This document provides information on managing internal parasites in small ruminants. It discusses the primary internal parasites affecting sheep and goats, including roundworms, tapeworms, flukes, coccidia, and protozoa. An integrated approach to parasite control is recommended, combining management strategies like grazing management with targeted selective treatment. Key management strategies include developing host immunity, husbandry practices, nutritional management, and genetic selection. Diagnostic tools for targeted treatment include FAMACHA, five point check, and fecal egg counts. Combination dewormer treatments are advised to slow development of anthelmintic resistance.

1. Management of
internal parasites in
small ruminants
SUSAN SCHOENIAN
Sheep & Goat Specialist
University of Maryland Extension
sschoen@umd.edu | wormx.info

2. Situation
• Parasites are the primary health
problem affecting small ruminants
in warm, moist climates.
• Worms have developed varying
degrees of resistance to all of the
dewormer drugs and dewormer
classes.
• Effective parasite control requires
an integrated approach that
combines management (mostly)
with drug therapy (selective).

3. Two primary kinds of internal parasites that
affect small ruminants
HELMINTHS (WORMS)
1. Nematodes
Roundworms
2. Cestodes
Flatworms
Tapeworms
3. Trematodes
Flukes
PROTOZOA (SINGLE-CELL)
1. Coccidia
2. Giardia
3. Cryptosporidium
4. Toxoplasma gondii

4. Roundworms | Nematodes | “Strongyles”
PRIMARY IMPORTANCE
1. Haemonchus contortus
Barber pole worm
2. Trichostrongylus spp.
Scour worms
3. Teladorsagia (Ostertagia)
Brown stomach worm
OTHER ROUNDWORMS
• Nematodirus
Thread-necked worm
• Oesophagostomum spp.
Nodule worm
• Strongyloides (skin penetration)
Threadworm
• Cooperia
Small intestinal worms
• Lungworms
• Parelaphostrongylus tenuis
Meningeal worm***

5. Roundworms
Nematodes
“Strongyles”
• Mixed infections common
• Short, indirect life cycles, ~21 days
• Ability to undergo hypobiosis in order to survive unfavorable weather.
• Eggs look the same. Need to hatch eggs to identify species from larvae.

6. Barber pole worm
Haemonchus contortus
• Primary parasite affecting small
ruminants during grazing season.
• Blood sucking nematode
(abomasum): very pathogenic
• Causes blood loss (anemia),
bottle jaw, weight loss, (not
diarrhea)
• Acute or chronic disease
progression
• Very prolific egg layer

7. Trichostrongyles and
Teladorsagia
Scour worms
• Usually part of mixed infections with Haemonchus
• Sometimes primary infection
• Similar life cycle, less prolific egg layers, lower
egg counts
• Causes digestive upset: loss of body condition
and weight and scours (diarrhea, dags).
• Productivity losses

8. Cestodes
Flatworms
Tapeworms
Moniezia expansa
• Diagnosed by seeing segments in the feces;
usually only visible worm in the feces.
• Indirect life cycle (pasture mite)
• Tend to be non-pathogenic.
• Immunity developed at early age.
• Usually, no treatment benefit.
• Less common: mild ill thrift, intestinal
blockages, gut mobility issues
(enterotoxemia).
• Treat with specific dewormers: albendazole
(Valbazen®), fenbendazole (SafeGuard®), and
praziquantel (in horse dewormers).

9. Meningeal worm
Deer/brain worm
Parelaphostrongylus
• Parasite of white tail deer
• Indirect life cycle (snails, slugs)
• Sheep, goats, and camelids are unnatural (dead
end) hosts.
• Parasite causes various neurological symptoms in
abnormal host: hindquarter weakness, intense
itching, paralysis.
• Treat for five days with high doses of fenbendazole
(SafeGuard®) and anti-inflammatories
(Dexamethasone or Banamine®).
• Help Prevent with monthly ivermectin (Rx)
injections.

10. Coccidia
Eimeria spp.
• Single cell protozoan parasite
• Host-specific
• Not all strains pathogenic
• Causes scours and general ill
thrift in lambs/kids, 1-6
months
• Most common in intensively-
raised animals, but outbreaks
on pasture are not
uncommon.

11. Coccidiosis
PREVENTION
• Good management/sanitation
• Coccidiostats** in feed, mineral,
water, and/or milk replacer
1) Lasalocid (Bovatec®) - sheep
2) Monensin (Rumensin®) - goats
3) Decoquinate (Deccox®) - both
4) Amprolium (Corid®) - extra label
better as a treatment
• Natural: sericea lespedeza**
TREATMENT
• Amprolium (Corid®)
Over-the-counter, but extra label
• Sulfa antibiotics (e.g., Di-Methox®)
Obtain from a vet, extra label
• Ponazuril (Marquis®)
Prescription, extra label, $$$
• Other – drugs used elsewhere in
world (toltrazuril, diclazuril)
**Need to feed several weeks before risk period.
Can be toxic to equines! 

