Novel methods for sustainable control of gastrointestinal nematodes in llamas and alpacas in the southeastern United States

Final Report for GS06-054

Project Type: Graduate Student
Funds awarded in 2006: $10,000.00
Projected End Date: 12/31/2009
Grant Recipient: Fort Valley State University
Region: Southern
State: Georgia
Graduate Student:
Major Professor:
Thomas Terrill
Fort Valley State University
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Project Information

Summary:

The graduate student completed several experiments to determine prevalence of anthelmintic resistance, validation of the FAMACHA system, and use of condensed tannin-containing forages to control gastrointestinal nematodes of llamas and alpacas in Georgia. Some anthelmintic resistance was found on all the farms tested, indicating a wide-spread problem. The FAMACHA system for identifying heavily parasitized animals worked well with llamas and alpacas and may be a useful diagnostic tool for these species. Sericea lespedeza (Lespedeza cuneata) reduced egg counts in llamas compared with bermudagrass (control diet), and may have potential as a natural anti-parasitic agent with South American camelids.

Introduction

The purpose of this project is to test novel, sustainable parasite control technologies in South American camelids (llamas and alpacas) in the southeastern United States (US). This industry (llama and alpaca production) is an emerging farming sector in the US. Based upon a survey of US camelid producers, infection with gastrointestinal nematodes is a significant concern with a majority of farmers, particularly in the Southeast (Unpublished data). Llamas and alpacas share similar parasites, particularly Haemonchus contortus, with sheep and goats, but much less information is currently available for camelid species. Anthelmintic resistance is reaching epidemic proportions in sheep and goats in the US, and this is likely an emerging problem with camelid species as well. Development and testing of non-chemical, environmentally-friendly control technologies is an important area of research to allow sustained growth of small ruminant and South American camelid industries in the US.

Several novel parasite control technologies have been successfully tested for use with sheep and goats in the US, but these techniques have not been tested with llamas and alpacas. One of these is the FAMACHA system of anemia detection, which was developed for use in sheep in South Africa. The FAMACHA card contains photos of the lower eyelid conjunctiva of sheep at various stages of anemia, from no anemia (red color) to severely anemic (white color). By comparing the eyelid color of an individual animal to the corresponding color on the FAMACHA card, farmers are able to assess the nematode infection level of that animal, allowing treatment of only the most affected animals in the flock or herd, which greatly slows the development of anthelmintic resistance. The FAMACHA system has been validated for use in sheep and goats in the southeastern US and the US Virgin Islands (Kaplan et al., 2004), but it has not been tested with llamas and alpacas. This system is only valid in regions where the primary infection is due to a blood-feeding parasite such as H. contortus, which is the primary parasite of camelid species in the Southeast. In the proposed work, the FAMACHA system will be validated on at least 15 alpaca and 15 llama farms in the southeastern US (Georgia, Alabama, South Carolina, and Tennessee).

Another non-chemical nematode control method that has shown promise is the use of anthelmintic plants. In a series of studies in which goats (Shaik et al., 2004; 2006) and sheep (Lange et al., 2006) were fed hay of the condensed tannin-containing legume sericea lespedeza (SL; Lespedeza cuneata), a consistent reducing effect on FEC and worm burdens and improvement in hematocrit values (PCV) has been reported. This plant is well-adapted to the southern US and grows well on acid, infertile soils. The anthelmintic potential of SL has not been tested with llamas and alpacas. In the proposed project, the anthelmintic effects of two types of hay will be evaluated with llamas and alpacas fed ad libitum on pasture during the fall, when hay is normally fed due to pasture shortage. The treatment forage will be SL hay, which will be compared with bermudagrass (Cynodon dactylon) hay as a non-tannin control.

Project Objectives:

1) Validate use of the FAMACHA system of anemia detection with llamas and alpacas on-farm.

2) Test the efficacy of sericea lespedeza hay against gastrointestinal nematode infection of llamas and alpacas on-farm.

3) Disseminate results from these studies in scientific and producer-oriented journals and as a published Master’s thesis.

Cooperators

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  • Rose-Ann Gillespie

Research

Materials and methods:

