Joan M BurkeResearch Animal Scientist

USDA, ARS, Dale Bumpers Small Farms Research Center

Booneville, AR

Innovations in Parasite Research

Dale Bumpers Small

Farms Research Center

Mission: To develop

scientific principles and

technologies to

enhance the

profitability of small

scale farms.

Gastrointestinal Parasites• Haemonchus contortus or barber pole worm is the most

pathogenic, and thrives in warm, humid climates. Others include Trichostrongylus spp., Teladorsagia circumcincta; Cooperia, Oesophagostomum, Trichuris and Nematodirusare less pathogenic.

• One of greatest health issues, causing anemia, reduced weight gains, poor performance, and death.

Gastrointestinal Parasites

• Haemonchus contortus present in most states and Canada, and survives winter conditions in northern states.

• Widespread anthelmintic resistance

Current RecommendationsAmerican Consortium for Small Ruminant Parasite Control

(www.wormx.info)

• Selective treatment with anthelmintics – use 3-way combination

• Copper oxide wire particles – specific for H. contortus; combined with dewormer increases efficacy.

• Underlying strategy relies on anthelmintics failing many farmers, causing them to exit industry.

Parasite Control

• Condensed tannin rich forages, fresh or dried – reduces

fecundity of worms, but not always effective, trace

mineral deficiency, reduced efficacy of ivermectin.

• Feedlot or avoidance; cut and carry.

• Grazing management.

Credit:Dean Avril, Ministries of Agriculture and Fisheries

Year

FE

CR

, %

0

20

40

60

80

100

2008 2009 2010 2011 2012 2013 2015 2016

32

39

28

38

36

26 67

34

FEC reduction of goats entered into Western MD Pasture-based Meat Goat Performance Test

FEC reduction of goats entered into Oklahoma Forage Based Meat Goat Buck Test

Year

FE

CR

, %

0

20

40

60

80

100

2014 2015 2016 2017

39

18

37

43

GIN in check

Nutrition

Grazing

Biology of animal/

GIN

Stress

Genetics

Climate/

Environment

Chemical Control/COWP

System of Parasite Control

Environmental factors that influence GI

infection

• Rainfall, humidity, temperature

• Season

• Management

• Stocking rate

• Nutrition/body condition

• Sex

• Stress

Day of age/Month

90 120 150 180 210

Fecal

eg

g c

ou

nts

(eg

gs/g

)

0

1000

2000

3000

4000

Winter born

Fall born

AprJan

MayFeb

JunMar

JulApr

AugMay

Day of age/Month

90 120 150 180 210

Pa

cke

d c

ell

vo

lum

e (

%)

22

24

26

28

30

32

34

Winter born

Fall born

AprJan

MayFeb

JunMar

JulApr

AugMay

Effect of season of birth on GI infection

Most worm transmission occurs during the peri-parturient period.

Body condition of the dam, litter size, and age will influence her performance and worm

egg output, as well as the lamb’s.

Changes in dam FEC during PPR(Notter, Burke, et al., 2017)

Days postpartum

-20 0 20 40 60 80

FE

C, eg

gs/

g

0

100

200

300

400

Lamb age, d

30 50 70 90 110 130 150

FE

C, eg

gs/

g

0

200

400

600

800

1000

1200

Changes in lamb FEC with age(Notter, Burke, et al., 2017)

Mandonnet et al., 2001, JAS 79:7

• Relationshipbetween FEC and sire effect – more significant as infection increased.

• Heritability as high as 0.37, but not in U.S.

Parasite resistance in goats

Parasite resistance in sheepHeritability as high as 0.5, but likely lower

Tools for Selection

• Performance tests

• NSIP – provides predictable, economically important genetic evaluation information to the American sheep industry by converting performance records into relevant decision-making tools.

• EBVs – estimated breeding values; inherited genetic potential from sire and dam.

Using NSIP to select for parasite resistance

• NSIP allows recording of FEC at 3 different ages:

• Weaning (42 to 90 d)

• Postweaning (90 to 150 d)

• Yearling/adult

• Weaning FEC are generally collected at the time the lambs are first dewormed, but is influenced by anthelmintic resistance and use.

