IPM

Integrated parasite management (IPM) in sheepSUSAN SCHOENIAN (Shāy-nē-ŭn)Sheep & Goat SpecialistWestern Maryland Research & Education [email protected] - www.sheepandgoat.com

What is integrated parasite management?

IPM

Alt.forages

Browsing

Clean pastures

Nutrition

Manage-ment

Genetics

Grazing Mgt.

Host immunity

Zero grazing

Refugia

“Natural” anthelmintics

Deworm

Integrated means

combining and

coordinating diverse elements

into a whole.

Internet definition

What is integrated parasite management?

CHEMICALDeworm

INTEGRATED NON-CHEMICAL

alternative forages; browsing; clean pastures;

coccidiostats; delayed grazing; FAMACHA©; Five Point Check©; genetic

selection; host resistance; low stocking rates; management; multispecies grazing; “natural”

anthelmintics; nutrition; pasture rest and rotation; grazing height; proper anthelmintic

use; protein supplementation; refugia; sanitation; and zero grazing.

Integrated pest management (IPM) is a method of controlling parasites in a population of animals by using a combination of chemical and non-chemical methods.

[Pfizer Animal Health]

Why is IPM necessary?

Though it varies by farm, worms have developed resistance to ALL of the anthelmintics.

It’s not sustainable (or sometimes even possible) to control internal parasites with drugs alone.

There is a growing interest among producers and consumers alike for more natural methods of pest control.

Why is IPM necessary?Parasitism is a complex interaction between the host, the parasite, and the environment.

AnimalImmunityBehavior

WeatherTemperat

ureMoisture

PasturePlants

Soil

ParasiteBiology

Life cycle

Possible

clinical

disease

What is a parasite?

A living organism (generally undesirable) that exists by stealing the resources produced or collected by another living organism.

[Wiktionary]

barber pole worms in abomasum

There are two kinds of parasites.

INTERNAL (ENDO)

A parasite that lives inside another organism.

EXTERNAL (ECTO)

A parasite that lives on the outside of the animal.

ticks, lice, mites, flies, etc.barber pole worm

There are two kinds of internal parasites.

HELMINTHS

Multi-cellular

1. NematodesRoundworms

2. CestodesTapeworms

3. TrematodesFlukes

PROTOZOASingle-cell

Coccidia Giardia Cryptospordium

VS.

There is a species from each kind that is especially problematic for sheep .

Nematodes (roundworms) Haemonchus contortus

Barber pole worm

Trichostronylus hair or bankrupt worm

Telodorsagia (Ostertagia)medium or brown stomach worm

Paralaphostrongylus teniusMeningeal worm

BunostomumHookworm

Cooperia Small intestinal worm

Nematodirus Threadneck worm

OesophagostomumNodule worm

Strongyloidescommon threadworm

Trichuris oviswhipworm

Lungworms

Barber pole wormHaemonchus contortus

Most deadly.

Found in abomasum

Blood-sucker

Short, direct life cycle

Prolific egg producer

Requires warmth and moisture to complete its life cycle. Warm, moist climates Summer rainfalls

As a mechanism of survival, can go into a hypobiotic (arrested) state.

Is adapting to cooler climates global climate change (?)

Barber pole wormImage source: Dr. Nabavi

(Iran)

Barber pole wormHaemonchus contortus

CLINICAL SIGNS

Sudden death

Gradual weight lossWeaknessPoor staminaDiarrhea constipationAnemia

FAMACHA© score 4 or 5

Sub-mandibular edema “bottle jaw”

Death

“Scour” wormsTeladorsagia (Ostertagia)1, Trichostrongylus2

Same genus.

Affect abomasum1 and small intestines2.

Similar life cycle as barber pole worm

Mixed infections with barber pole worm are common.

Cause reduced performance, ill-thrift and dagginess (diarrhea), occasionally death.

Under the microscope, eggs look the same as barber pole worm eggs.

Meningeal worm Paralaphostrongylus tenius

Roundworm that normally infects white tail deer,but causes little problems.