Surveys on anthelminitc use and production practices were mailed to llama and alpaca owners throughout the country as part of this project. The survey was mailed to 586 farms in 49 states, and 199 farms responded, representing 6080 animals from 39 states. In a second study,anthelmintic resistance was evaluated on 6 SAC farms (5 llama; 1 alpaca) throughout Georgia using either fecal egg count reduction (FECR) tests (3 farms), The DrenchRite® larval development assay (LDA; 6 farms), or both (3 farms). For the FECR tests, animals were randomly assigned to 1 of 5 treatment groups based on initial fecal egg count (FEC) and number of animals available (2 to 5 groups). Ivermectin (IVM; 0.3 mg/kg body weight (BW)) and a control group were tested on an alpaca farm, and fenbendazole (FBZ; 10 mg/kg BW; 2 farms), moxidectin (MOX; 0.2 mg/kg BW; 2 farms), and levamisole (LEV; 8 mg/kg BW; 1 farm) were added for llama farms. Anthelmintic efficacy was determined by comparing FEC of treatment and control animals 14 d post treatment, with resistance evaluated using the World Association for the Advancement of Veterinary Parasitology (WAAVP) guidelines. The DrenchRite® LDA assays were performed on feces pooled from treatment and control groups from each of the 6 farms. In another study, 189 SACs (n=131 llamas and n=58 alpacas), mostly females of assorted ages, from 6 farms in Central and North Georgia, were evaluated to validate the FAMACHA© system for use with these species. Each animal was given a 1-5 score scored using the laminated card associated with FAMACHA©, from 1, non-anemic, to 5, severely anemic. Blood and fecal samples were collected from each animal for determination of packed cell volume (PCV) and fecal egg count (FEC), respectively. Two FAMACHA© anemia thresholds were evaluated (>3 and >4), while PVC of <20 was considered anemic. In a final study, sericea lespedeza (Lespedeza cuneata) hay was compared with bermudagrass (Cynodon dactylon) hay for efficacy against GIN infection in with mature female llamas. Feces were collected from individual animals weekly for 6 weeks to determine fecal egg counts (FEC).

Research results and discussion:

Results of the survey indicated that growth trends for llama farming have stabilized (65%), while alpaca farming is increasing (73%) in the US, with the fastest growth in the Southeast. Feeding practices showed that animals are most often fed a combination of hay, pellets, and pasture (66%), and 66% of those farmers rotate their animals through different pastures. Most respondents (65%) consider their knowledge of parasite issues to be very good or better. Half (50%) of respondents indicated moderate parasite problems, and the 4% indicating severe problems were all in the southeastern US. Thirty-five percent use dewormers on a regular schedule, and in the Southeast, 5% deworm as often as every 3 weeks

In the anthelmintic resistance study, according to both the FECR and LDA test data, there was GIN resistance to ivermectin and fenbendazole on all the farms where these methods were used. There was moxidectin resistance on 1 llama farm using the FECR test, and low-level/suspected resistance to levamisole on 2 farms using the DrenchRite® system. These data demonstrate a serious emerging problem in the United States of llama and alpaca gastrointestinal nematodes resistant to drugs from all of the three major anthelmintic classes.

The correlations between FAMACHA©, PCV, and FEC were all highly significant (P < 0.001) for SAC data. Incidence of false negatives (animals with anemia not identified by the FAMACHA© system) was <2% for SACs whether FAMACHA© scores of >3 or >4 were considered anemic. False positives for the two FAMACHA© categories were 43.9 and 15.3%, respectively. These data show that FAMACHA© can be a valuable tool for anemia detection in llamas and alpacas in the US.

In the hay feeding trial, feeding sericea lespedeza (SL) hay to SACs somewhat reduced FEC compared with bermudagrass (BG) hay, but the differences were not significant (P > 0.05). The effect was greater in animals with lower infection levels. Feeding SL hay to SAC can assist in control of Haemonchus contortus infection in SACs, especially animals with low-level infection, delaying the need for use of chemical anthelmintics.

Participation Summary

Educational & Outreach Activities

Participation Summary:

Education/outreach description:

Refereed Journal Papers

Gillespie, R.M, L.H. Williamson, T.H. Terrill, and R.M. Kaplan. 2009. Efficacy of anthelmintics on South American camelid (llama and alpaca) farms in Georgia. Submitted to Veterinary Parasitology.

Theses

Gillespie, R.M., 2008. Evaluation of traditional and novel approaches to control of gastrointestinal nematodes in llamas and alpacas. Animal Science Master's Program, Fort Valley State University, Fort Valley, GA.

Project Outcomes

Project outcomes:

The survey work showed that llama and alpaca farming is a small, but growing industry in the US, and infection with gastrointestinal nematodes is one of the primary health concerns for South American camelid (SAC) producers.

There was a high prevalence of anthelmintic resistance on SAC farms in Georgia, and this may pose a major threat to this industry in the southeastern US. These results are impacting SAC farmers in the US by increasing awareness of this growing problem, indicated by the growing number of phone call and emails requesting information on the use of the FAMACHA system by llama and alpaca producers.

Economic Analysis

Economic analyses were not completed as part of this project, but as previous work with sheep and goats has shown, using the FAMACHA system to indentify and treat only the animals in the herd that are truely infected with gastrointestinal nematodes can reduce number of drug treatments by up to 80%.

Farmer Adoption

Indications of changes in llama and alpaca farming practices as a result of this work is currently anecdotal, based upon a growing number of telephone and email questions from producers concerning growing anthelmintic resistance problems in the South American camelid industry.

Recommendations:

Areas needing additional study

Additional data on use of the FAMACHA system to diagnose GIN infection in llamas and alpacas is needed to validate the use of this tool with South American camelid species.

Additional survey work would be very useful to determine impact of the completed project on farmers attitutdes on anthelmintic use with llamas and alpacas.

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.