Novel Approaches to Control of Gastrointestinal Nematodes GINs in South American Camelids SACs

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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
Introduction 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.
Sericea lespedeza 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 groups
fecal egg count rose dramatically and remained
high throughout the trial, while the treatment
group
FAMACHA scoring 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 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) Summary 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