But causes severe neurological disease when it infects an abnormal host, such as a sheep.

Has indirect life cycle with terrestrial snails and slugs serving as the intermediate hosts.

10-14 days after ingestion of an infective snail or slug, the parasite migrates to the spinal cord (central nervous system) and begins causing damage to neurological tissue.

Sheep are a dead end host. Must necropsy to confirm diagnosis.

Meningeal wormdeer worm, brain worm

CLINICAL SIGNS Variable and similar to other

neurological diseases, such as polio, listeriosis, and rabies.

Weakness Lameness Circling Blindness Head tilt Abnormal behavior Paralysis Death

Meningeal wormTREATMENT -- early --

Repetitive, high doses of anthelmintics [Rx] Ivermectin for 5 days Fenbendazole for 5 days

All anthelmintics have been used to treat meningeal worm infections.

Anti-inflammatory drugs [Rx]

There is no scientific evidence that any of the various treatment protocols are effective.

PREVENTION

Exclude deer

Don’t graze in woods or near ponds.

Avoid grazing poorly-drained pastures.

Reduce snail, slug population.

Preventative treatments with anthelmintics Regular deworming will promote

development of anthelmintic-resistant GI worms.

TapewormsGenus Monezia

Indirect life cycle, with pasture mites serving as the intermediate host.

Worm segments are visible in feces (gross!).

Generally non-pathogenic (disease-causing).

Generally no benefit to treatment for tapeworms alone.

Can treat with fenbendazole (SafeGuard®), albendazole (Valbazen®, or praziquantel.

Over-rated as a

problem because we

can see them!

Liver flukesFasciola hepatica (common liver fluke)

Indirect life cycle, with gastropods serving as the intermediate host.

Can be found everyone, but are mostly a problem in the Gulf States and Pacific Northwest, i.e. cool, wet climates.

Clinical symptoms include anemia, bottle jaw, and weight loss.

Liver flukes can’t be found in a normal fecal egg flotation.

Treat with albendazole (Valbazen®) or Clorsulon [Rx].

Image source: http://www.flickr.com/photos/peteredin/3

386220058/

Coccidia -- Eimeria spp.

Single-cell, spore-forming protozoan parasite.

Complicated life cycle with many stages and both sexual and asexual reproduction Approximately 21 days

10 species known to infect sheep and goats. Not all are pathogenic Host-specific.

CoccidiaDamage cells of small intestines

Subclinical (usually goes undetected - most costly)

Poor performance Performance set-back

(even after treatment)

Clinical Failure to thrive Ill-thrift Open-fleeced Dagginess Diarrhea Anorexia Anemia Dehydration Death

Coccidiosis

PREVENTION

Coccidiostats in feed, mineral, or water. Bovatec® (lasalocid) Deccox® (decoquinate) Rumensin® (monensin)

[Rx] Corid (amprolium) [Rx]

Good management Good sanitation Proper stocking rates

TREATMENT

Drench with Corid (amprolium) or Sulfa drugs (Albon®, Di-methox) [Rx]

Supportive therapy

Coccidiostats, especially Rumensin® can be toxic to horses and dogs.

Parasite identificationHow do you know what kind(s) of parasite are affecting your sheep?

FECAL EGG COUNTS (FEC)

To differentiate between strongyle (stomach) and tapeworm eggs and coccidia oocytes.

Can’t differentiate between strongyle (stomach) worm eggs except Nematodirus)

1. Do-it-yourself2. Public lab 3. Diagnostic lab4. Private lab5. Veterinarian

LARVAL ID

To differentiate between strongyle (stomach) worms (H. contortus, Teladorsagia, and trichostrongyles)

▪ University of Georgia▪ Other universities

LECTIN-STAINING TEST

Determine percent of Haemonchus contortus eggs in a fecal sample Oregon State University University of Georgia

Integrated parasite management

Host immunity Management Clean or safe pastures Multi-species grazing Pasture rest and

rotation Alternative forages Nutritional

management Zero grazing Genetic selection Manage refugia Targeted selective

treatment

Host immunity

Sheep have several defense mechanisms for dealing with internal parasites:

1. Immune exclusion2. Self-cure3. Immunity

a) Innateb) Acquired

IMMUNE EXCLUSION

Ingested larvae fail to establish in heavily infected animals.

