1. Integrated Parasite Management
(IPM) in Small Ruminants
Sheep & Goat Specialist
University of Maryland Extension
SMALL RUMINANT PROGRAM
2. AMERICAN CONSORTIUM
FOR SMALL RUMINANT
PARASITE CONTROL (ACSRPC)
www.acsrpc.org – www.wormx.info
3. Internal Parasites
#1 health problem in sheep and goats in warm, moist climates
Sheep and especially goats are the
most susceptible livestock to internal
Close grazing, especially by sheep
Graze close to fecal pellets
Slow-to-develop immunity, esp. goats.
Temporary loss of immunity at parturition
Affected by one of deadliest parasites
We can no longer rely on
anthelmintic treatments alone to
control parasites; a more integrated
approach is necessary.
Few anthelmintics are FDA-approved for
sheep; even fewer for goats.
Worms have developed resistance to all
anthelmintics and anthelmintic classes.
Can’t count on many new drugs.
anthelmintic = dewormer = drench = anti-parasitic drug
4. Haemonchus contortus
The Barber Pole Worm
A blood-sucking parasite
(roundworm) that pierces the
mucosa of the abomasum
(ruminant “stomach”) and
causes blood plasma and
protein loss to the sheep,
goat, or camelid.
I want your
0.05 ml blood per day
5. Barber Pole Worm
Anemia: pale mucous
NOT diarrhea (scours)
 Sudden DEATH
Difficult to control
Short, direct life cycle
Prolific egg producer
Can go into “hypobiotic”
(arrested) state during
conditions (e.g. winter)
Can survive on pasture
for a long time.
→ Adaptable to environment
Weight loss, unthrifty
Rough hair coat
6. Other gastro-intestinal (round)
worms from strongyle family
Direct life cycles
Burrow into the wall of the
abomasum or intestines.
→ Usually secondary in importance.
→ Usually have an additive effect in
mixed parasitic infections.
Symptoms: scouring, weight loss,
rough hair coat, ill thrift, poor
7. Fecal egg counts - Larvae ID
2009 Western Maryland Pasture-Based Meat Goat Performance Test
Indirect life cycle
 Worms live in the small intestines.
 Eggs pass out through feces (in segments)
 The egg is eaten by a pasture mite.
 The egg hatches.
 The mite is eaten by the sheep or goat.
 It is the only parasite we can see in the
feces – that’s why we don’t like it!
Light/moderate loads of tapeworms tend
not to be a problem, but heavy infestations
could cause an intestinal blockage or affect
Tapeworms are generally considered to be
Treat with albendazole or praziquantel.
→ Deworming for tapeworms has not been
shown to increase performance in lambs.
Can have indirect or direct life
Transmitted in feces.
Difficult to see in fecal sample
(larvae) – different procedure
Severe infestations can result
in coughing, fluid on lungs,
Difficult to diagnose in live
animal; diagnosis is usually
Most drugs which kill stomach
worms kill lung worms.
10. Liver flukes
Generally not considered to be a
problem in Mid-Atlantic area.
Gulf states and Pacific Northwest.
Require open water and aquatic
snails (wet conditions) as
Can kill adult liver flukes with
Albendazole (Valbazen®) or
Ivomec® Plus (Plus=clorsulon).
Eimeria spp. (host-specific)
Normal inhabitant of ruminant’s
More than 10 species affect sheep
Not all are pathogenic or equally
Single-cell protozoa that damage
the lining of the small intestines,
affecting absorption of nutrients.
Causes diarrhea that may be
smeared with blood and/or
Signs of disease occur ~17 days
after infection (ingestion of
Damage can be permanent!
 Prevent with good sanitation and
Fecal samples are of limited
value in diagnosing coccidiosis.
Eimeria spp. (host-specific)
Can use additives in feed,
mineral, or water to help
prevent clinical disease in
groups of animals:
Amprolium (Corid®) in
Sericea lespedeza may help
to control coccidia.
Treat (individual animals)
with Amprolium or sulfa
drugs (requires Rx).
1FDA-approved for sheep
2FDA-approved for goats
3TOXIC to EQUINES!
13. Meningeal worm (deer, brain worm)
Parasite of the White Tail Deer
Small ruminants are abnormal hosts
for the parasites.
sheep, goats, llama, alpaca, horse
Parasite has indirect life cycle
Terrestrial snails and slugs are needed
as intermediate host
Once ingested, larva travel from
intestinal tract to spinal cord to brain,
causing progressively worse
symptoms . . .
