joan burke's non chemical control of internal parasites

8/8/2019 Joan Burke's Non Chemical Control of Internal Parasites

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Nonchemical Control ofInternal Parasites

Joan M. BurkeResearch Animal Scientist

USDA, Agricultural Research Service

Booneville, AR

www.scsrpc.orgorwww.wormcontrol.org

Annual Conference of the Greater Appalachian Llamaand Alpaca Association


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Selective and nonchemical

approaches to controlparasites

Anthelmintic resistance

FAMACHA

Common sense

Pasture or foragemanagement

Other approaches


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What is Resistance?What is Resistance?

The ability of certain worms in a population to

survive drug treatments that are generally

effective against the same worm species and

stage of infection

Caused by changes in levels of

resistance genes carried by worms in a

population Result of drug treatment that produces

genetic selection of resistant worms in a

population of worms


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What Causes Resistance ToWhat Causes Resistance To

Dewormers?Dewormers?

Lack of Refugia Refugia = the proportion of the worm

population that is not selected by drugtreatment

Worms in untreated animals

Eggs and larvae on pasture

Provides pool of sensitive genes Dilutes resistant genes

Considered the most important factor in

the development of drug resistance


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What Causes Resistance ToWhat Causes Resistance To

Dewormers?Dewormers?

1. Treatment strategies that reduce

refugia

Examples: Treating and moving to clean pasture

Treating when few larvae are on the pasture (drought)

Treating all animals at same time

2. Frequent Treatments > 3 treatments per year

3. Under dosing


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Selective TreatmentSelective Treatment

FAMACHA

ForH. contortus only

For other GI worms

FEC

Age

Body condition

Production level

Symptoms

Short term weight gain


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Concept Behind SelectiveConcept Behind Selective

TreatmentTreatment

Parasites are not equally distributed in

groups of animals

Overdispered / aggregated distributions

20-30 % of animals harbor most of worms

Few animals are responsible for most of egg

output

Number of Worms

Freq


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So, how do we easilydetermine who to treat?


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The FAMACHAThe FAMACHA SystemSystem

Eye color chart with five

color categories

Compare chart with color

of mucous membranes of

sheep or goat

Classification into one of

five color categories: 1 not anemic

5 -- severely anemic


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How Does FAMACHA Work ??How Does FAMACHA Work ??

Since the primary impact ofH.

contortus is anemia, one can

indirectly measure parasite burden(and need for treatment) by

measuring anemia

Only useful where H. contortus isthe primary parasite species


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AnemiaAnemia

Definition a reduction below normalin the number or volume of red bloodcells in the blood

Symptoms depend on degree/severity Sub-mandibular Edema (Bottle Jaw)

Unthrifty Condition

Poor BCS

Broken coat Exercise/Heat intolerance

Pale mucus membranes


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Why use FAMACHAWhy use FAMACHA

Decreased Worm burdens

Creates Refugia

Decreased development

of resistance

Saves money

Identifies animals that need less frequent

deworming -- keep for breeding

Identifies animals that need more frequent

deworming -- cull


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Remember Refugia (In Refuge)Remember Refugia (In Refuge)

Untreated

animals harbor

susceptibleworms

Dilutional effect

Resistancedevelops more

slowly


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Validation of the FAMACHAValidation of the FAMACHA

system in llamassystem in llamas


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Other common sense

approaches Quarantine new animals and deworm

Use Smart Drenching

Correct dose based on weight

Place dewormer in back of mouth

Treat fasted animal when possible


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Other Recommendations

Fix water leaks around troughs

Avoid grass in pens Fence off moist areas

Remove feces

DO NOT overstock

X

X


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Grazing, forage or feeding

management to controlparasites

Multi-species grazing (dilution)Rotational grazing

Nutrition

Use of high quality foragesCondensed tannin-rich forages


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Multi-species grazing


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Rotational Grazing

Reducednumber of

deworming

treatments

Better forage

management


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NutritionEffect of supplement on PCV

Days after inoculation with H. contortus

0 7 14 21 2 8 3 5 42 49 5 6

PCV,%

2 0

2 2

24

2 6

2 8

3 0

3 2

34 Low supplementHigh supplement

*

*

**

**

* *

Nutrition


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Legume forages


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Use ofTannin rich forages

such as sericea lespedeza


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Sericea lespedeza


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Other Strategies

COWP

Genetics

Season of birth

Integrated approach


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COWP available for copper deficiency

COWP can reduce GIN in sheep and goats

and zoo hoofstock

COWP become lodged in the abomasum

resulting in expulsion or death of the adult

nematode

Copper oxide wire particles

(COWP)


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teaspoon = 2 g COWP

000 size capsule


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Eff t f EC

Daysaft r i lati it H. t rt

14 1 4 49

al

t,

/

4

1

1

4

*

**

*

++


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Eff t f COWP PCV

Daysaft r i lati it . t rt s

0 7 14 1 4 49

PCV,%

0

2 2

2 4

2 6

2 8

3 0

3 2

3 4

0 2 46

**

*


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Use of Resistant Breeds


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Genetics

An animals ability toresist parasites isheritable (~0.2 0.5)

USDA, ARS sires are

selected based onparasite resistance(low FEC) andtolerance (lack of

anemia; lowFAMACHA scores)

Year

2004 2005

FEC,egg

s/g

0

2000

4000

6000

8000

10000

12000

Ram B

Ram A


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Influence of season of lambingInfluence of season of lambing

on GIN infection in Katahdinon GIN infection in Katahdinlambslambs

Influence of season of lambingInfluence of season of lambing

on GIN infection in Katahdinon GIN infection in Katahdinlambslambs

J.M. Burke1, J.E. Miller2

1USDA-ARS2Louisiana State University


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Day fage/ t

90 120 1 0 180 210

Fec

alegg

counts(eggs/g)

0

1000

2000

3000

4000

Winter orn

Fall orn

Apran

MayFeb

JunMar

JulApr

AugMay

Effect of season of birth on FEC


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Day of age/Month

90 120 150 180 210

Packedcellvolume(%

)

22

24

26

28

30

32

34

Winter born

Fall born

AprJan

MayFeb

JunMar

JulApr

AugMay

Effect of season of birth on PCV

Weaning


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Integrated Strategy

Use FAMACHA for monitoring infection level

o Cull high infection individuals resistanceselection

o Deworm individuals as necessary

Effective drug smart drenching

Copper oxide wire particles

Sericea lespedeza and other CT forages

Management

o Stocking rate, mixed species grazing, dry lot

Future (??)

o Worm-trapping fungus, vaccine


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AcknowledgmentsAcknowledgments

Southern Consortium for Small RuminantParasite Control (www.scsrpc.org orwww.wormx.org)

USDA, ARS employees

USDA, SARE grant (LS08-204)

joan burke's non chemical control of internal parasites

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