Novel Approaches to Control of Gastrointestinal Nematodes (GINs) in South American Camelids (SACs). Gillespie, R.M. RVT, BS*, Terrill. T.H., PhD*, Williamson, L.H., DVM#, Kaplan, R.M, DVM, PhD#. Introduction
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Novel Approaches to Control of Gastrointestinal Nematodes (GINs) in South American Camelids (SACs)
Gillespie, R.M. RVT, BS*, Terrill. T.H., PhD*, Williamson, L.H., DVM#, Kaplan, R.M, DVM, PhD#
SAC farming is a growing sector of U.S. agriculture. Unfortunately, SACs suffer from the same GINs as other small ruminants, especially Haemonchus contortus. These GINs are becoming increasingly resistant to chemical anthelmintics for other species, little information is available on GIN resistance in SACs. This study was to 1) determine level of resistance to chemical anthelmintics in SACs. 2) Validate FAMACHA scoring with SACs, and 3) determine whether or not sericea lespedeza (Lespedeza cuneata) acts as a natural anthelmintic in SACs.
Feeding high condensed tannin forages have been reported to reduce GIN load in small ruminants. Sericea lespedeza is a high tannin forage that grows well on acid, infertile soils and produces high quality hay. Effectiveness of this forage to control GIN infection has been tested with sheep and goats, but not with SACs. Seventeen female llamas were fed supplement and either bermudagrass (Cynodon dactylon) or sericea lespedeza hay. Fecal samples were collected weekly over a 6-week trial to determine fecal egg counts. Control group’s fecal egg count rose dramatically and remained high throughout the trial, while the treatment group
FAMACHA scoring correlates the density of color of the eye conjunctiva to the level of anemia in the animal, and thus parasitic load. This allows a farmer to treat only the most affected animals, which leaves some GINs untreated and retards the development of resistance to anthelmintics. To test this a blood sample and a FAMACHA score (1-5, 1 being healthiest) were obtained from 300+ SACs. The blood samples were analyzed for packed cell volume. These numbers were correlated to the FAMACHA score. Differences in peripheral circulation in SACs may affect FAMACHA scores in these animals, but definitive conclusions on the usefulness of this tool for SACs will require additional data to be collected and analyzed.
Anthelmintic resistance was tested on 4 llama and 1 alpaca farms in Georgia. Parasite load was determined by number of ova contained in feces. Subjects were divided into treatment and control groups. Treatment groups were given various anthelmintics, with ova counted pre and 14 days post treatment. Haemonchus were resistant to both Fenbendozole and Ivermectin, but were susceptible to Moxidectin. In vitro Larval Development Assays showed at least some resistance to Ivermectin and Benzimidazole classes on all farms with some resistance to Levamisole and susceptibility to Moxidectin.
fecal egg count count remained consistently lower than the control group (average of 63% lower 4 out of 6 weeks)
1) Anthelmintic resistance has spread to the SAC industry and the problem in the southeast is more serious than expected.
2) Use of FAMACHA scoring to determine heavily parasitized llamas and alpacas would allow reduced use of anthelmintics with these species, but further testing is needed to validate this procedure for SACs
3) Sericea Lespedeza has potential as a natural alternative to chemical anthelmintics for SACs.
Funded by Southern SARE
* Fort Valley State University, Fort Valley, GA, #University of Georgia, Athens, GA