Hind quarter weakness
Animals often maintain appetite
Cannot easily diagnose in
a living sheep/goat
(necropsy or spinal fluid)
No proven treatment
High doses of anthelmintics
Some recover on their own.
Some do not respond to Tx.
Cannot repair damaged tissue.
Restrict access to certain
areas of pasture, certain times
Control deer population
Control snail/slug population
Monthly deworming with
Fencing to exclude deer
is not usually practical.
15. How do you know what kind of
worms your sheep or goats have?
16. Parasite identification
1) Fecal flotation or egg count
 Can differentiate between strongyle
(stomach), tapeworm, and coccidia
 Can’t differentiate between most
strongyle (stomach) worm eggs.
eggs (except Nematodirus)
 Meningeal worm does not pass eggs
• Public lab
• Diagnostic lab
• Private lab
• Veterinarian Eimeria spp.
17. Stomach worm identification
2) Fecal coproculture / larvae ID
Differentiate between strongyle
(stomach) worms (H. contortus,
Teladorsagia, and trichostrongyles)
• University of Georgia
(Dr. Ray Kaplan’s lab)
 Can take test one step further to determine
anthelmintic resistance -- larval development
assay (LDA) or DrenchRite® test.
3) Lectin-staining test (new)
Determine percent of Haemonchus
contortus eggs in sample.
• Oregon State University
• University of Georgia
18. How do sheep and goats
get infected with parasites?
sheep/goats + grazing (pasture) = worm infection
L3’s infective larvae ingested  L4’s and adults suck blood
19. Life Cycle of Stomach Worms
Eggs require warmth (60°F) and humidity to hatch to first stage larvae.
Worm problems vary by
location, farm, year, and season.
20. S O NA J AM J DM JFJ
When Are Larva On Pasture A Problem?
Why & How Do Seasonal Increases Occur?
( If No Treatment)
21. JMF AM J A S O N D J
Fecal Egg Counts
(What happens in ewes and lambs)
22. Population Demographics of
How long before
3 weeks1 2 weeks1
When are the
highest levels of
5-9 weeks 3-9 weeks
How long until low
levels of pasture
3 months 3 months
1 Earlier if high temperatures coincided with rain.
Patterns of Ostertagia circumcincta, Trichostrongylus spp. and Cooperia curticei were basically
similar to H. contortis. Strongyloides papillosus larvae emerge within 2 weeks on pasture and
survival is short. Nematodirus larvae took a lot longer to emerge on pasture than the other
Utrecht University (Netherlands) 1999-2003
Research conclusion: Only a small number of farms can use evasive grazing
as the only method of parasite control. For most farms, evasive grazing
needs to be combined with other pasture control strategies.
23. Integrated Parasite
Goal is not to create parasite-free animals. It is
normal for sheep and goats to have parasites. Goal
is to prevent clinical disease and production losses.
24. Consider host resistance
Weaned lambs and kids
Orphan lambs and kids
High producing females
Late -born lambs and kids
25. Parasite control begins with good
management and common sense
Use of feeders which prevent
wastage and contamination.
Clean water, free from fecal
matter and other debris.
Avoid overstocking pens and
Isolate and deworm new
additions to the farm.
The primary cause of internal
parasitism is overstocking.
26. JMF AM J A S O N D
Market by July 1
27. JMF AM J A S O N D
Fall lambing and kidding
28. Use of “clean or safe” pastures
A pasture that has been renovated
A pasture that has not been grazed
by sheep or goats for the past 6 to 12
A pasture that has been grazed by
horses and/or cattle for the past 6 to
A pasture in which a hay or silage
crop has been removed.
A pasture that has been rotated with
Pasture that has been burned
Severely overgrazed pasture????
Cleaner, safer pastures are a more realistic goal for most producers.
29. Graze multiple species
Sheep and goats share the same
internal parasites, but they are
different from the parasites that
affect cattle and horses.
Except barber pole worm in young calves.
Producers who graze multiple
species of livestock report fewer
Cattle and horses “vacuum”
sheep/goat pastures of infective
There are other benefits to mixed
species grazing, such as
complimentary grazing habits.
30. Pasture Rest and Rotation
Pasture rotation is a recommended
strategy for controlling internal
parasites because it allows the use
of safe or safer pastures.
BUT, intensive rotational grazing
may not help to reduce parasitism
unless rest periods are long
Due to increased stocking rates,
management intensive grazing
could increase internal parasite
problems in sheep and goats.
In a rotational grazing system,
ideally, sheep/goats should not be
returned to the same pasture for 2
to 3 months.