12. Anthelmintic (dewormer) resistance
• Worms have developed resistance
to all dewormers and dewormer
classes.
• Resistance varies by farm and
geographic area.
• While inevitable, resistance was
accelerated by over and
sometimes misuse of drugs.
• Can determine resistance with
fecal egg count reduction tests and
larval development assay
(DrenchRite® test @LSU). 0
10
20
30
40
50
60
70
80
90
100
Benzimidazoles Ivermectin Levamisole Moxidectin
Maryland Virginia Georgia

13. Integrated parasite management (IPM)
MANAGEMENT
• Host immunity
• Husbandry
• Pasture and grazing
management
• Manage periparturient egg rise
• Nutrition
• Genetic selection
• BioWorma®
DRUGS
• Proper dewormer use
• Targeted selective treatment
(TST) – or non treatment
• FAMACHA© system
• Five Point Check©
• Performance criteria

• Manage dewormer resistance

14. Host immunity
• Sheep/goats will eventually develop
immunity to parasites.
• Sheep sooner and more complete than goats
• Resistant breeds/animals sooner than
susceptible breeds/animals.
• Sooner for some parasites
(e.g., tapeworms and coccidia)
• Sheep/goats need continuous exposure to
parasites to develop and maintain immunity.
• Age, nutrition, and reproductive status/level
all have impact on immunity (susceptibility)
to parasitic disease.

15. Most susceptible animals
• Less than six months of
age/exposure
• Poor nutrition
• Other diseases or stresses
• Yearling with > 2 offspring
• Mature female with > 3 offspring
• Poor nutrition
• Other diseases or stresses

16. More resistant breeds
SHEEP
• Hair sheep of Caribbean origin
St. Croix, Barbados Blackbelly
• Hair sheep composites
Katahdin, Royal White®(?), Dorper
• Wool sheep native to Southeast
Gulf Coast Native, Florida Cracker
• Terminal sire
Texel
GOATS (less documentation)
• Landrace breeds
Myotonic, Spanish
• Kiko
• Savanna (?)
• Boer
• Dairy goats
• Angora goats

17. Good Husbandry
• Good sanitation: feed, water, bedding
• Control other diseases
• Lamb/kid at times of the year (or
places) where/when parasites are less
active.
• Don’t wean pasture-reared lambs/kids
too early, < 120 days
• Quarantine drenching: don’t introduce
resistant worms to your farm.

18. Pasture and
grazing
management
• Short grazing periods (< 4 days)
+ Long rest periods ~60 days
• Clean or low risk pastures
• Minimum grazing heights
• Taller growing forages
• Browsing (esp. for goats)
• Mixed swards
• Forages containing condensed tannins
(esp. Sericea lespedeza: AU Grazer)
• Multi-species grazing
• Haying and cropping
• Supplementation (protein, energy)

19. Zero grazing
Dry lot or confinement
• Sheep/goats raised in
confinement usually do not
have problems with parasites
(worms).
• No source of infection or
reinfection
• Dry lots must contain no
vegetation, even on edges
• Coccidia can still be a problem
since it is transmitted via feces.

20. The periparturient
egg rise (PPER)
• Relaxation of immunity (to worms and
coccidia) around the time of
parturition (2 weeks before to 8
weeks after).
• Increased egg and oocyte counts.
• More pronounced in susceptible
breeds, first timers, and females with
multiple births.
• Primary source of infection for
lambs/kids that graze same pastures.

21. Managing the
periparturient
egg rise

22. Nutritional aspects
of parasitism
• Parasitism has been documented to cause
a 10-20% reduction in in feed intake.
• Nutritionally-stressed animals are more
susceptible to parasites.
• Thin animals (<2 BCS) are more
susceptible to parasites.
• Supplemental protein and energy
enhances immune response to parasites.
• Vitamins and minerals also important.
CORRECT DEFICIENCIES IN DIET

23. Genetic selection
PARASITE RESISTANCE = FECAL EGG COUNT
Three options
1) Central performance tests that
evaluate rams/bucks for parasite
resistance
2) Estimated breeding values (EBVs)
for parasite resistance (via NSIP).
3) On-farm selection for parasite
resistance.
All methods require sufficient exposure
to parasites (high enough egg counts
and big enough spread in egg counts).

24. BioWorma® (Duddingtonia flagrans)
• Fungus that traps and kills roundworm larvae in manure of animals.
• Reduces reinfection of pastures, resulting in cleaner pastures.

25. Two BioWorma® products available
BIOWORMA®
• Feed additive that contains
34 percent fungus.
• Dosage is 0.1 oz per 100 lbs.
• Needs to be mixed in a
batch of feed or
supplement.
• Distribution limited to
veterinarians and EPA-
certified feed mixers and
manufacturers.
LIVAMOL® +
BIOWORMA®
• Nutritional supplement
(16% CP) that contains
2.2% fungus.
• Dosage is 1.6 oz per
100 lbs.
• Ready-to-use product
• Mix or top dress on
feed
• Anyone can purchase

26. How to feed BioWorma®
MANUFACTURER
• Feed when parasites
are active, above 40
degrees F.
• Feed to most
susceptible animals in
flock/herd.
1) Periparturient
females
2) Lambs/kids
AMERICAN CONSORTIUM
FOR SMALL RUMINANT
PARASITE CONTROL
• Feed for at least 60
days.
• Pending research
• Feed every other day
• Feed for two weeks
out of month
• Incorporate into
mineral mix

