Controlling Internal Parasites
in Small Ruminants
Sheep & Goat Toolbox
Small ruminant overview
Goats
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Prefer to browse
Selective eaters
Like to roam
Can handle some
toxins other livestock
can’t
• Like variety
Sheep
• Prefer to graze
close to the
ground
• Like to roam
• Enjoy many
weeds
Introduction to parasites
• Biggest concern for small
ruminant producers
• Costly
– Treatment costs
– Reduced animal performance
– Death
• Parasites have developed
resistance to dewormers
• Parasites can be managed
We cause problems
• We force them to eat close to the
ground
• We crowd them
• We cause parasite resistance
– Deworming too often and incorrectly
• We create environments where
parasites thrive
• We don’t keep them in good
enough condition
• We “baby” our animals
– keep animals that we should cull
The problem: parasites
Photos courtesy of Dr. Jean Marie Luginbuhl, North Carolina State University
Primary parasites
• Barberpole worm
– Haemonchus contortus
• Brown stomach worm
– Telodorsagia (Ostertagia)
circumcincta
Picture from www.sheepandgoat.com
• Bankrupt worm
– Trichostrongylus
colubriformis
• Coccidia
– Eimera sp.
Diagram from
www.sheepandgoat.com
Parasite life cycle
• Parasite larvae
ingested
• Adults make residence
in the body
• Adults lay eggs
• Eggs passed in feces
• Eggs hatch and larvae
crawl up blades of
grass
• Animals ingest larvae
(repeat cycle)
Diagram from
www.sheepandgoat.com
Parasitism
• Practically inevitable
• Should be managed so
that parasitism is not
evident
• Young animals most
affected
• Does/ewes affected last
month of pregnancy &
around kidding/lambing
Signs of parasitism
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Loss of condition
Rough hair coat
Bottle jaw
Low energy
Signs of parasitism (cont.)
• Pale mucous
membranes
– Indicates anemia
• Scours, diarrhea
• Death
We cannot rely on drugs alone!
• Parasites are becoming resistant to drugs
– Particularly sheep & goats
• Parasites are already becoming resistant to the
newest anthelmintic drugs
• We are running out of drugs!
• Anthelmintics should not be overused
– Increases resistance
• Other methods must be used in conjunction with
anthelmintics
Causes of resistance
• Frequent deworming
– No dewormer is 100% effective, 100% of the
time
– Frequent deworming increases the rate
resistance develops
• Deworming all animals,
regardless of need
– Increases rate of resistance
– Costs more $$$$$
• Under dosing
– Leaves more of the strong worms
• Deworming and moving to a clean
pasture
What do we do?
• Pasture management
– Sanitation
– Avoid over-grazing
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Animal management
Animal selection
FAMACHA©
Smart Drenching
Other techniques
Pasture management
• Should be the primary
technique
• Monitor Forage Height
– Research indicates that most
larvae can only travel about 2
inches off the ground
– Grazing close to the ground
increases parasite ingestion
Pictures from www.sheepandgoat.com
Pasture management
• Stocking Rate
• Overstocking causes:
– More worm deposits
– Animals forced to graze close to
manure
• Multi-species Grazing
– Small ruminants, cows, and horses
do not share the same parasites
• Haying
– Removes & exposes larvae to the
sun
Animal management
• Immune System
– Healthier animals have
fewer problems
– Provide good nutrition
• Select resistant animals
– Select a resistant buck/ram
– Select resistant breeds
Picture from: ansi.okstate.edu
Provided by Dr. An Peischel
• Goats: Spanish, Myotonic, Kiko,
not Boer
• Sheep: Hair Sheep, Florida Native
• Cull
– Animals needing more treatment
– Animals depositing a lot of eggs (FEC)
General management
• Sanitation
– Keep feeders and water
free of feces
– Keep areas where
animals congregate as
clean as possible
• Carefully chose, isolate,
and de-worm new
animals
FAMACHA©
Classifies animals based on level of
anemia
1-5 scale
• 1-not anemic
• 5-anemic
Treat 4’s and
5’s
Sometimes 3’s
Photo from www.sheepandgoat.com
FAMACHA©
• Must be trained by a
veterinarian
• Keep records
• Cull animals
repeatedly treated
• Treat less, save
money!
