2006 SARE Group 2006 SARE Group Farmer/Rancher Grant Farmer/Rancher Grant Selecting Sheep for Parasite Selecting Sheep for Parasite Resistance Resistance SARE Project Number: FNC05-583 SARE Project Number: FNC05-583 Kathy Bielek Kathy Bielek Misty Oaks Farm Misty Oaks Farm 1130 Kimber Road 1130 Kimber Road Wooster, OH 44691 Wooster, OH 44691 330-264-5281 330-264-5281 [email protected][email protected]
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2006 SARE Group Farmer/Rancher Grant Selecting Sheep for Parasite Resistance SARE Project Number: FNC05-583 Kathy Bielek Misty Oaks Farm 1130 Kimber Road.
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2006 SARE Group 2006 SARE Group Farmer/Rancher GrantFarmer/Rancher Grant
Selecting Sheep for Parasite Selecting Sheep for Parasite ResistanceResistance
SARE Project Number: FNC05-583SARE Project Number: FNC05-583
Selecting Sheep for Parasite ResistanceSelecting Sheep for Parasite Resistance
Questions & AnswersQuestions & Answers
Courtesy of William Shulaw, DVM, MS
The Parasite ProblemThe Parasite Problem
Parasites affect the health and Parasites affect the health and productivity of sheepproductivity of sheep
Reduced lamb growthReduced lamb growth
Potential death of lambs and ewesPotential death of lambs and ewes
Require expensive chemical dewormersRequire expensive chemical dewormers
Most susceptible are lambs & Most susceptible are lambs & lactating eweslactating ewes
Parasites are developing resistance Parasites are developing resistance to dewormers to dewormers
TREATMENT
RESISTANCE SELECTION IN
ADULT WORMS
Courtesy of William Shulaw, DVM, MS
Why Selection WorksWhy Selection Works Parasite numbers not evenly Parasite numbers not evenly
distributed among all animals in flockdistributed among all animals in flock
Roughly 20% of animals harbor 80% Roughly 20% of animals harbor 80% of parasitesof parasites
Treating only those 20% helps avoid Treating only those 20% helps avoid developing parasites resistant to developing parasites resistant to dewormersdewormers
Identifying and selecting less Identifying and selecting less susceptible replacement animals will susceptible replacement animals will help increase flock’s resistance to help increase flock’s resistance to parasites over timeparasites over time
XXX Farm Daily Egg Output
02000000400000060000008000000
1000000012000000140000001600000018000000
1 4 7 10 13 16 19 22 25 28 31 34 37 40 43 46
all sheep
nu
mb
er o
f eg
gs
103,546,200 eggs per day for just 46 sheep
Just 10 (21%) of the lambs excreted 77% of the eggs !!
Katahdins: The Low Katahdins: The Low Maintenance Meat SheepMaintenance Meat Sheep
Our CollaboratorsOur Collaborators William Shulaw, DVM, MSWilliam Shulaw, DVM, MS
Extension Veterinarian, Beef/SheepExtension Veterinarian, Beef/SheepOhio State UniversityOhio State University
Charles Parker, PhDCharles Parker, PhDProfessor Emeritus, Dept of Animal ScienceProfessor Emeritus, Dept of Animal ScienceOhio State UniversityOhio State University
New CooperatorNew Cooperator David Notter, PhDDavid Notter, PhD
Professor of Animal ScienceProfessor of Animal ScienceVirginia TechVirginia Tech
Dr. Notter directs the National Sheep Improvement Program (NSIP) Genetic Dr. Notter directs the National Sheep Improvement Program (NSIP) Genetic Evaluation Center at Virginia TechEvaluation Center at Virginia Tech
Objectives of The GrantObjectives of The Grant Identify rams with ability to transmit parasite Identify rams with ability to transmit parasite
resistance to offspring resistance to offspring
Compare effect of different management systems Compare effect of different management systems
Investigate method to identify potential Investigate method to identify potential replacement seed stockreplacement seed stock
ToolsTools FAMACHA FAMACHA
Body Condition Scoring (BCS)Body Condition Scoring (BCS)
Compare eye color chart Compare eye color chart with color of mucous with color of mucous membranes of sheep membranes of sheep
1 – not anemic1 – not anemic
5 -- severely anemic5 -- severely anemic
Eye color is an indirect Eye color is an indirect measure of the worm measure of the worm burden – applies toburden – applies to Hemonchus contortusHemonchus contortus only only