27. Product Cost Amount per oz oz/day $/day $/month $/90 days
Livamol® $ 89.50 15-lb. pail $ 0.37 1.6 $ 0.60 $ 17.90 $ 53.70
Livamol® $ 78.75 15-lb bulk $ 0.33 1.6 $ 0.53 $ 15.75 $ 47.25
Livamol® $ 149.50 30-lb. pail $ 0.31 1.6 $ 0.50 $ 14.95 $ 44.85
Livamol® $ 126.00 30-lb. bulk $ 0.26 1.6 $ 0.42 $ 12.60 $ 37.80
BioWorma® $ 345.00 10-lb. pail $ 2.16 0.1 $ 0.22 $ 6.47 $ 19.41
BioWorma® $ 325.00 10-lb. bulk $ 2.03 0.1 $ 0.20 $ 6.09 $ 18.28
Feed 2 wk/mo $ 325.00 10-lb. bulk $ 2.03 0.1 $ 0.20 $ 3.05 $ 9.14
Cost of feeding BioWorma® (excluding shipping)
Premier 1 Sheep Supplies, 9.12.21

28. Copper oxide
wire particles
(COWP)

29. Proper deworming
• All oral treatments (drenching)
• All drench formulations
• Deworm with oral dosing syringe with
long metal nozzle and bent tip (or
backpack drench gun with same).
• Deposit drug over tongue into gullet.
• Higher dosages for goats
• Low stress handling
• Proper storage of dewormers

30. Targeted selective treatment (TST)
or non-treatment
• Only deworming those that require
treatment or would benefit most from
treatment.
• Leaving a portion of the flock/herd
untreated.
• Reduces deworming
• Increases “refugia”: worms that have
not been exposed to drug; thus,
remain susceptible to treatment.
• Allows animals to develop immunity

31. Decision-making tools for TST
“Chute-side”
1) FAMACHA© eye
anemia system
2) Five Point Check©
3) Performance
4) Fecal egg count

32. FAMACHA© eye
anemia system

33. Five Point Check©
• An extension of the FAMACHA©
system.
• Includes criteria for all worms that
commonly affect small ruminants.
• Five check points on animal’s body.
• Consider all five points when making
deworming decisions. 1. Eye (anemia)
2. Jaw (swelling)
3. Back (body condition)
4. Tail (soiling, dags)
5. Nose (discharge)
1 2 3 4 5

34. Performance as a deworming criteria
• Performance can be used as a criteria to determine deworming need,
especially in combination with other criteria (e.g., FAMACHA© + ADG) and
in areas where barber pole worm is not primary parasite.
Average daily gain (ADG) Number of offspring Level of milk production

35. Role of fecal
egg counts
EPG: eggs per gram of feces
Can help make deworming
decisions but should not be used as
the sole or main criteria.
1. Not chute-side
2. Not always a strong correlation with
clinical disease.
3. Many limitations, e.g., roundworm
eggs look the same (need to hatch to
identify from larvae)
4. No agreed upon thresholds for
treatment.

36. Best uses of fecal egg
counts
• Before and after fecal egg counts
to determine effectiveness of
treatment (individual animals)
• Before and after fecal egg counts
to determine level of dewormer
resistance (10 or more animals).
• Identify resistant and susceptible
animals (e.g., EBVs).
• Monitor pasture contamination.

37. Combination
treatments
• It is now recommended that clinically-
parasitized small ruminants be given
combination treatments: more than one
drug at the same time to kill same kind of
worms.
• Additive effect: gives animal most effective
treatment while slowing down development
of resistant worms.
• Give most potent drug from each class:
albendazole + moxidectin + levamisole
• Withdrawal period is for drug with longest
withdrawal (usually Cydectin®)
• Extra label (Vx) for goats and camelids.
All oral
Full dose
One after the other
Don’t mix

38. Extra label drug use
in small ruminants
• Definition: use of a drug in any manner that is not
specified on the manufacturer’s label: species,
dosage, route of administration, frequency, disease.
• Only a veterinarian may use or prescribe a drug
extra label, and there are rules that govern their
use.
• There are FDA-approved dewormers for sheep in
each drug class (Valbazen®, Ivomec®, Cydectin®,
and Prohibit®/Leva-Med®)
• There are few effective dewormers FDA-approved
for goats (only SafeGuard®, Rumatel®).
• No dewormers are FDA-approved for camelids.
• None of the drugs used to treat coccidia are FDA-
approved for small ruminants.

39. You can learn more.
American Consortium for Small Ruminant Parasite Control (ACSRPC)
• Fact sheets
• Videos
• Images
• Timely Topics
• YouTube channel
• Facebook page
• Conferences
• Research
• Blog
www.wormX.info

40. SUSAN SCHOENIAN
Sheep & Goat Specialist
University of Maryland Extension
sschoen@umd.edu
www.sheepandgoat.com
www.sheep101.info
www.wormx.info
Facebook @ MDSmallRuminant