Haemonchus contortus (Barber Pole Worm) Infestation in
Goats
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| Maria Lenira Leite-Browning,
DVM, Extension Animal Scientist, Alabama A&M University
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Gastrointestinal nematodes,
commonly known as worms, present the greatest danger to the
goat industry in the Southeastern region of the United States.
Haemonchus contortus, commonly referred to as the barber pole
worm, is a clinical problem for goats. Anemia, low packed
cell volume (PCV), diarrhea, dehydration, peripheral, and
internal fluid accumulation are common signs of barber pole
worm infestation. Infested goats have lower growth rates,
markedly reduced reproductive performance, and have higher
rates of illness and death. Consequently, H. contortus may
account for greatly reduced profits in a goat operation. |
| In the Southeast region, there are a number of
factors that contribute to barber pole worm infestation in goats: |
- Environment with high temperatures, humidity, and rainfall
- Genetic make-up of goats makes them highly susceptible
- Resistance to anthelmintics as a result of excessive usage
- Frequent anthelmintic treatments per year without a positive
fecal sample exam
- Many goat producers overstock their pastures and maintain
as many as 40 goats per acre
- Few anthelmintics drugs are approved by the Food and Drug
Administration for goat use.
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| About Barber Pole Worms |
Haemonchus contortus is cylindrically shaped, tapered at both
ends, and has a complete digestive system. This worm is a worldwide
threat, but is more prevalent in sub-temperate and temperate
regions under warm and wet conditions, such as in the Southeastern
United States. |
| Morphology |
Adults (20-30 mm); Eggs are thin-shelled, 24 cell
Adult H. contortus live in the abomasum (true stomach) of goats. |
|
Adult H. contortus recovered after
necropsy. |
| Life Cycle |
Goats are born without H.
contortus; however, they become infested with the worm when
they start grazing. The L3, or infecting larvae, are eaten
by the goats during grazing. The L3 larvae then burrow into
the internal layer of the goat's abomasums (true stomach)
where they develop to a L4, or preadult larvae. The L4
molts into L5, the adult form. |
Adult male and female worms
live in the abomasum of goats, where they feed on blood. The
worms mate and produce eggs. Adult females deposit from 5,000
to 10,000 eggs per day, which are passed through goat feces
to the pasture. Eggs are hatched either in soil or water.
When the soil is warm and moist, eggs will hatch into L1 larvae
(first stage juveniles). The L1 larvae then develop through
stages L2 and L3. Large numbers of juvenile parasite worm
(L3) may accumulate on heavily grazed pastures. |
| Damage Caused by Barber Pole Worm |
After a goat has ingested
L3 larvae, the worm will burrow into the mucosal (internal
layer) of the stomach, nourishing on the red blood cells of
the goats, which can be life-threatening to the goat. An infected
goat can bleed to death within hours. |
|
Stomach after necropsy.
[Diffused hemorrhagic areas of the mucosa (internal layer)
of the stomach] |
| Signs of the barber pole worm infestation
in goats: |
- Diarrhea
- Dehydration
- Unthrift appearance, rough hair coat, depresssed, low
energy, lethargic, and uncoordinated
- Significantly reduced growth and reproductive performance
- Fluid accumulation in sub-mandibular tissues (bottle jaw),
abdomen, thoracic cavity, and gut wall
- Blood loss, white mucous membranes, anemia/PCV
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Signs of peripheral and submandibular
(bottle jaw) edema |
Extreme dehydration, near
death |
Note:
Larva is a juvenile form, the newly hatched, or earliest stage
worm that undergoes metamorphosis, differing markedly in form
and appearance from the adult. Anthel-mintics are widely used
to battle worms and worm eggs. |
Blood loss, anemia, white musous membranes |
| Controlling Barber Pole Worm |
| Scientists have been researching ways to manage
this parasitic worm and minimize cost production in herds. Management
practices must be based upon breaking or interrupting the life
cycle of the worm by: |
Use of chemical anthelmintics commercially available
Improved herd and pasture management practices
Use of plants with anthelmintic properties |
| Use of Commercial Anthelmintics |
Anthelmintics (chemicals/drugs)
are widely used to battle barber pole worms. However, only
two anthelmin-tics are approved by the Food and Drug Administration
(FDA) to treat goats: Morantel tartrate and Fenbendazole.
Producers have reported that the drugs have shown little effectiveness
in the control of the barber pole parasite in goat herds because
of the worm's resistance. |
| Use of others anthelmintics is called extra-label
use because they are not approved by the FDA for use on goats
unless used under veterinarian guidance. |
| Table 1: Anthelmintics (Chemicals or drugs for
deworming) with a direct effect on the worm or worm eggs |
| Anthelmintics
(Dewormer) |
Brand Name |
FDA Approval |
Dosage |
Route |
| Benzimidazoles Fenbendazole |
Panacur/ Safeguard |
App'd |
9.0mg/lb |
Oral |
| Cholinergic Agonist Morantel tartrate |
Rumatel |
App'd |
4.5mg/lb |
Oral |
|
| Note: Consult your veterinarian as
part of your parasite control program to get information about
the appropriate use, dose, route, duration, possible adverse
effects, and withdrawal periods for various extra-label anthelmintics
before administration in your herd. |
| Improved Herd, Pasture and Management
Practices |
| Here are some ways to control barber pole worms: |
| Feeding Practices |
-
Keep stocking rates low.
