Johnes Disease Update Steve Hendrick DVM DVSc Thursday

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: n Ontario n n n Atlantic Provinces n n n Cows: 2. 2%, Herds: 10% (Tremblay et al. , 2001) Cows: 7% (Mc. Nab et al. , 1991) Cows: 16% (Mc. Kenna et al. , 2004) Cows: 1. 6%, Herds: 17% (Van. Leeuwen et al. , 2001) Alberta n Cows: 7% (Sorensen et al. , 2003)

Prevalence: 50 randomly selected dairy herds: Milk Cow-level: 1. 7% Herd-level*: 18% Serum 2. 6% 30% * 2 or more positive cows per herd

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

Production: n Milk Production n Decreased: n n n Increased: n n n Nordlund et al. , 1996; Sweeney et al. , 1994 Mc. Nab et al. , 1991; Benedictus et al. , 1987 Culling n Increased risk n Wilson et al. , 1993

305 -day Milk Production: Variable: fecal culture positive milk ELISA positive serum ELISA positive Estimate SE: P-value: -548 -464 -173 193 188 154 <0. 01* 0. 26 (kg) Controlled for: parity, DIM, SCC-LS, and herd. * significant at p<0. 05

Culling: Variable: fecal culture positive milk ELISA positive serum ELISA positive Hazard Ratio: 3. 2 2. 3 1. 7 P-value: <0. 01* 0. 05* Controlled for: parity, DIM, milk production, pregnancy status, SCC-LS, and herd. * significant at p<0. 05

Partial Budget: n Assumptions: n n 100 cow dairy herd 10% fecal culture positive n n n 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: n n non-infected cows: $200 Infected cows: $0

Partial Budget: n Culling: 1. Non-infected herd: n 2. 30% of 100 cows = 30 cows Infected herd: n n n 30% of 90 non-shedding cows = 27 cows 36 cows 90% of 10 fecal positive cows = 9 cows n 6 additional culls n 6 x $1, 200 per heifer = $7, 200 extra for replacements n 9 infected culls: n 9 x $200 opportunity cost = $1, 800 Sub-total = $9, 000

Partial Budget: n Milk Production: n 550 kg (5. 5 HL) of lost milk for each infected cow (fecal culture) n n 10 cows x 5. 5 HL/cow x $60/HL = $3, 300 Total: n n $9, 000 + $3, 300 = $12, 300 equates to $123 per cow ($100 USD) n n $100 -200 USD per cow (Ott et al. , 1999) $49 per cow (Chi et al, 2002)

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

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

Johne’s Risk Factors: Variable: OR: P-value: Previous Diagnosis of Johne’s Disease Milk production (10 BCA points) 3. 4 0. 9 <0. 01 Rumensin given to cows within last five yearsa 0. 5 0. 04 0. 5 0. 03 Background: Pre-weaning Heifer Calves: Calves kept in hutches a evaluated both premix and controlled-release capsule usage

Risk Factors: In herds with a history of Johne’s disease: Variable: Background: Milk production (10 BCA points) Calving Pen: Calves removed >1 hr Springing Heifer Cleanliness: - Manure on hip, belly & udder OR: P-value: 0. 9 <0. 01 2. 7 0. 05 1. 9 0. 07

Risk Factors: In herds with no prior history of Johne’s disease: Variable: a Background: Purchase replacement cattle Rumensin given to cows within last five yearsa OR: P-value: 3. 2 0. 05 0. 3 <0. 01 0. 2 <0. 01 Pre-weaning Heifer Calves: Calves kept in hutches a evaluated both premix and controlled-release capsule usage

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

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

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

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

Questions?