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Johne’s Disease Update:

Johne’s Disease Update:. Steve Hendrick, DVM, DVSc Thursday, April 14 th , 2005. Outline:. Johne’s Disease Background Impact on Production Risk Factors Conclusions. Johne’s Disease:. Johne’s Disease:. Ontario Cows: 2.2%, Herds: 10% ( Tremblay et al., 2001)

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Johne’s Disease Update:

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  1. Johne’s Disease Update: Steve Hendrick, DVM, DVSc Thursday, April 14th, 2005

  2. Outline: • Johne’s Disease • Background • Impact on Production • Risk Factors • Conclusions

  3. Johne’s Disease:

  4. Johne’s Disease: • Ontario • Cows: 2.2%, Herds: 10% (Tremblay et al., 2001) • Cows: 7% (McNab et al., 1991) • Atlantic Provinces • Cows: 16% (McKenna et al., 2004) • Cows: 1.6%, Herds: 17% (VanLeeuwen et al., 2001) • Alberta • Cows: 7% (Sorensen et al., 2003)

  5. Prevalence: 50 randomly selected dairy herds: MilkSerum Cow-level: 1.7% 2.6% Herd-level*: 18% 30% * 2 or more positive cows per herd

  6. Johne’s Disease: • Production limiting disease • Milk production, longevity, fertility, milk quality • International trade barriers • Crohn’s Disease ???

  7. Production: • Milk Production • Decreased: • Nordlund et al., 1996; • Sweeney et al., 1994 • Increased: • McNab et al., 1991; • Benedictus et al., 1987 • Culling • Increased risk • Wilson et al., 1993

  8. 305-day Milk Production: Controlled for: parity, DIM, SCC-LS, and herd. * significant at p<0.05

  9. Culling: Controlled for: parity, DIM, milk production, pregnancy status, SCC-LS, and herd. * significant at p<0.05

  10. Partial Budget: • Assumptions: • 100 cow dairy herd • 10% fecal culture positive • 10 infected cows + 90 non-shedding cows • annual culling rate of 30% • average milk price = $60/HL • cost of a replacement heifer = $1,200 • slaughter value: • non-infected cows: $200 • Infected cows: $0

  11. Partial Budget: • Culling: • Non-infected herd: • 30% of 100 cows = 30 cows • Infected herd: • 30% of 90 non-shedding cows = 27 cows • 90% of 10 fecal positive cows = 9 cows • 6 additional culls • 6 x $1,200 per heifer = $7,200 extra for replacements • 9 infected culls: • 9 x $200 opportunity cost = $1,800 • Sub-total = $9,000 36 cows

  12. Partial Budget: • Milk Production: • 550 kg (5.5 HL) of lost milk for each infected cow (fecal culture) • 10 cows x 5.5 HL/cow x $60/HL = $3,300 • Total: • $9,000 + $3,300 = $12,300 • equates to $123 per cow ($100 USD) • $100-200 USD per cow (Ott et al., 1999) • $49 per cow (Chi et al, 2002)

  13. Other Johne’s Frustrations: • Treatment: • None are efficacious and cost-effective • Diagnosis: • Sub-clinical infections: • difficult to identify - all tests lack sensitivity • Prevention and Control: • What are the important control points?

  14. Johne’s Risk Factors: • Calf housing and feeding • Calving pen cleanliness • Herd size and purchased replacement cattle • History of clinical disease • Housing of periparturient cows • Soil type or pH • Access to wildlife • Cow nutrition and water sources

  15. Johne’s Risk Factors: aevaluated both premix and controlled-release capsule usage

  16. Risk Factors: In herds with a history of Johne’s disease:

  17. Risk Factors: In herds with no prior history of Johne’s disease: aevaluated both premix and controlled-release capsule usage

  18. Take Home Message: • Prevalence of Johne’s disease in Ontario: • Higher than previously reported • 1 out of 3 farms are infected

  19. Take Home Message: • Production Impacts: • Milk: loss of 150 to 550 kg (2-6%) • Culling: removed 2 to 3 times faster • Partial Budget: ~$120 per cow in the herd

  20. Take Home Message: • Prevention: • avoid purchase of replacement cattle • Control: • maternity pen: • reduce time in maternity pen by calf • heifer rearing: • housing of heifer calves • springing heifer cleanliness • monensin sodium usage ???

  21. Acknowledgements: • Ontario Dairy Producers • Veterinary Practitioners • Advisory Committee: • Dr. Todd Duffield, Dr. Dave Kelton, Dr. Kerry Lissemore, Dr. Ken Leslie, Dr. Marie Archambault • Technical Assistants

  22. Questions?

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