FEC and PCV of offspring sired by Katahdin rams A or B (Year 2004, 2005) at 120 d of age (Burke & Miller, 2008

Vet. Parasitol. 153, 85)

Year

2004 2005

FE

C,

eg

gs

/g

0

2000

4000

6000

8000

10000

12000

Ram B

Ram A

Year

2004 2005

PC

V,

%

15

20

25

30

35

40

Ram B:

WWEC = +178

PWEC = +119

Ram A:

WWEC = -21

PWEC = -3

The effect of sire's PFEC EBV on PCV of offspring at 120 d

PFEC

-100 0 100 200 300

PC

V, %

20

21

22

23

24

25

26

27

y = (25.2 – 0.67) – 0.016x

P < 0.001

(twin ram)

• Similar relationship at 90 d of age (P < 0.02)

The effect of sire's PFEC EBV on FAMACHA of offspring at 120 d

PFEC

-100 0 100 200 300

FA

MA

CH

A

3.1

3.2

3.3

3.4

3.5

3.6

3.7

3.8

3.9

y = (3.42 – 0.04) + 0.0016x

P < 0.001

(twin ram)

• Similar relationship at 90 d of age (P < 0.001)

Parasite resistance in sheep

Genetic trends for other traits

WWT PWWT

MWWTNLW

Points to consider

• For some traits, there are some slight antagonisms with FEC, but likely not to cause disruptions in breeding goals.

Variable

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

BWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT 0.150.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44

0.160.85 -0.29 0.10 0.18 0.07 0.08 0.04

PWWT0.37 0.81

0.20-0.38 0.01 0.20 0.11 -0.03 0.29

WFEC0.01 -0.07 -0.10

0.190.82 0.27 0.32 0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29

0.240.38 0.40 0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06

0.090.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74

0.060.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02

0.350.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46

0.24

Variable

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

BWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12

-0.10 0.01

WWT0.44 0.16 0.85 -0.29 0.10 0.18 0.07

0.08 0.04

PWWT0.37 0.81 0.20 -0.38 0.01 0.20 0.11

-0.03 0.29

WFEC0.01 -0.07 -0.10 0.19 0.82 0.27 0.32 0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24 0.38 0.40 0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02 0.35 0.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46 0.24

Variable

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

BWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25

0.16 0.12-0.10 0.01

WWT0.44 0.16 0.85 -0.29 0.10

0.18 0.070.08 0.04

PWWT0.37 0.81 0.20 -0.38 0.01

0.20 0.11-0.03 0.29

WFEC0.01 -0.07 -0.10 0.19 0.82 0.27 0.32 0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24 0.38 0.40 0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02 0.35 0.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46 0.24

Variable

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

BWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44 0.16 0.85

-0.29 0.100.18 0.07 0.08 0.04

PWWT0.37 0.81 0.20

-0.38 0.010.20 0.11 -0.03 0.29

WFEC0.01 -0.07 -0.10 0.19 0.82 0.27 0.32 0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24 0.38 0.40 0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02 0.35 0.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46 0.24

Variable

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

BWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44 0.16 0.85 -0.29 0.10 0.18 0.07 0.08 0.04

PWWT0.37 0.81 0.20 -0.38 0.01 0.20 0.11 -0.03 0.29

WFEC0.01 -0.07 -0.10 0.19

0.820.27 0.32 0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24 0.38 0.40 0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02 0.35 0.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46 0.24

Variable

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

BWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44 0.16 0.85 -0.29 0.10 0.18 0.07 0.08 0.04

PWWT0.37 0.81 0.20 -0.38 0.01 0.20 0.11 -0.03 0.29

WFEC0.01 -0.07 -0.10 0.19 0.82

0.27 0.320.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24

0.38 0.400.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02 0.35 0.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46 0.24

Variable

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

BWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44 0.16 0.85 -0.29 0.10 0.18 0.07 0.08 0.04

PWWT0.37 0.81 0.20 -0.38 0.01 0.20 0.11 -0.03 0.29

WFEC0.01 -0.07 -0.10 0.19 0.82 0.27 0.32

0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24 0.38 0.40

0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02 0.35 0.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46 0.24

Variable

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

BWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44 0.16 0.85 -0.29 0.10 0.18 0.07 0.08 0.04

PWWT0.37 0.81 0.20 -0.38 0.01 0.20 0.11 -0.03 0.29

WFEC0.01 -0.07 -0.10 0.19 0.82 0.27 0.32 0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24 0.38 0.40 0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88

0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06

0.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02 0.35 0.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46 0.24

Variable

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

BWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44 0.16 0.85 -0.29 0.10 0.18 0.07 0.08 0.04

PWWT0.37 0.81 0.20 -0.38 0.01 0.20 0.11 -0.03 0.29

WFEC0.01 -0.07 -0.10 0.19 0.82 0.27 0.32 0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24 0.38 0.40 0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02 0.35

0.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46 0.24

VariableBWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44 0.16 0.85

-0.290.10 0.18 0.07 0.08 0.04

PWWT0.37 0.81 0.20

-0.380.01 0.20 0.11 -0.03 0.29

WFEC0.01

-0.07 -0.100.19 0.82 0.27 0.32 0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24 0.38 0.40 0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02 -0.13 0.15 0.16 0.02 0.02 0.35 0.96

