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• In my personal experience, I have never diagnosed a Suffolk or Hampshire sheep with OPP though I have had testimony from producers that have purchased positively infected black-faced rams. • Certain breeds seem to have a higher rate of infection. Note the breed alliance list at the end of this paper. Diagnosis of OPP Diagnosis of this disease is best provided through finding antibodies in the blood (serology). Because the virus is slow growing and hides in the cells, the sheep will be slow to make antibodies to it. The tests available are not perfect but, if used properly, will help in eradication. Diagnosis with a positive serological test in a clinically affected sheep is only a start. Testing to determine who may be infected and spreading the virus is the tricky part. There are two commonly used serological tests available. • AGID (agar gel immunodiffusion) - Very specific and rare to get false positives. - Only about 75% sensitive. The sheep has been infected a while before seroconverting. - May give false negatives early in infection – or suspects. - Difficult test to read so the lab technician reading it is very important. - Use a lab that runs them regularly and has a record of accuracy. • cELISA (competitive enzyme-linked immunoabsorbent assay) - More sensitive test therefore can detect antibodies earlier in infection (2 weeks?) - Less specific due to sensitivity. Other factors can trigger false positives. - Laboratory differences confuse results. • Other tests available - PCR (polymerase chain reaction) reads DNA - Postmortem ID of virus Control of OPP If you decide to embark on an eradication program for your flock, testing every sheep over 6 months of age will tell you what your incidence is. With this information, you can make decisions whether to cull and retest over a series of 6 month intervals or keep separate flocks and orphan raise your replacements. Don’t forget the rams. There are many factors that need to be considered in these decisions – do you have genetics that you want to save, do you have time to orphan lambs, facilities to keep positive and negative flocks separate? • > 50% positive, probably orphan the females, maybe some ram lambs for breeding. Need to catch the wet lambs prior to nursing, preferably before they hit the ground. Leave the wether lambs and feeder ewe lambs on the positive dams. The lambs need to be raised in 28
separate facilities and tested at 4 months (?) and before lambing as yearlings to verify negative status. • < 50% positive, consider culling and retesting every 6 months. Three 100% negative tests are comforting. Testing a percentage of older ewes annually can be validating. The choice to eradicate this virus will also: • Give you the chance to choose other diseases to eradicate – Johne’s and caseous lymphadenitis for example. • Breeding stock will have more value (remember scrapie and the genotyping requests?). • Save feed costs. • Allow your flock to perform to its full potential – you can truly evaluate your genetics. What Have We Learned About OPP? • This is a very prevalent virus that is silently passed from sheep to sheep within a flock and between flocks through purchases of both ewes and rams. • Through the NAHMS study, we see that the incidence of OPP estimated 20 years ago was correct. • Flock owners (and veterinarians) all over the United States are ignorant about this virus • Many shepherds accept the signs of the disease as normal – would they be amazed at how productive their flocks would be without the virus? • It is possible and economically prudent to eradicate this virus from a flock – especially a sheep dairy flock. • CAE virus in goats is not known (?) to infect sheep but could confuse testing results in an eradication program if goat colostrum/milk is used from CAE positive goats. • Possible to pass the virus from infected sheep in fair and show environments. Breed Association Alliances • American Border Leicester Association • Finnsheep Breeders Association, Inc • Icelandic Sheep Breeders of North America • Jacob Sheep Conservancy • North American Clun Forest Association • Texel Sheep Breeders Society Ovine Progressive Pneumonia Concerned Sheep Breeder’s Society (OPPCSBS) • Started in 1990 when a group of frustrated shepherds wanted more information and understanding of this disease they were trying to eradicate from their flocks. • Over 100 members from 27 states, 3 provinces. Flocks range from 10 to >1000 sheep. • Newsletter and website (www.oppsociety.org) includes general information and guidelines for OPP testing, a membership directory and a Veterinary referral list. • Videos describing blood collection techniques and handling • Educational materials available for distribution at events 29
Page 1 and 2: Proceedings of the 12 th Annual GRE
Page 3 and 4: Symposium Organizing Committee Yves
Page 5 and 6: Table of Contents (cont.) SHEPHERD
Page 7 and 8: Program of Events (cont.) Friday, N
Page 9 and 10: Gold: Sponsors Babcock Institute fo
Page 11 and 12: SHEEP DAIRY FARM ECONOMIC ANALYSIS
Page 13 and 14: 3) Recordkeeping a) Degrees of deta
Page 15 and 16: Out of this allocation, the Dairy B
Page 17 and 18: The original plan for Uplands was t
Page 19 and 20: Cheese As previously mentioned, Ple
Page 21 and 22: ORGANIC SHEEP DAIRY: MARKETS AND PR
Page 23 and 24: products that, especially combined
Page 25 and 26: Organic Milk Production Requirement
Page 27 and 28: To become certified, you must first
Page 29 and 30: ATTRA- the National Sustainable Agr
Page 31 and 32: 1.2. The average western Pyrenees d
Page 33 and 34: During the last 15 years, the avera
Page 35 and 36: The growth of the market of Pyrenee
Page 37: them tested for OPP using the cElis
Page 41 and 42: • Neoplastic tumors Treatment •
Page 43 and 44: STRATEGIC CONTROL OF GASTRO-INTESTI
Page 45 and 46: C. Intestinal cestode parasites (ta
Page 47 and 48: Strategic Timing of Treatment Phase
Page 49 and 50: 1.2. IMI is the main factor influen
Page 51 and 52: 1.3. Use of SCC in order to detect
Page 53 and 54: within-day fluctuation (SCC level a
Page 55 and 56: expensive. But it is necessary to b
Page 57 and 58: The influence of high SCC on cheese
Page 59 and 60: Figure 9. Contribution to bulk tank
Page 61 and 62: Regarding the dynamics of the infec
Page 63 and 64: Figure 11. Evolution of the average
Page 65 and 66: Lafi S.Q. 2005. Use of somatic cell
Page 67 and 68: (Penning et al., 1988). Another stu
Page 69 and 70: Pre-grazing herbage mass (kg DM/ha)
Page 71 and 72: Table 2: Average test day milk prod
Page 73 and 74: Figure 4: Average test day milk fat
Page 75 and 76: lactation ewes (1.66 vs. 1.50 kg/d,
Page 77 and 78: Figure 6: Average change in body we
Page 79 and 80: esults, so an average pasture CP va
Page 81 and 82: Pulina, G. 2002. Dairy Sheep Feedin
Page 83 and 84: light treatments, when all ewes wer
Page 85 and 86: percentage protein (AgSource Milk L
Page 87 and 88: the difference was significant on o
Page 89 and 90:
kg), fat (+ 3.0 kg), protein (+ 0.9
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Auchtung, T. L., A. G. Rius, P. E.
Page 93 and 94:
site of a small settlement for seve
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Gonyou, HW and Stookey, JM. 1983. U
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SHEPHERD’S DAIRY Kim Curtis Ansel
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Breeds As I stated above, we starte
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Summary ARTISAN SHEEP MILK CHEESE J
Page 103 and 104:
ACCURACY OF THE PORTASCC® MILK TES
Page 105 and 106:
Correlation between laboratory resu
Page 107 and 108:
CLOVER DALE SHEEP DAIRY John Henry
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CARR VALLEY CHEESE - WISCONSIN’S
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101
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We We We Welcome Welcome You You Yo
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Hudson Valley Camemberts Pure Sheep
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107
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N681 Rollwood Road Antigo, WI 54409
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