Courtesy of William Shulaw, DVM, MS
FAMACHA – FAMACHA – How it WorksHow it Works
Fecal egg Fecal egg counts (FEC) counts (FEC)
using using McMaster McMaster TechniqueTechnique1 egg = 50 1 egg = 50
epgepg
MethodMethod
All lambs identified by sire All lambs identified by sire
All lambs managed together in single All lambs managed together in single group on each farmgroup on each farm
No changes made to management of No changes made to management of each farmeach farm
Detailed Record KeepingDetailed Record Keeping
Collected on all 456 Collected on all 456 lambs:lambs:
Lamb IDLamb ID
Date of birthDate of birth
SexSex
Birth type & rearingBirth type & rearing
Birth weightBirth weight
Sire IDSire ID
Dam IDDam ID
Age of DamAge of Dam
Deworming historyDeworming history
Collected at least Collected at least twice (8-10 and 12-14 twice (8-10 and 12-14 weeks of age; some at weeks of age; some at 16-18 weeks) on 15 16-18 weeks) on 15 lambs per sire:lambs per sire: DateDate WeightWeight Body condition scoreBody condition score FAMACHAFAMACHA Vigor scoreVigor score Fecal egg countFecal egg count
ResultsResults Identified several rams that APPEAR to Identified several rams that APPEAR to
show greater ability to transmit show greater ability to transmit parasite resistance to offspringparasite resistance to offspring
Management practices had major Management practices had major impactimpact
Time of lambingTime of lambing Pasture managementPasture management
All farms able to identify potential All farms able to identify potential replacement ewe and ram lambsreplacement ewe and ram lambs
Avg Ram A
Lamb ID DOBSex Born /
RearedFEC
7/12/06
7161 2/18/06 R 2/2 18507162 2/18/06 E 2/2 4507163 2/20/06 R 2/2 3007164 2/20/06 E 2/2 6507165 2/21/06 R 2/2 4507166 2/21/06 R 2/2 4507167 2/22/06 R 1/1 9507168 2/24/06 R 2/2 90007169 2/24/06 E 2/2 6507170 2/25/06 E 2/2 13007171 2/25/06 E 2/2 95507172 2/27/06 E 2/1 2507173 2/27/06 E 2/2 2007174 2/27/06 E 2/2 101507178 3/6/06 E 1/1 300
2433
Avg = 1605 epg
Avg = 3280 epg
Avg Ram A
Adequate Numbers Are Adequate Numbers Are Necessary for Valid ComparisonsNecessary for Valid Comparisons
Farm #1 Farm #1 All dewormed 7/20/06All dewormed 7/20/06 Rotated across previously Rotated across previously
grazed pasturesgrazed pastures
Farm #2 All dewormed 7/16/06 Moved to clean pasture
every week
Lamb ID Sire ID FAMACHA FEC Lamb ID Sire ID FAMACHA FEC
603 A 3 300 11 B 2 0612 A 3 0 14 B 2 0613 A 1 250 46 B 1 0616 A 3 1100 5 B 1 50638 A 2 300 10 B 1 0639 A 3 500 49 B 1 0640 A 3 3450 6 B 3 50641 A 3 1800 24 B 2 0645 A 3 250 29 B 2 150646 A 3 3150 3 B 2 0
Management Example: Management Example: Time of LambingTime of Lambing
At 2At 2ndnd collection (13 weeks collection (13 weeks of age):of age):
older and heavier lambs older and heavier lambs had lower FEC. had lower FEC.
a 10 day increase in lamb a 10 day increase in lamb age resulted in 21% age resulted in 21% decrease in FEC. decrease in FEC.
a 10 pound increase in a 10 pound increase in lamb weight resulted in lamb weight resulted in 18% decrease in FEC.18% decrease in FEC.
Offspring of Sire A probably show more parasite resistance than Sire B.
But, dams of Sire B offspring mainly ewes lambing as yearlings – confounds results.
Lamb ID Sire IDAge of Dam
FEC6/12/06
FEC7/12/06
7162 A 2 150 4507167 A 3 1150 9507170 A 2 1600 13007171 A 2 7450 95507172 A 3 300 2507173 A 2 1100 2007174 A 2 2050 101507175 A 3 1100 10507176 A 3 250 5507177 A 3 3050 5007178 A 4 100 300
A 1664 2295
7179 B 1 2350 82507180 B 1 100 5507181 B 1 2000 7007182 B 1 200 1507183 B 1 3000 139007184 B 2 650 26007185 B 2 1800 7507186 B 1 4500 81507187 B 2 4450 10900
Selecting Parasite Selecting Parasite Resistant Service Sires Resistant Service Sires
Based on FECBased on FEC Be sure there is a challengeBe sure there is a challenge
Group average FEC of 1000 epg or higherGroup average FEC of 1000 epg or higher
Compare adequate numbers Compare adequate numbers 15-25 animals15-25 animals Compare at least 2 siresCompare at least 2 sires
Compare apples to apples:Compare apples to apples: Same ageSame age Similar managementSimilar management Similar dam age, litter size, etc.Similar dam age, litter size, etc.
