Presentation on parasites for 2015 Maryland Small Ruminant Expo. February 28, 2015.

1. things you should know
about internal parasites
SUSAN SCHOENIAN
SHEEP & GOAT SPECIALIST
UNIVERSITY OF MARYLAND EXTENSION
SSCHOEN@UMD.EDU


2. Many different internal parasites can infect small
ruminants, but your focus should be on two:1. Barber pole worm (Haemonchus contortus)
2. Coccidia (Eimeria species)

3. BARBER POLE WORM
HAEMONCHUS CONTORTUS
Nematode – roundworm
Disease can be chronic or acute
Causes anemia and bottle jaw.
Other symptoms include weight loss, loss of
body condition, poor stamina, and anorexia
Does not usually cause diarrhea
COCCIDIA
EIMERIA SPP.
Single-cell protozoa
Species-specific, even between sheep/goats.
Not all strains are pathogenic
Damages lining of small intestines; damage can
be permanent.
Disease can be clinical or sub-clinical
Diarrhea is most common symptom, but not
always.
Other symptoms
include weight
loss, loss of body
condition, anorexia,
rough hair coat, and
anemia.

4. Worms have developed resistance to all
dewormers and all dewormer classes.
Level of resistance varies by farm and geographic region.
You need to know which one(s) still work on your farm.
And probably even some of the coccidiostats, e.g. Corid®, Bovatec®.


5. How to determine drug resistance
Should do every 2-3 years
FECAL EGG COUNT REDUCTION
TEST (FECRT)
Collect fecal samples from individual
animals (> 250 epg) before and after
treatment with anthelmintic.
Need to collect samples for each drug or
drug combination you want to test, ideally
>15 animals each + an untreated group.
Compare before and after fecal egg counts
to determine percent reduction. Less than
95% indicates that resistance is present.
10-14 days if testing all anthelmintics
Cost ????
DRENCHRITE TEST
LARVAL DEVELOPMENT ASSAY (LDA)
Collect pooled fecal sample from 10 or
more animals (> 350-500 epg).
Send sample to Dr. Ray Kaplan’s lab at
University of Georgia for analysis.
Labor-intensive lab test; takes 3-4 weeks
to get results.
$450 per sample

6. There aren’t any “natural” dewormers (yet)!
But maybe natural products will reduce the number of animals that require deworming.
• With the exception of copper oxide wire
particles (COWPs), there is insufficient
evidence to support claims of the
effectiveness of any “natural” dewormers.
• Natural products alone should not be relied on
for controlling/treating internal parasites.
• If natural products are used, they should be
used in combination with other integrated
parasite management techniques.
• No matter what method of parasite control is
used, it is imperative that animals regularly be
monitored for clinical signs of parasitism and
be dewormed with an effective commercial
dewormer, if so required.

Moringa oleifera

7. Effect of copper oxide wire particles on the parasite status of
bucks in the 2014 Western Maryland Pasture-Based Meat Goat
Performance Test (0.5 g COWP administered on d-42)
0
500
1000
1500
2000
2500
3000
3500
4000
4500
5000
d (-6) d-0 d-14 d-28 d-42 d-56 d-70 d-84
Test - COWP
Study - no COWP

8. Fecal egg or oocyte counts are not indicative of the
need to treat for worms or coccidiosis. • It is normal for there to be some eggs in sheep and goat feces.
• Because there are so many factors involved, fecal egg counts
should not be used to determine the need for deworming an
individual animal.
• The decision to deworm should be based on the observation of
clinical signs: anemia, bottle jaw, weight loss, scours, etc.
• Fecal egg counts should be used to…
1. Determine the effectiveness of deworming
(before and after fecal treatments).
2. Monitor pasture contamination.
3. Identify resistant and susceptible animals in the flock or herd.A qualitative fecal analysis is of limited
value. Don’t waste your money on a
simple fecal flotation.

9. 0
500
1000
1500
2000
2500
3000
3500
4000
d (-6) d-0 d-14 d-28 d-42 d-56 d-70 d-84
Most resistant buck All bucks (avg)
IDENTIFYING RESISTANT ANIMALSMONITORING PASTURE CONTAMINATION
0
500
1000
1500
2000
2500
3000
3500
4000
Arrival d-0 d-14 d-28 d-42 d-56 d-72 d-84
2012 2013 2014

10. Who’s most susceptible to parasites on your farm?❺
PERIPARTURIENT FEMALES LAMBS AND KIDS
• Slow to develop immunity to parasites.
• Development of immunity varies by
parasite.
• Development of immunity varies between
breeds and between animals.
• Continued exposure to parasites is
necessary to develop and maintain
immunity.
• High challenges can overwhelm immunity
and cause disease.
• Small ruminant females suffer a
temporary loss of naturally-acquired
immunity around the time of parturition.
• It may start 2-4 weeks before parturition
and last for up to 6-8 weeks after.
• The eggs deposited during the
periparturient egg rise are largely
responsible for the infections that lambs
and kids acquire during summer grazing.