31. Alternative forages
Livestock that browse have
fewer parasite problems.
Livestock grazing tall-
growing forages will have
less parasite problems.
80% of parasites live in the
first 2 inches of the
Grazing tanniferous forages
may reduce the effects of
No worm larvae
32. Chicory, birdsfoot trefoil, and
Sericea Lespedeza have all
been shown to reduce fecal
egg counts and/or inhibit
33. Sericea lespedeza
Lespedeza cuneata (high tannin variety)
Warm season legume that
grows in acidic soils with low
fertility and tolerates drought
Fed as . . .
Loose or ground hay
Pelleted supplement (leaf meal)
Goats readily eat.
Sheep will eat.
For control of barber pole worm
May also control coccidiosisImages from acsrpc.org
34. Nutritional Management
Animals on a high plane of
nutrition and in better body
condition are better able to
withstand worm burdens.
Nutrition in early pregnancy (fat
stores) can affect the immune
response to internal parasites.
Sheep receiving higher levels of
protein prior to lambing have
lower fecal egg counts.
Supplementing grazing lambs with
protein has been shown to reduce
fecal egg counts.
Nutritional supplementation is most likely to be beneficial when pregnant females and young animals
are below optimal body condition at a time when pasture quality and/or quantity is limited.
35. “Zero” grazing
bedded pens, dry lot with no green vegetation, slatted floors
Sheep/goats raised in
confinement or dry lot
(zero grazing) tend to
have fewer worm
Sheep/goats put in
confinement or dry lot do
not usually get re-
infected with worms.
Coccidiosis could still be
a problem, if
are not taken.
Avg. Fecal egg counts (FEC, epg)
36. Genetics and worms
Two important traits: resistance and resilience
Ability of host to limit infection
Quantified by fecal egg counts (FEC)
FECs estimate number of worms in gut.
Ability of host to withstand challenge
and/or infection, and thus maintain
health and productivity.
Quantified by blood hematocrit or
packed cell volume (PCV)
FAMACHA© scores estimate PCV
Parasite traits are moderately heritable - 20-40 percent
37. “Resistant” Breeds
Some sheep and goat breeds are more resistant and resilient to worms.
Gulf Coast, Florida, Louisiana
There is less data comparing
parasite resistance in goat breeds.
38. “Resistant” animals
There is as much difference within breeds as between breeds.
The 80-20 rule (70:30)
Approximately 20 percent of
the flock sheds most (~80
percent) of the parasite eggs.
Focusing deworming on
susceptible animals will
significantly reduce pasture
animals will increase flock
resistance and reduce
Only resistant males should
be used for breeding!
39. Distribution of FECs in a herd
EPG, August 29, 2009
40. Heritability of FEC and PCV
Ewes 0.31 0.15
Lambs 0.10 0.39
2004, Vanimisetti, Andrew, Zazac, Notter
is possible and will
not adversely affect
growth of lambs and
fertility of ewes.
41. Comparison of Genetic and
Non-genetic Control Strategies
Strategy Reduction in FEC’s
Genetic Selection 69%
Protein supplementation 35%
Strategic deworming 28%
Experimental vaccine 0%
•Monitor sheep, run in the plots after the end of the experiment had
lower FEC’s when run in the plots previously grazed by
supplemented sheep (35%) or selected sheep (46%).
•The largest and most persistent effect on FEC’s and worm
contamination of pasture was achieved by genetic selection.
A valuable, limited resource that
must be managed properly.
43. Three drug families
Drugs kill parasites by starving them or paralyzing them.
Chemical name ends in '..dazole
3) Macrolytic lactones
First class of modern
Most broad spectrum:
adult and L4 larvae
Wide margin of safety
→ High level of resistance
FDA-approved for sheep
(7 day slaughter withdrawal).
Labeled for control of liver flukes in non-
lactating goats (7 day slaughter withdrawal)
For control of …
1. Adult and 4th stage larvae of GI worms
2. Varying levels of activity against hypobiotic
3. Adult and larval forms of lungworms
4. Heads and segments of tapeworms
5. Adult liver flukes
Safe, but use restricted during pregnancy
(1st 30 days).
Widespread resistance across industry.
Fast animals to improve efficacy.
SafeGuard®, Panacur® drench
FDA-approved for goats (6 day
Labeled dosage should be doubled
For control of adult GI worms and
Widespread resistance across
Fast animals to improve efficacy.
Double dosage will kill heads and
segments of tapeworms.
One of the preferred drugs for
treating meningeal worm.