Calculate average FEC of all lambs from each sire Calculate average FEC of all lambs from each sire
Choose sire with lowest average progeny FECChoose sire with lowest average progeny FEC
Compare apples to apples:Compare apples to apples: Same ageSame age Similar managementSimilar management Similar dam age, litter size, etc.Similar dam age, litter size, etc.
Choose lambs from sire with lowest average Choose lambs from sire with lowest average progeny FEC if more than 1 sireprogeny FEC if more than 1 sire
Choose animals with lowest FECs in groupChoose animals with lowest FECs in group At least 2 FECs at different dates increases accuracyAt least 2 FECs at different dates increases accuracy
Replacement Animal SelectionReplacement Animal SelectionLamb ID Sex
Birth /Rearing
Sire IDAge of Dam
FEC6/12/06
FEC7/12/06
7162 E 2/2 A 2 150 4507167 R 1/1 A 3 1150 9507170 E 2/2 A 2 1600 13007171 E 2/2 A 2 7450 95507172 E 2/1 A 3 300 2507173 E 2/2 A 2 1100 2007174 E 2/2 A 2 2050 101507175 E 3/3 A 3 1100 10507176 E 3/3 A 3 250 5507177 E 3/3 A 3 3050 5007178 E 1/1 A 4 100 300
A Avg 1664 2295
7179 R 2/2 B 1 2350 82507180 E 2/2 B 1 100 5507181 E 1/1 B 1 2000 7007182 E 1/1 B 1 200 1507183 E 1/1 B 1 3000 139007184 R 2/2 B 2 650 26007185 E 2/2 B 2 1800 7507186 E 1/1 B 1 4500 81507187 R 1/1 B 2 4450 10900
B Avg 2117 5106
SARE Project Conclusions:SARE Project Conclusions:Dr. Notter’s CommentsDr. Notter’s Comments
Selection favoring low FEC will be effective in increasing Selection favoring low FEC will be effective in increasing parasite resistance in Katahdin flocks. Heritability parasite resistance in Katahdin flocks. Heritability estimate = 0.52.estimate = 0.52.
Age at measurement likely less important than level of Age at measurement likely less important than level of infection at time of data collection.infection at time of data collection.
Selection on FAMACHA scores on older lambs effective, Selection on FAMACHA scores on older lambs effective, but likely to produce considerably slower changes than but likely to produce considerably slower changes than direct FEC measurement and selection.direct FEC measurement and selection.
A combination of recording FAMACHA scores to A combination of recording FAMACHA scores to monitor levels of parasite infection and recording monitor levels of parasite infection and recording FEC as selection tool may be optimal strategy to FEC as selection tool may be optimal strategy to improve genetic resistance to internal parasites.improve genetic resistance to internal parasites.
Avoid Single Trait Selection: We Avoid Single Trait Selection: We select for both low FEC and high select for both low FEC and high
productivityproductivity2005 Ewe Production / Fecal Egg Count
0
500
1,000
1,500
2,000
2,500
0 20 40 60 80 100 120 140 160 180
Pounds of Lamb Weaned(Adjusted Weights)
Av
era
ge
FE
C D
uri
ng
La
cta
tio
n
(Tw)
(Tw)
(Tw)
(Tw)
(Tw)
(Tw)
(Tr)
(S)
(S)
(S)
(Tw) (Tr)
(Tw)
(Tw)
(Tw)
(S)(S)
Ew e Lambs show n in red; Number of lambs raised ( )
ResourcesResources Southern Consortium for Small Ruminant Southern Consortium for Small Ruminant
Parasite ControlParasite Control http://www.scsrpc.orghttp://www.scsrpc.org
Maryland Small Ruminant PageMaryland Small Ruminant Page http://www.sheepandgoat.comhttp://www.sheepandgoat.com
ATTRA ATTRA (Appropriate Technology Transfer for Rural Areas)(Appropriate Technology Transfer for Rural Areas)
http://attra.orghttp://attra.org
Katahdin Hair Sheep InternationalKatahdin Hair Sheep International http:// khsi.orghttp:// khsi.org