SELF-CURE PHENOMENON Adult nematodes are

spontaneously expelled when there is a massive larval invasion over a very short exposure period. Usually observed after

a heavy rain.

Why does it occur (?)▪ Increase in

abomasal pH▪ IgE mediated

hypersensitivity

Host immunity

Immunity (2 kinds) The ability to resist a particular disease.

INNATE (INBORN, NATURAL)

Infection is limited during the initial exposure.

Immunity that occurs naturally as part of an individual’s genetic make-up.

ACQUIRED

Immunity that is not inherited.

Immunity that is acquired during life.

Immunity that results from exposure to the disease.

St. Croix lambs

Crossbred lambs

Immunity

Develops with advancing age and parasite exposure. Not until >4 months of age,

depending upon breed and nematode species.

Preventative anthelmintic treatments interfere with the development of immunity.

Adults are generally immune to parasites, but under stress can break down.

Sheep have a weaker degree of immunity than other livestock, except for goats.

Periparturient egg riseRelaxation of immunity around the time of parturition

Lasts for about 4 weeks

May occur earlier (in pregnancy) if ewes are underfed or under stress.

Primary source of infection for new crop of lambs.

Cause (?) Hypothesis:Lactation after pregnancy Increasing prolactin levels Reduction in IgA antibodies

associated with transfer of maternal antibodies in colostrum

“Spring” periparturient egg rise

If lambing occurs in the spring, it will coincide with the maturation and egg production from previously arrested worm larvae.

Management strategies1. Deworm all ewes prior to

parturition with an anthelmintic that is effective against hypobiotic larvae.

2. Increase protein level of ration during late gestation (by 30%).

3. Selective deworming using FAMACHA© system and/or Five Point Check©.

Host resistanceSheep and lambs vary in their susceptiiblity to parasitism.

MORE SUSCEPTIBLE

Weaned lambs Bummer lambs Late-born lambs Yearlings High-producing

females Periparturient ewe Thin animals Geriatric sheep Unadapted breeds Stressed animals

MORE RESISTANT

Mature sheep Dry ewes Pet sheep Mature wethers Sheep in good body

condition Fat sheep

Management

Good sanitation Use feeders Clean water Avoid

overgrazing Do not graze

below 2 inches. Time lambing to

minimize parasite infections.

Pasture rest and rotation Pasture rotation is a

recommended strategy for controlling internal parasites because it allows the use of cleaner (rested) pastures.

Intensive rotational grazing may not help to reduce parasitism unless rest periods are long enough.

Due to increased stocking rates, management intensive grazing may increase internal parasite problems in sheep and lambs.

It takes about 2 months of rest for a contaminated pasture to become relatively “clean” for sheep grazing.

Use of clean or safe pastures

A pasture that has not been grazed by sheep (or goats) for the past 6 to 12 months.

A pasture that has been grazed by adult cattle and/or horses for the past 6 to 12 months.

New pasture

A pasture that has been renovated with tillage.

A pasture in which a hay or silage crop has been removed.

A pasture that has been rotated with row crops.

A pasture that has been burned.

Alternative forages

Livestock that browse have fewer parasite problems.

Livestock grazing tall-growing forages will have less parasite problems.

80% of parasite larvae is found in the first two inches of vegetative growth.

Grazing tanniferous forages may reduce the effects of parasitism.

Sericea lespedeza Chicory Birdsfoot trefoil

Multi-species grazing

Sheep and goats share the same parasites, but they are different from the parasites that affect adult cattle and horses.

Producers who graze multiple species of livestock report fewer parasite problems with small ruminants.

Cattle and horses “vacuum” sheep/goat pastures of infective worm larvae.