Smart Drenching
• Find out which dewormers work
– Talk to your local veterinarian
• Weigh animals prior to deworming
– Don’t under-dose
• Deliver dewormer over
the tongue, in the back of
the throat
• Withhold feed 12 to 24
hours prior
• De-worm only animals
that need it!
Photo from http://bedford.extension.psu.edu
Other techniques: copper wire
• Copper oxide wire particles
(COWP) have been proven to be
an effective method of controlling
H. contortus (barber pole worms)
in sheep & goats
• COWP can be an effective
component of a holistic parasite
management strategy.
• Should not be the only method of
parasite management
http://animetal.com.tr
How to use COWP
• Purchase copper boluses
– Copasure©, available in 12.5 g and 25 g boluses
• Obtain smaller gel capsules
– Available at your local pharmacy or health food store, also
available from veterinary supply at times.
• Repackage cattle bolus into smaller gel capsule
to make 0.5g dose
– Size 1 gelatin capsules filled1/3 full
– Size 3 capsules filled 3/4 full
• Administer bolus with a pill gun designed for
pets or wooden dowel with PVC pipe
How it works
Copper oxide wire particles
• Animals should receive no more than
• Four (if 0.5 or 1 g is used) or
• Two (if 2 or 4 g is used)
Per worm season
• Effective in reducing abomasal
(H. contortus) worms only and not
intestinal worms.
• COWP should not be the only method used
for controlling internal parasites.
Other techniques: condensed
tannins
• Effects of tannins vary depending on type,
concentration, and the animal consuming the
tannins.
• Potential positive effects:
– Increase in by-pass protein
– Reduction in bloating, increased milk production
– Reduction in internal parasite numbers, egg output, &
hatchability.
• Potential negative effects:
– Reduced intake and reduced digestibility, leading to a
decline in animal productivity.
– Negative effects are seen more often when CT
concentration is high (above 55 g CT/kg DM in the forage)
Other techniques: condensed
tannins
Condensed tannin (CT) content in different forage
species.*
(Adapted from Min and Hart, 2003 and Min et al., 2005).
Forage
CT, g/kg of DM
%DM
Birdsfoot trefoil
48
4.8
Big trefoil
77
7.7
Sanfoin
29
2.9
51-84
5.1-8.4
0.5
.05
Sericea lespedeza
46-152
4.6-15.2
Perennial ryegrass
1.8
0.18
Chicory
3.1
0.31
Crabgrass/tall fescue mixture
3.2
0.32
Sulla
Lucerne (alfalfa)
*The standard used for analysis will affect the results. For these studies, a Quebracho standard was used.
Condensed tannins: Sericea
lespedeza
• High-tannin forage
• Scientifically proven to reduce
parasite loads in sheep and
goats.
• Research has shown that
Sericea is effective against
internal parasites when grazed
or when fed in dried forms, such
as hay or pellets.
Other techniques
• Garlic
• Nematode-trapping
Fungus
– Fungus traps parasite larva
in the feces
– Not commercially available
yet
• Vaccines
– Not available yet
Conclusion
• Parasites are the biggest
problem for sheep and goat
producers
• No technique is 100% effective
• Several techniques should
be used
• Select for resistant animals
• Do not over-treat (causes
resistance!)
http://www.flickr.com/photos/mikeboehmer/147
0921528/in/set-72157602227248322/
For more information
• See ATTRA publications at www.attra.ncat.org
• Managing Internal Parasites
• “Tools for Managing” series:
• Copper Wire
• Sericea Lespedeza
• Animal Selection
• Pasture Management
• American Consortium for Small Ruminant
Parasite Control at www.acsrpc.org
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