Prohibit®, Levasole®, Tramisol® drench or oblets
FDA-approved for sheep
(3 days slaughter withdrawal)
For control of
Adult and L4 larvae stages of GI
Hypobiotic larvae (?)
Adult and larvae forms of lungworm
→ Probably the most effective
Lowest margin of safety
Treat based on accurate weights
Goats – 1.5x sheep dose
Best to feed goats individually.
FDA-approved for all classes of
For control of mature worms
30-day slaughter withdrawal.
Not much is known about its
efficacy or resistance.
(Macrolytic lactones, ML’s)
Adult and L4 larvae GI worms
Adults and larvae stages of
External parasites (biting)
Wide margin of safety
51. Avermectins: Ivermectin
Introduced in the 1980’s.
Drug of choice for meningeal
For control of . . .
Adult and L4 larvae GI worms
Adult and larvae lungworms
Larval stages of nosebot
11-day slaughter withdrawal
High levels of resistance in
Fast animals to improve efficacy
Newest drug (1997).
For control of mature and L4
larval stages of GI worms.
7-day slaughter withdrawal
Similar to ivermectin, but
disrupts different chemical
May kill ivermectin-resistant
Due to similarity to Ivermectin,
resistance will develop rapidly if
it is overused.
53. Extra-label Drug Use
(SafeGuard®) and Morantel
(Rumatel®) are FDA-approved
for goats – and only at dosages
listed on label.
Ivomec® drench, Cydectin
drench, and Levamisole
(drench and bolus) are FDA-
approved for sheep.
Use of a product that is
different from its label
constitutes extra-label drug
use and requires a veterinary
prescription and valid
54. Withdrawal for extra-label drugs
Use longer withdrawals
for extra-label drugs.
Meat withdrawal for
Cydectin® drench is 23
days when administered to
goats at double the dosage
as compared to 7 days for
sheep. (source: farad.org)
Meat withdrawal is 120-130
days for Cydectin® 1%
administered to goats as
compared to 21 days for
cattle. (source: farad.org)
Keep records of
55. The future of parasite control
1) New anthelmintics
2) Natural “dewormers”
• “Paravac” consortium
4) Gene-marker assisted
56. Zolvix® (monepantel)
New drug class
Amino-acetonitrile derivative (ADD)
Unique mode of action
First new anthelmintic class in 25 years
Kills worms that are resistant to other
Currently only registered for use in New Zealand,
Great Britain, and Uruguay.
Testing is complete in US; waiting for company to
Will it be approved for goats?
Overuse will cause worms to develop resistance
to it just like the other drugs.
57. Natural “anthelmintics”
Natural “anthelmintics” have
not been shown to be effective
at treating parasitism, but
perhaps their use will reduce
the number of animals that
58. Copper oxide wire particles (COWP)
Made from Copasure®, a
copper bolus marketed for
copper deficiency in cattle.
Can repackage into doses
suitable for sheep and goats.
Also commercially available in 2
and 4 g doses.
In research trials, the minimum
dose that has demonstrated
control is 0.5 g, but as much as
2-4 g may be necessary.
Use FAMACHA© system to
determine who gets a copper
For barber pole worm only.
59. Anthelmintic resistance
How to measure
Fecal Egg Count Reduction
Conduct fecal egg count before
Fecal egg count 7-10 days after
Control group to confirm
DrenchRite® (Univ. of GA)
Larval development assay
< 95 % egg reduction
< 60 % egg reduction
** Caused by overuse and misuse of drugs. **
60. Anthelmintic resistance
SafeGuard® & Valbazen®
Still Effective in many places
** Caused by overuse and misuse of drugs. **
61. Slowing Down Drug Resistance
DO NOT overuse drugs, especially
Levamisole and Moxidectin.
DO NOT introduce resistant-worms to
Isolate new animals and deworm
them with anthelmintics from two
different chemical classes.
DO NOT underdose
Weigh animals or dose for heaviest
animals in group.
DO NOT rotate dewormers after each
Rotate dewormers annually
Rotate among drug families
Use specific dewormers for specific
DO NOT treat everybody
Leave some animals untreated
In refuge from the drug
What is refugia?
Worms not exposed to
susceptible to treatment.
Increase the population of
Selective treatment –
leave some animals
After deworming, do not
move animals to a clean
You do not have to deworm every animal.
63. Parents How We Select for
64. Maximize the effect of a
Give proper dose; do not
Deposit anthelmintic in esophagus
(not mouth) to prevent drug from
Fast animals to increase efficacy of
Use higher dose for goats than
listed on label. Goats usually
require 1.5-2X the sheep/cattle
Consult with veterinarian for proper dose
Use drugs from two different
chemical classes to get a
65. Routes of administration
Most effective ?