Sheep, goats, and cattle have complementary grazing habits.

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.

Zero grazing

Sheep raised in confinement or dry lot (zero grazing) tend to have fewer worm problems.

Sheep put in confinement or dry lot do not usually get re-infected with worms.

Coccidiosis could still be a problem, if preventative measures are not taken.

Good sanitation Proper feeders Coccidiostats

Genetic selection – two traits Resistance

Ability of host to resist infection

Measured by fecal egg counts (FEC-EPG).

Resilience Ability of host to withstand

challenge and/or infection. For barber pole worm:

measured by packed cell volume (PCV) and estimated by FAMACHA© eye anemia scores.

Genetic selection

Breeds vary in their resistance and resilience to gastro-intestinal parasites.

1. Hair sheep (tropical or West African origin)

2. Gulf Coast Native3. Katahdin4. Dorper

Others (?)

St. Croix

Genetic selection

There is as much difference within breeds as between breeds.

The 80-20 ruleApproximately 20 percent of the flock sheds 80 percent of the eggs onto pasture.

Parasite resistance is are moderately-heritable.H2 = 0.22-0.63 (avg. 0.25)

Selection for parasite resistance will not adversely affect the growth of lambs or fertility of ewes.

Rufugia Rufugia are worms that have not been exposed to anthelmintic treatment.

Do not deworm on a regular schedule.

Do not deworm all animals in a group.

Do not return treated animals to a clean pasture.

Give all anthelmintics orally at the proper dose.

Do not underdose.

Deworm new animals with anthelmintics from 2-3 different chemical classes.

Without refugia, worms will eventually be resistant to all

anthelmintics.

Targeted selective treatmentFive Point check©

Point What to check Which parasites

1 Eye

Paling of ocular membranesFAMACHA© eye anemia score

Barber pole wormLiver fluke

2 Back Body condition score All

3 RearDag scorefecal soilingevidence of scouring

Brown stomach wormHair wormThreadneck wormNodule worm

4 JawSub-mandibular edema (bottle jaw)

Barber pole wormLiver fluke

5 Nose Nasal discharge Nasal bots

FAMACHA© eye anemia score

Eye lid color

Packed cell volume

Treatment recommendation

1 Red > 28 Optimal No

2 Red-Pink 23-27 Acceptable No

3 Pink 18-22 Borderline ?

4 Pink-White 13-17 Dangerous Yes

5 White < 12 Fatal Yes

Body condition score (BCS)

Spine Transverse processes Muscle Fat

1 Individually clearly felt, sharp, obvious

Fingers easily pass underneath Very little No

2 Form a smooth line with deep undulations

Smooth round edges

Concave Very thin

3Only slightly detectable undulations

Well coveredhave to push firmly

to get fingers underneath

Not concaveNot convex

Moderate

4 Only detectable with firm pressure Cannot be

felt at all

Maximally developed

Convex

Thick

5 Not detectable Very thick

Dag Scores

Dag score Description Treatment recommendation

0 No fecal soilingNo indication for

treatment

1 Very slight soiling on edge of tail

No treatment

2 Slight soiling on edge of tail and on each side

Usually no treatment

3 Moderate soiling of tail and woolDag formation

Consider treatment

4Severe soiling extending far into

woolSevere dag formation

Treatment, crutching recommended

5Very severe

watery diarrhea extending to hocks

Treatment and crutching essential

Bottle jawSub-mandibular edema

Nasal discharge

Fecal egg countingeggs per gram of feces (EPG)

Indicates “potential” parasite burden in animal.

Indicates potential parasite contamination.

Use to determine level of drug efficacy.

Use to determine genetic differences in parasite resistance among animals.

Limitations of fecal egg counts

Fecal egg counts are not always well-correlated with disease.

Presence of eggs does not mean that the animal is clinically parasitized and needs treatment.

Absence of eggs or oocytes (coccidia) does not mean that the animal is parasite-free and not in need of treatment.