PPR300.00 0.00 -0.06 0.19 0.19 0.02 0.02 0.46 0.24

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

VariableBWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44 0.16 0.85 -0.29 0.10 0.18 0.07 0.08 0.04

PWWT0.37 0.81 0.20 -0.38 0.01 0.20 0.11

-0.03 0.29

WFEC0.01 -0.07 -0.10 0.19 0.82 0.27 0.32 0.56 0.77

PWFEC0.07 -0.01 -0.02 0.29 0.24 0.38 0.40 0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02

-0.130.15 0.16 0.02 0.02 0.35 0.96

PPR300.00 0.00

-0.060.19 0.19 0.02 0.02 0.46 0.24

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

VariableBWT WWT PWWT WFEC PWFEC NLB NLW PPR0 PPR30

BWT0.15 0.53 0.45 0.10 0.25 0.16 0.12 -0.10 0.01

WWT0.44 0.16 0.85 -0.29 0.10 0.18 0.07 0.08 0.04

PWWT0.37 0.81 0.20 -0.38 0.01 0.20 0.11 -0.03 0.29

WFEC0.01 -0.07 -0.10 0.19

0.820.27 0.32

0.56 0.77

PWFEC0.07 -0.01 -0.02

0.290.24 0.38 0.40

0.56 0.73

NLB-0.04 0.02 -0.06 0.04 0.06 0.09 0.88 0.13 0.11

NLW0.00 0.02 -0.06 0.04 0.05 0.74 0.06 0.14 0.14

PPR0-0.03 -0.02 -0.13

0.15 0.160.02 0.02 0.35

0.96

PPR300.00 0.00 -0.06

0.19 0.190.02 0.02

0.460.24

Estimates of heritabilities (on the diagonal) and direct additive (above the diagonal) and phenotypic (below the diagonal) correlations for measures of lamb and ewe performance in Katahdin sheep

Variable

Additive maternal effect for:

BWT WWT PWWT

Maternal BWT 0.16 0.58 0.58

Maternal WWT 0.58 0.10 0.99

Maternal PWWT 0.58 0.99 0.12

WFEC -0.04 0.05 0.21

PWFEC -0.01 0.10 0.29

NLB -0.36 -0.07 -0.02

NLW -0.03 0.08 0.11

PPR0 0.06 -0.08 -0.08

PPR30 0.06 0.09 0.10

Estimates of maternal heritabilities for lamb BW and correlations between maternal additive effects on BW and direct additive effects on other measures of lamb and ewe performance in Katahdin sheep

Variable

Additive maternal effect for:

BWT WWT PWWT

Maternal BWT 0.16 0.58 0.58

Maternal WWT 0.58 0.10 0.99

Maternal PWWT 0.58 0.99 0.12

WFEC -0.04 0.05 0.21

PWFEC -0.01 0.10 0.29

NLB -0.36 -0.07 -0.02

NLW -0.03 0.08 0.11

PPR0 0.06 -0.08 -0.08

PPR30 0.06 0.09 0.10

Estimates of maternal heritabilities for lamb BW and correlations between maternal additive effects on BW and direct additive effects on other measures of lamb and ewe performance in Katahdin sheep

Variable

Additive maternal effect for:

BWT WWT PWWT

Maternal BWT0.16 0.58 0.58

Maternal WWT0.58 0.10 0.99

Maternal PWWT0.58 0.99 0.12

WFEC-0.04 0.05 0.21

PWFEC-0.01 0.10 0.29

NLB-0.36 -0.07 -0.02

NLW -0.03 0.08 0.11

PPR0 0.06 -0.08 -0.08

PPR30 0.06 0.09 0.10

Estimates of maternal heritabilities for lamb BW and correlations between maternal additive effects on BW and direct additive effects on other measures of lamb and ewe performance in Katahdin sheep

Future Research

• Continue to examine interactions of production traits and parasite resistance.

• Development of parasite resistance genomic markers.

• Examine grazing and loafing behavior of parasitized ewes and lambs to predict need for treatment using GPS and drone technology.

Summary

• We probably should not rely on anthelmintics to control gastrointestinal parasites in sheep and goats

• A systems approach of control should be used.

• Farmers can control nutrition, grazing management, minimize stress, and use genetics to include selection for parasite resistance.

• Farmers should understand the biology of the animal and parasite and perhaps alter management to align the two to minimize outbreaks.

American Consortium for Small

Ruminant Parasite Control

(www.wormx.info)

Acknowledgments

• This work is supported by USDA, NIFA, OREI in addition to ARS funding.

• Contributions from D.R. Notter, and the ACSRPC.