Easier to administer
Easy to administer
Sick animal won’t eat
Stays in system longer,
Potential for abscesses
Not formulated for
sheep and goats
Hard to calibrate
Hard to administer over tongue
Don’t have to buy as much
Choose . . .
1- Sheep Products
2- Cattle Products
3- Horse Products
66. Periparturient egg rise
Temporary loss of immunity to
parasites at the time of
parturition. Egg counts ↑
Often coincides with hypobiotic
larvae resuming their life cycles
in the spring.
Dams are the primary source of
infection to their offspring.
Deworm with an anthelmintic that is
effective against hypobiotic larvae.
Increase protein in late gestation ration
to counter egg rise.
67. When should you deworm
sheep and goats?
Use fecal egg
the need for
68. Fecal Egg Analysis
Qualitative vs. Quantitative
69. Fecal Egg Counting
Shows presence or
absence of eggs
Identify egg types
Shows general trends
in egg numbers.
number of eggs per
gram of feces (epg)
Uses known quantity
of feces and flotation
70. Fecal Egg Counting
What you need
Microscope (min. 100x)
• Mixing vial and strainer for
• Calibrated mixing vial and
syringe for quantitative
• Regular slides and cover
slips for qualitative
• McMaster egg counting
slide for quantitative
71. What do fecal egg counts tell you?
Potential pasture contamination.
Fecal egg counts are not
mathematically correlated to
worm numbers or the severity of
Monitor and maintain low egg
counts; deworm when appropriate
to keep contamination of pasture
Determine the efficacy of
anthelmintic treatment by
comparing paired samples from
the same animals (treatment and
Compare parasite resistance
among animals in the same
72. Paracount-EPG™ Fecal Analysis Kit
(Advanced Equine Products)
5004 – 228th Ave. SE
Issaquah, WA 98029
$50-60 for kit
$15 each for two slides
$20 for green grid
and Selective Deworming
• System developed in South
Africa in response to the
emergence of severe
• A system to assess
(barber pole worm)
infection in sheep and goats
and the need for deworming
• Named for its originator:
Dr. Francois “Faffa” MAlan CHArt
1 Red > 28 No
2 Red-Pink 23-27 No
3 Pink 18-22 ?
4 Pink-White 13-17 Yes
5 White < 12 Yes
Deworm adults at scores 4 and 5*
Treat lambs and kids at
categories 3, 4, and 5
*South Africa recommends goats
be treated at categories 3, 4, and 5
• Reduces the number of treatments
by determining which animals to
treat vs. treating the whole flock.
• Reduces rate at which worms
become resistant to drugs by
increasing “refugia” – worms that
are still susceptible to drug
• Identifies animals that need
treatment most often and vice
versa; thus offering the
opportunity for genetic selection
for parasite resistance.
Resistance is 20-40 percent
20-30 percent of flock harbor most
of worms and are responsible for
most of the egg output.
• Only useful where Haemonchus
contortis is the primary parasite
• Cannot be used in a vacuum; other
factors need to be considered when
making treatment decisions. Ex:
 Bottle jaw
 Body condition
 Fecal consistency
 Evidence of scouring
 Age and susceptibility of animal
• There are other causes of pale or
red eye lids.
• Should be incorporated into an
integrated parasite management
(IPM) program that includes proper
anthelmintic use, pasture rest and
rotation, fecal egg counting, mixed
species grazing, etc.)
78. Must know if anthelmintic is
How often should you check
Depends on season and
Always use card! Compare eye
color to chart. Replace card
after 12 months of use.
Should only be used by
properly trained individuals;
improper use can lead to death
79. Using the FAMACHA© system to control
internal parasites in grazing lambs
Avg FAMACHA Score
# Lambs Dewormed
No. times treated
body condition (and coat condition)
soiling , dags
FIVE POINT CHECK© (5.©)
FOR TARGETED SELECTIVE TREATMENT OF INTERNAL PARASITES IN SMALL RUMINANTS
G.F. BATH AND J.A. VAN WYK, FACULTY OF VETERINARY SCIENCE, UNIVERSITY OF PRETORIA, SOUTH AFRICA
83. Parasite control requires an integrated approach.
Fecal egg counts
Mixed species grazing
Manage anthelmintic resistance
Proper Anthelmintic UseClean(er)
Manage grazing height
Test for anthelmintic resistance
Early or out-of-season