Presentation for 18th Annual Symposium of Dairy Sheep Producers of North America. October 2012.

1. SUSAN SCHOENIAN (Shāy-ne-ŭn)
EXTENSION SHEEP & GOAT SPECIALIST
WESTERN MARYLAND RESEARCH & EDUCATION CENTER
sschoen@umd.edu - www.sheepandgoat.com

2.  Primary health problem
affecting sheep and
lambs, especially east of
the Rockies.
 Severity varies by
• Geographic region
• Production system
 Control is limited by
effectiveness of anti-
parasitic drugs (called
anthelmintics).

3.  Eliminate parasites
1. Prevent clinical
disease, production
losses, and
mortality, and …
2. Slow down drug
resistance.

4. LACTATING EWES
PERI-PARTURIENT EGG RISE
EARLY WEANED LAMBS

5.  Parasite biology
 Integrated parasite
management (IPM)
1. Pasture management
2. Animal factors/
management
3. Deworming
 Anthelmintics
 Anthelmintic resistance

6. 1. Multi-cellular
(Helminths)
a) Nematodes
(roundworms)
b) Cestodes
(tapeworms)
c) Trematodes
(flukes)
2. Single-cell
(protozoa)

7. 1. Strongyle
2. Lungworms
3. Meningeal
worm

8.  Haemonchus
contortus
 Teladorsagia
(Ostertagia)
 Trichostrongylus
 Nematodirus
 Oesophagostomum
 Cooperia
 Trichuris ovis
 Bunostomum

9.  Short, direct life cycles that are
weather-dependent. L4, adult
 Can overwinter on pasture.
 Ability to go into hypobiotic
(arrested) state (in host) when
environmental conditions are not L3
conducive to their development.
 Vary in their egg laying ability. L1
L2
 Eggs look same under
microscope.

10.  Primary parasite
affecting sheep and
lambs in warm, moist
climates and/or with
summer-dominated
rainfall.
 Most pathogenic
species
 Blood-sucker
Image from University of Georgia
 Prolific egg layer

11. SYMPTOMS
(due to blood and protein loss)
 Anemia (paleness)
 Edema - “bottle jaw”
(accumulation of fluid)
 Not usually diarrhea
 Weight loss
 Loss of body condition
 Poor stamina
 Sudden death

12. SYMPTOMS
(usually additive w/barber pole worm)
 Production loss
 Weight loss
 Dagginess
 Scours (diarrhea)
 Only occasional
death
Image source: NADIS UK

13.  Usually not significant
 Usually additive in effect
 Possible respiratory
symptoms
 Coughing
 Irritated airways
 Pneumonia
 Difficult to diagnose
 Usually no clinical signs
 Larvae (not eggs) in feces
 Post-mortem diagnosis

14.  Normal parasite of
white tail deer.
 Sheep are an abnormal host.
 Ingest intermediate host
(snail or slug)
 Larvae migrates into central
nervous system where it
causes neurological disease
(various symptoms).
 Treat with repeated doses of
fenbendazole and anti-
inflammatory drugs.
 Monthly treatments with
ivermectin have been used
as a preventative (camelids).
Paralaphostrongylus tenius

15.  Indirect life cycle; require
pasture mite as an
intermediate host.
 Tend to be non-
pathogenic
 Usually no benefit to
treatment.
 Treat with albendazole
(Valbazen®), fenben-
dazole (Safeguard®, or
praziquantel (Quest Plus®). Moniezia expansa

16.  Regional problem Fasciola hepatica
(Gulf States, Pacific Northwest)
 Require an intermediate
host (snail or slug)
 Infect bile ducts - liver damage
 Diagnosis based on finding eggs
in feces and post-mortem
 Similar symptoms as barber
pole worm (anemia and bottle jaw)
 Treat with albendazole (Valbazen®)
or clorsulon (Ivomec® Plus).

17.  Species-specific
 10 species known to
infect sheep, but not all
are pathogenic.
 More complicated life cycle
than most roundworms.
 Cause damage to cells
lining small intestines.
 Most prevalent
 Indoor pens
 Feed lots Eimeria spp.
 Intensive grazing areas

18. FECAL EXAM CLINICAL SIGNS
 Of limited value –  Adults are largely
shouldn’t use as sole immune, but serve as a
diagnostic tool reservoir of infection.
 Lambs (1-6 mos., esp. 4-8
 Can have clinical coccidiosis
with low oocyte count and wks.) are very susceptible.
vice versa.  Scours (diarrhea)
 Not all species of coccidia  Open fleece
are pathogenic.  Weight loss
 Is normal to find coccidia  Anorexia
oocytes in fecal samples.  Dehydration
 Weakness

19.  Good sanitation
 Coccidiostats in
feed, mineral, water,
and/or milk replacer.
 Lasalocid (Bovatec®)
 Monensin (Rumensin®)
 Decoquinate (Deccox®)
 Amprolium (Corid)

20.  Medicate water or drench
individual animals
(preferable).
 Anthelmintics
1. Amprolium (Corid)
2. Sulfa antibiotics
▪ Di-Methox®
▪ Sulmet®
All Tx’s require veterinary Rx.
 Supportive therapies

21.  A method of
controlling parasites
using a combination
of chemical and non-
chemical means.
1. Non-chemical
▪ Pasture management
▪ Animal management
2. Chemical
▪ Proper and judicious
use of drugs

22. 1) Safe pastures
2) Low risk
pastures
3) Evasive grazing
4) Strip grazing
5) Rotational
grazing
6) Multi-species
grazing

23. Chicory
7) Compost manure
before spreading
8) Alternative
forages
9) Minimum grazing
height
10) Delay grazing
11) Night penning
12) Zero grazing Sericea lespedeza