11. Options for dealing with the periparturient egg rise
MANAGEMENT
Increase level of protein in late gestation ration.
Keep flock/herd indoors or in dry lot during
periparturient period.
DEWORMING
Deworm ewes/does after first killing frost to
eliminate hypobiotic worms.
◦ Use dewormer that is effective against hypobiotic
larvae.
◦ Leave a few ewes/does untreated.
Deworm pregnant females during last month of
pregnancy.
◦ Use dewormer that is effective against hypobiotic
larvae.
◦ Leave a few ewes/does untreated.
Targeted selective treatment (TST) - only treat
ewes/does that require it based on FAMACHA©
scores and Five Point Check®.

12. All dewormers should be administered orally.
Use a syringe with a longmetal nozzleto deposit drug over tongue.
• Drenches are the only anthelmintics FDA-
approved for sheep and goats, with the
exception of Rumatel (feed product).
• The extra-label use of an injectable
dewormer would be difficult to justify
(in sheep).
• Injectables have longer withdrawal periods
than oral formulations.
• Pour-on dewormers were not developed for
goat hair and sheep wool (or hair).
• Due to sub-therapeutic levels of drugs being
in the system, injectables and topical
dewormers promote drug resistance.


13. Only a licensed veterinarian has the legal right to use
or prescribe a drug “extra label.”
SHEEP
• Ivomec®, Valbazen®, Cydectin® and
Prohibit® drenches are all FDA-approved
for sheep at the labeled dosages.
• Unless a higher dose is deemed
necessary, there is no reason for sheep
producers to use anthelmintics “extra-
label”.
• Withdrawal periods are not always known
when anthelmintics are used extra-label.
GOATS

• Only SafeGuard® and Rumatel® are FDA-
approved for goats at the labeled dosages.
• Valbazen® is approved to treat liver flukes
in goats.
• Because of the ineffectiveness of approved
drugs, extra-label drug use is almost always
required to effectively treat goats for
worms.
• There are more violative drug residues in
goats than any other species, mostly
because of “off-label” use of anthelmintics.

14. On some farms, coccidiosis is a more serious problem
than stomach worms such as H. contortus.
Prevention of coccidiosis starts with
good management, nutrition, and
sanitation.
Coccidiostats in mineral, feed, and
water can help prevent disease
outbreak and reduce sub-clinical
disease.
 Bovatec® (lasalocid)
 Rumensin® (monensin) 
 Deccox® (Decoquinate)
 Corid® (amprolium)
Clinical coccidiosis is treated with
amprolium (Corid®) and sulfa drugs (e.g.
Di-Methox®)
❽

15. Genetics offers the best long-term solution for
controlling internal parasitism in small ruminants.• Parasite resistance varies by species, breed, and individual.
• Genetic change is permanent

16. Genetic selection for parasite resistance
PARASITE RESISTANCE
If animal gets infected
Measured by number of worms in gut
Estimated by fecal egg counts (FEC)
Moderately heritable
PARASITE RESILIENCE
How animal tolerates infection
Measure by packed cell volume (PCV)
Estimated by FAMACHA© score
Moderately heritable

17. If you’re losing a lot of animals or having to worm them
a lot, you’re probably doing something wrong!• Your stocking rates are too high.
• Your pastures are too contaminated.
• Your animals need to be on a higher plan of nutrition.
• You’re using ineffective dewormers.
• You’re under-dosing your animals.
• Your animals are too susceptible.

18. Integrated parasite management (IPM)
1) MANAGEMENT
Reducing stocking
rates
Pasture rest and
rotation
Clean or safe
pastures
Zero grazing
Alternative forages
2) TREATMENT
Targeted selective treatment (TST) using the
FAMACHA© System and Five Point Check©
Five checkpoints
1. Eye (FAMACHA score)
2. Jaw (bottle jaw)
3. Back (body condition score)
4. Tail (dags, scours)
5. Nose (nasal bots)
Coat (coat condition)
Proper use of anthelmintics
Browsing
Annual forages
Multi-species
grazing
Mowing and haying
Minimum grazing
height
Genetic selection

19. Thank you for your attention. Questions? Comments?
SUSAN SCHOENIAN
SHEEP & GOAT SPECIALIST
UNIVERSITY OF MARYLAND EXTENSION
SSCHOEN@UMD.EDU