 20 mg/kg body weight (BW)), fenbendazole (FBZ; 20 mg/kg BW), ivermectin (IVM; 0.4 mg/kg BW), doramectin (DRM; 0.4 mg/kg BW), moxidectin (MOX; 0.4 mg/kg BW), levamisole (LEV; 12 mg/kg BW), morantel tartrate (MOR; 10 mg/kg BW), a combination of IVM (0.4 mg/kg BW) and ABZ (20 mg/kg BW), and untreated controls. At UGA-CVM, goats were randomly allocated to one of five different treatment groups (n = 8): ABZ (20 mg/kg BW), IVM (0.4 mg/kg BW), MOX (0.4 mg/kg BW), LEV (12 mg/kg BW), and untreated controls. All drugs in both experiments were administered orally. Anthelmintic efficacy was calculated by comparing 14-day post-treatment FEC of treated and ∗ Corresponding author. Tel.: +1-478-825-6814; fax: +1-478-825-6376. E-mail address: terrillt@mail.fvsu.edu (T.H. Terrill). 0304-4017/01/$ – see front matter © 2001 Published by Elsevier Science B.V. PII:S0304-4017(01)00417-4