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 Selecting Sheep for Parasite Resistance Questions & Answers

Courtesy of William Shulaw, DVM, MS

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

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

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

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

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

Misty Oaks Farm - 2004 Our current grant had it’s start in work we did on our farm through a Warner grant in 2004, and then an individual SARE producer grant in 2005. In both years we worked with Dr. Shulaw, and selectively dewormed and monitored fecal egg counts weekly through the spring and summer. At the end of the first summer, we looked at the average FEC of lambs from each sire, and saw some drastic differences. As you can see, lambs from this ram (Ram C) had some pretty high counts, and every one required deworming. This ram (Ram A) on the other hand, had lambs with consistently low counts, and none ever required deworming. This gave us the idea to identify sires with ability to pass on increased resistance to parasites. Several other Katahdin breeders were also interested, which led us to the 2006 SARE farmer/rancher grant.

Participants Total of 456 lambs and 31 rams in project 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 Here is the list of farmers on the grant. There were 10 of us from three states: Ohio (7) Missouri (2) and Pennsylvania (1) Nine producers raise Katahdin Hair Sheep; one used Katahdin ram on mixed Dorset ewes Flock sizes range from 11 to 900+ ewes 7 Registered and 3 commercial flocks We ended up with a total of 456 lambs and 31 rams in the project! Total of 456 lambs and 31 rams in project

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

Our Collaborators New Cooperator William Shulaw, DVM, MS Extension Veterinarian, Beef/Sheep Ohio State University Charles Parker, PhD Professor Emeritus, Dept of Animal Science 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

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) Our objectives on this grant were first to identify rams with the ability to sire lambs with increased parasite resistance. Although we all raise Katahdins and are forage based, there are many differences in management. This became more apparent as we went along.

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 to Hemonchus contortus only How many people are familiar with FAMACHA? FAMACHA is a way of determining the level of parasite-induced anemia in sheep and lambs by looking at the mucus membranes of the lower eyelid. It was developed in South Africa. Courtesy of William Shulaw, DVM, MS

FAMACHA – How it Works

Fecal egg counts (FEC) using McMaster Technique 1 egg = 50 epg

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

Detailed Record Keeping 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

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

Adequate Numbers Are Necessary for Valid Comparisons Avg = 1605 epg Avg = 3280 epg Avg Ram A In any type of selection, you really need enough animals to make valid comparisons. 10 is the minimum, and 15 is ideal. Using more than 15 doesn’t seem to affect accuracy. Avg Ram A

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

Management Example: Pasture Conditions Can Change Quickly

Management Example: Nutrition Singles in both cases have lower counts, probably at least in part because they had more milk The triplets tend to have higher counts than singles or twins. A twin out of a 4 year old (#612) has lower counts than a twin out of a yearling (#646 or #616) Ram lambs seem to have more challenge than ewe lambs. The same principle applies to ewes, especially during lactation.

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. Dr. Notter found that at 13 weeks of age, for every 10 lb increase in a lamb’s weight there was an associated decline in FEC of 21%!! Remember, this is in Katahdin lambs. Wool breeds typically develop resistance somewhat later.

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.

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

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

Replacement Animal Selection Note that #7172 and #7178 are low, but are raised as single – assume better nutrition. #7173 is a twin born and raised and shows evidence of self cure. I like that. Also, #7177 appears better than #7176 – self cure versus slow increase. What about Ram B? (#7185 might be my choice – 2/2,shows evidence of self cure. #7182 and #7181 might be ok – both singles out of yearlings)

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.

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

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