-
Provide clean water and minerals.
-
Use gravel or concrete in the feedlot
area to break the worm life cycle and to prevent re-infestation.
-
Provide high-quality hay for goats
raised in areas where forage is not available year-round
or when the pasture conditions are poor. Hay should be
kept off of the ground to avoid contamination by feces.
|
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Dry lot to interrupt worm life cycle. |
| Pasture Maintenance |
- Incorporate browse plant species when possible. Goats
love to browse and prefer shrubs and forages to grass.
If goats consume forages at least 6 inches tall, infestation
from barber pole worms is reduced.
- Try a mixed species grazing program using cattle and
goats.
- When possible, use the pasture for hay cutting after
grazing. This will help to break the worm life cycle and
prevent re-infestation. Direct sunlight during the summer
months or during freezes in the winter will also help
decrease the population of larvae that remain in the soil.
- When possible, alternate the pasture with a short cycle
crop, such as culture alfalfa. This management practice
will help to break the worm's life cycle, and decrease
larvae population in the pasture and prevent re-infestation.
- Use clean feeders and continue to practice good hygiene
in the pens and pasture.
|
| |
Goats are browsers, introduce shrubs and forbes
in your pasture |
| Doe Treatment |
- Provide good nutritional management. Well-nourished
animals are better able to respond to H. contortus infestation.
Does with good nutrition at late pregnancy have an increased
immune response to parasites.
- Deworm the doe soon after she has kidded. The pregnancy
hormone progesterone and the lactate hormone prolactin
have been shown to reduce the ability of does to fight
worm infestation. Progesterone suppresses the doe's immune
system. Does that are lactating and raising kids are more
susceptible to worms. Monitor the herd closely from kidding
to weaning.
- Goat genetics are an important component that will determine
an animal's ability to resist H. contortus infestation.
Resistance can be measured by fecal egg counts (FEC).
The resistance to worm infestation is heritable. The doe's
ability to withstand infestation is defined as resilience
and is measured by blood hematocrit or packed cell volume
(PCV). Resilience is less heritable than resistance.
|
| FAMACHA System as a Management Tool to
Control Barber Pole Worms in Goats |
The FAMACHA system was developed
by South African scientists and veterinarians. It is a low-cost
tool that can greatly influence management practices in goats.
The FAMACHA system monitors clinical anemia (reduction of
red blood cells, packed cell volume) by examining the color
of the goat's lower eyelids and comparing it to a color-coded
chart. Variation in eyelid color from pale to red indicates
the degree of anemia. Based on this chart, only goats with
anemia should be treated. This practice will prevent the overuse
of anthelmintics and consequently minimize chances of parasite
resistance to anthelmintics. The test has an effectiveness
of 90 percent compared to the 20-30 percent effectiveness
of overused anthelmintics. |
Goat producers should check
10 percent of the total animals in the herd as frequently
as every other week using the FAMACHA chart. A fecal exam
should accompany FAMACHA examination. |
FAMACHA also provides producers
with a tool for genetic selection. Using FAMACHA, producers
can identify animals that are more susceptible to hosting
the worm and can cull these goats from the herd. In turn,
producers will be able to identify animals with high resistance
and resilience, which seem to be inherited traits in goats. |
| Use of Plants with Anthelmintic Properties |
Researchers are exploring
the use of plants to control barber pole worm. Forages, such
as clover, vetches, chicory, and sericea lespedeza, contain
condensed tannins. Condensed tannins reduce the number of
stomach worms and egg production. Feeding sericea lespedeza
hay to goats can reduce fecal eggs counts by 80 percent and
create a higher packed cell volume. |
| References |
Browning, R. Jr., et al.
(August 2006). Evaluation of three meat goat breeds for doe
fitness and reproductive performance in the southeastern United
States. IN 8th World Congress on Genetics Applied to Livestock
Production, Belo Horizonte, MG, Brazil.
Fleming, S. A., et al. (2006). Consensus
Statement on: Anthelmintic resistance of gastrointestinal
parasites in small ruminants. Journal of Veterinary Internal
Medicine, 20, 435444.
Kaplan, R. M., et al. (2004). Validation
of the FAMACHA© eye color chart for detecting clinical
anemia in sheep and goats on farms in the southern United
States. Veterinary Parasitology, 123, 105-120.
Shaik, S. A., et al. (2006). Sericea lespedeza
hay as a natural deworming agent against gastrointestinal
nematode infection in goats. (2006). Veterinary Parasitology,
139 (1-3), 150-7.
Van Wyk, Jan A. & Bath, Gareth F. (2002).
The FAMACHA© system for managing haemonchosis in sheep
and goats by clinically identifying individual animals for
treatment. Veterinary Research, 33, 509-529.
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