Fecal egg count interpretation

Three classes of anthelmintics

1)Benzimidizoles2)Nicotinic agonists3)Macrocylic lactones

Benzimidazoles (BZD)

1) Fenbendazole SafeGuard®, Panacur®[Rx]

2) AlbendazoleValbazen®

3) Oxyfendazole Synanthic®[Rx]

Benzimidazoles (BZD)

White dewormers Water soluble Broad spectrum Wide margin of safety Efficacy against tapeworms Efficacy against adult liver

flukes (albendazole) Do not use albendazole

during first 30 days of pregnancy or ram removal.

Widespread resistance Resistance is caused by

dominant gene

Nicotinic agonists

1)   Imidazothiaoles (IMID)

a) LevamisoleProhibit®, Levasol®

2)  Tetrahydropyrimidines (TETR)

a) Morantel [Rx]Rumatel®

b) Pyrantel [Rx]Strongid®

Nicotinic agonists

Levamisole Clear drench Water soluble Broad spectrum of activity Not effective against

arrested larvae Narrower margin of safety Resistance reported Resistance is caused by a

recessive gene

Morantel and Pyrantel Not effective against

larval stages of worms.

Currently off the market:

status unknown.

Macrocylic lactones (ML)

1) Avermectinsa) Ivermectin

Ivomec®b) Doramectin [Rx]

Dectomax®

2) Milbemycins a) Moxidecin

Cydectin® Quest® [Rx]

Macrocylic lactones (ML)

Broad spectrum Wide margin of safety Effective against

(biting) external parasites

Persistent activity

Widespread resistance, reported especially ivermectin

Resistance is caused by dominant gene

How do you know if you have anthelmintic resistance on your farm?

1) DRENCHRITE® LARVAL DEVELOPMENT ASSAY

An in vitro test for the detection of resistance to all anthelmintic groups.

Need pooled fecal sample from 10 or more animals (minimum of 6)at least > 350 epg >500 epg preferred

▪ Animals with FAMACHA© scores of 3, 4, or 5 are more likely to have higher egg counts if barber pole worm is the primary parasite.

2) FECAL EGG COUNT REDUCTION TEST (FECRT)

Comparison of before and after fecal egg counts Benzimidizoles

7 days post-treatment Levamisole

7 days post-treatment Avermectins

14 days post-treatment

Should include “control” (untreated) animals in testing.

Improving (maintaining) the efficacy of treatment

Weigh animals to determine proper dose.

Do not underdose.

Use proper drench technique.

Fast animals prior to treatment with ivermectin or albendazole.

Give multiple anthelmintics Synergetic effect

Maximize refugia

What about natural “anthelmintics?”

An anthelmintic acts to expel or destroy parasitic worms.

Using this definition, there aren’t any consistently effective “natural” anthelmintics.

An animal that is clinically parasitized should be treated with a “chemical” dewormer.

Haemonchosis

What about natural “anthelmintics?”

They may not treat a clinically-parasitized animal, but they may reduce the number of animals that require treatment.

Disruption of parasite life cycle (on pasture)▪ Eat larvae or eggs▪ Inhibit larvae development▪ Inhibit egg hatching

Strengthening of the immune system.

An increasing number of scientific studies are being conducted to identify compounds which

may have anthelmintic-like properties. Current claims are largely antidotal.

Having anthelmintic-like properties

Herbal dewormers [oils and seeds] Artemisia genus (Wormword)

Garlic Papaya Paprika Ginger Pumpkin Mustard

Tanniferous forages Nematode-trapping

fungus Copper oxide wire

particles Copper sulfate Tobacco (nicotine sulfate)

Sericea lespedeza

What about new dewormers?

Zolvix® drench (Monepantel)Amino-Acetonitrile (ADD) classFirst new anthelmintic since 1980’s

Unique mode of action Targets a receptor that

paralyzes the worm Effective against worms that are

resistant to other anthelmintics.

Currently undergoing testing in the U.S. Approval for sheep, if/when [?]

Thank you for your attention.

Any questions?

Susan [email protected]

www.sheepandgoat.com