24. 1) Host immunity
2) Lambing
management
3) Nutrition
4) Genetics

25. 1. FAMACHA©
System
2. Five Point
Check©
 Fecal egg
counting

26.  A system developed in
South Africa to assess
barber pole worm
infection and determine
the need for deworming.
 Scores estimate packed
cell volume (PVC) by
measuring anemia using Eye lid color PCV Treatment recommendation
a color eye chart. 1 Red > 28 Optimal No
2 Red-Pink 23-27 Acceptable No
 Each score has a 3 Pink 18-22 Borderline ?
treatment 4 Pink-White 13-17 Dangerous Yes
recommendation. 5 White < 12 Fatal Yes

27.  An extension of the
FAMACHA© system that
includes evaluation
criteria for other
important internal (and
external) parasites.
 Includes five check points
on the animal:
1. Ocular membrane (eye)
2. Bottle jaw
3. Body condition score
4. Dag score (scours)
5. Nasal discharge (nose bots)

28.  Determining the number of worm eggs
per gram of feces (EPG) in order to
estimate the worm burden in an animal.
 Egg count includes all strongyle eggs;
cannot differentiate at egg stage.
 Requires a measured amount of feces
and flotation solution. A McMaster slide
is used to count eggs.
 Most veterinarians and many diagnostic
labs do not perform quantitative egg
counts (only simple fecal flotations).

29.  Individual sample to determine need for
deworming individual animal.
 Individual or pooled samples to determine
level of pasture contamination.
 Pooled sample to determine treatment
need in a large flock, where FAMACHA©
and Five Point Check® are not practical.
 Individual samples to determine
effectiveness of anthelmintic treatment
(FECRT) or management strategy.
 Individual samples to determine genetic
differences in parasite resistance.

31. MACROCYLIC
BENZIMIDAZOLES LACTONES NICOTINICS
1. Fenbendazole 1. Avermectins 1. Levamisole
SafeGuard® Ivermectin (Prohibit®)
Panacur® (Ivomec®)
Eprinomectin 2. Pyrantel
2. Albendazole (Eprinex®) (Strongid®)
Valbazen® Doramectin
(Dectomax®) 3. Morantel
3. Oxybendazole (Rumatel®)
Synanthic® 2. Milbimycins
Moxidectin
(Cydectin®)

32. SHEEP AND LAMBS LACTATING DAIRY EWES
 Ivermectin  Withdrawal periods have
(Ivomec® drench) not been established for
lactating dairy ewes.
 Albendazole  Requires extra-label drug
(Valbazen® liquid) use, as prescribed by a
First 30-d gestation licensed veterinarian.
 Moxidectin  Work with veterinarian to
(Cydectin® drench) establish safe withdrawal
periods for milk.
 Levamisole
(Prohibit® drench)

33. ORAL DRENCHES INJECTABLES POUR-ONS
 FDA-approved  Not FDA-  Not-FDA
for sheep. approved. approved.
 Easier to  Sub-  Not developed
administer. therapeutic for sheep skin.
 Clear system levels select for  Less effective.
faster. resistant  Sub-
 Shorter worms. therapeutic
withdrawal  Longer levels select for
periods. withdrawal resistant
 More effective periods. worms.

34. 1) When an anthelmintic
treatment fails to reduce fecal
egg counts by 95% or more;
severe when less than 60%.
2) There is varying degrees of
resistance to all anthelmintic
classes.
 Benzimidazoles - widespread
 Avermectins - widespread
 Moxidectin - emerging
 Levamisole - variable
3) Resistance varies by geographic
location and farm and is
influenced by past anthelmintic
use.

35.  Each anthelmintic family
has a different way to kill
worms.
 Worms develop resistance
to the mechanism of worm
control not individual drugs.
 There is cross resistance
among drugs in the same
family.
 If a different drug in the
same family appears to
work, its efficacy will be
short-lived.

36. 1) Treatment response
2) Fecal egg count
reduction test (FECRT)
▪ Before (d-0) and after fecal
egg counts (d 10-14)
3) DrenchRite® test
Larval development assay (LDA)

37.  Decrease frequency of
treatments.
 Do not treat everyone;
leave some animals
untreated.
 Do not move treated
animals to a clean pasture.
 Do not deworm when
there is a low level of
pasture contamination.
 Re-introduce suceptable
worms.

38.  By exposing worms to
sub-therapeutic levels
of drugs.
1) Underdosing
2) Using injectable
dewormers
3) Using pour-on
dewormers
4) Depositing drug into
mouth instead of
esophagus.
5) Persistent activity
dewormers (?)

39. For sale
 To prevent the Ram - $1,000
Resistant worms - free
introduction of
resistant worms to
your
farm, deworm all
newly acquired
animals with
anthelmintics from
all three chemical
classes.

40. NATURAL “ANTHELMINTICS” NEW ANTHELMINTICS
 Copper oxide wire particles  Monepantel (Zolvix®)
 Copper sulfate  Derquantel + abamectin
 Nicotine sulfate (Startect®)
 Diatomaceous earth
 Pumpkin seed
 Garlic  Nematode trapping fungus
 Papaya
 Sericea lespedeza FUTURE (?)
(leaf meal)  Vaccine for Haemonchus
? Pine bark contortus (in development)
? Others

41.  American Consortium for Small Ruminant Parasite Control
wormx.org
acsrpc.org
wormcontrol.org
controlworms.org
 Maryland Small Ruminant Page
www.sheepandgoat.com
 Sheep 201: A Beginner’s Guide to
Raising Sheep
www.sheep101.info/201/parasite.html
 Today’s PowerPoint presentation
www.slideshare.com/schoenian

42. Thank ewe for your attention.
Lambs are 69% Katahdin x 31% Lacaune.