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2006 SARE Group Farmer/Rancher Grant

2006 SARE Group Farmer/Rancher Grant. Selecting Sheep for Parasite Resistance SARE Project Number: FNC05-583. Kathy Bielek Misty Oaks Farm 1130 Kimber Road Wooster, OH 44691 330-264-5281 bielek@bright.net. Outline. The Parasite Problem Background 2006 SARE Producer Grant

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2006 SARE Group Farmer/Rancher Grant

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  1. 2006 SARE Group Farmer/Rancher Grant Selecting Sheep for Parasite Resistance SARE Project Number: FNC05-583 Kathy Bielek Misty Oaks Farm 1130 Kimber Road Wooster, OH 44691 330-264-5281 bielek@bright.net

  2. Outline • The Parasite Problem • Background • 2006 SARE Producer Grant • Selecting Sheep for Parasite Resistance • Questions & Answers

  3. Courtesy of William Shulaw, DVM, MS

  4. The Parasite Problem • Parasites affect the health and productivity of sheep • Reduced lamb growth • Potential death of lambs and ewes • Require expensive chemical dewormers • Most susceptible are lambs & lactating ewes • Parasites are developing resistance to dewormers

  5. RESISTANCE SELECTION IN ADULT WORMS TREATMENT Courtesy of William Shulaw, DVM, MS

  6. Why Selection Works • Parasite numbers not evenly distributed among all animals in flock • Roughly 20% of animals harbor 80% of parasites • Treating only those 20% helps avoid developing parasites resistant to dewormers • Identifying and selecting less susceptible replacement animals will help increase flock’s resistance to parasites over time

  7. Fall 2000 103,546,200 eggs per day for just 46 sheep Just 10 (21%) of the lambs excreted 77% of the eggs !!

  8. 1850 epg 150 epg 650 epg 600 epg 2450 epg 150 epg 17,300 epg

  9. Misty Oaks Farm - 2004

  10. Participants • Jeff & Kathy Bielek - Misty Oaks Farm - Ohio • David Coplen - Birch Cove Farm - Missouri • Doug & Mary Emrick - Lazydae Farm - Ohio • Richard Gilbert - Mossy Dell Farm - Ohio • Naomi & Dean Hawkins - Green Pastures Farm - Ohio • Sue & Dave Ingram - DSI Katahdins - Missouri • Leah Miller - Bluebird Hill Farm - Ohio • Jim Orr - Orr Farm - Ohio • Bill Pope - Ohio • Donna & Doug Stoneback - Wade Jean Farm - Pennsylvania Total of 456 lambs and 31 rams in project

  11. Katahdins: The Low Maintenance Meat Sheep • Excellent mothers • No shearing • Medium size • 200% lamb crop • Single purpose: Meat • Natural parasite resistance

  12. Our Collaborators • William Shulaw, DVM, MS Extension Veterinarian, Beef/Sheep Ohio State University • Charles Parker, PhD Professor Emeritus, Dept of Animal Science Ohio State University New Cooperator • David Notter, PhD Professor of Animal Science Virginia Tech • Dr. Notter directs the National Sheep Improvement Program (NSIP) Genetic Evaluation Center at Virginia Tech

  13. Objectives of The Grant • Identify rams with ability to transmit parasite resistance to offspring • Compare effect of different management systems • Investigate method to identify potential replacement seed stock Tools • FAMACHA • Body Condition Scoring (BCS) • Vigor Scoring • Fecal Egg Counts (FEC)

  14. The FAMACHA© System • Compare eye color chart with color of mucous membranes of sheep • 1 – not anemic • 5 -- severely anemic • Eye color is an indirect measure of the worm burden – applies toHemonchus contortus only Courtesy of William Shulaw, DVM, MS

  15. FAMACHA – How it Works

  16. Fecal egg counts (FEC) using McMaster Technique1 egg = 50 epg

  17. Method • All lambs identified by sire • All lambs managed together in single group on each farm • FEC, FAMACHA & BCS done twice: at 8-10 weeks & 12-14 weeks • No changes made to management of each farm

  18. Collected on all 456 lambs: Lamb ID Date of birth Sex Birth type & rearing Birth weight Sire ID Dam ID Age of Dam Deworming history Collected at least twice (8-10 and 12-14 weeks of age; some at 16-18 weeks) on 15 lambs per sire: Date Weight Body condition score FAMACHA Vigor score Fecal egg count Detailed Record Keeping

  19. Results • Identified several rams that APPEAR to show greater ability to transmit parasite resistance to offspring • Management practices had major impact • Time of lambing • Pasture management • All farms able to identify potential replacement ewe and ram lambs

  20. Avg = 1605 epg Avg = 3280 epg Avg Ram A Adequate Numbers Are Necessary for Valid Comparisons Avg Ram A

  21. Management Example: Pasture Management Matters • Farm #2 • All dewormed 7/16/06 • Moved to clean pasture every week • Farm #1 • All dewormed 7/20/06 • Rotated across previously grazed pastures

  22. Management Example: Pasture Conditions Can Change Quickly

  23. Management Example: Nutrition

  24. Management Example: Time of Lambing At 2nd collection (13 weeks of age): • older and heavier lambs had lower FEC. • a 10 day increase in lamb age resulted in 21% decrease in FEC. • a 10 pound increase in lamb weight resulted in 18% decrease in FEC.

  25. Probable Sire Differences • 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.

  26. Selecting Parasite Resistant Service Sires Based on FEC • Be sure there is a challenge • Group average FEC of 1000 epg or higher • Compare adequate numbers • 15-25 animals • Compare at least 2 sires • Compare apples to apples: • Same age • Similar management • Similar dam age, litter size, etc. • Calculate average FEC of all lambs from each sire • Choose sire with lowest average progeny FEC

  27. Selecting Parasite Resistant Replacement Animals • Be sure there is a challenge • Group average FEC of 1000 epg or higher • Compare adequate numbers • 15-25 animals • Compare apples to apples: • Same age • Similar management • Similar dam age, litter size, etc. • Choose lambs from sire with lowest average progeny FEC if more than 1 sire • Choose animals with lowest FECs in group • At least 2 FECs at different dates increases accuracy

  28. Replacement Animal Selection

  29. SARE Project Conclusions:Dr. Notter’s Comments • Selection favoring low FEC will be effective in increasing parasite resistance in Katahdin flocks. Heritability estimate = 0.52. • Age at measurement likely less important than level of infection at time of data collection. • Selection on FAMACHA scores on older lambs effective, but likely to produce considerably slower changes than direct FEC measurement and selection. • A combination of recording FAMACHA scores to monitor levels of parasite infection and recording FEC as selection tool may be optimal strategy to improve genetic resistance to internal parasites.

  30. Avoid Single Trait Selection: We select for both low FEC and high productivity

  31. Resources • Southern Consortium for Small Ruminant Parasite Control • http://www.scsrpc.org • Maryland Small Ruminant Page • http://www.sheepandgoat.com • ATTRA (Appropriate Technology Transfer for Rural Areas) • http://attra.org • Katahdin Hair Sheep International • http:// khsi.org

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