Materials reviewed by National Johne's Working Group / Johne's Disease Committee / USAHA 2003 Reduced Revenues and Risk Factors Associated with Johne’s

Materials reviewed by National Johne's Working Group / Johne's Disease Committee / USAHA 2003

Reduced Revenues and Risk Factors

Associated with Johne’s in Dairy Herds NAHMS

Steven Ott DVM Scott J Wells DVM

CEAH USDA-APHIS-VS

Economic impact of Johne’s disease

NAHMS Dairy 96 Study

• Use of herd-level management data• Based on changes in adjusted

revenue on a per cow inventory basis• Adjust for herd size, region, DHIA,

intensive grazing, bST use, bulk tank SCC, days dry, % Holstein, registered herd, familiarity with Johne’s disease, change in cow inventory

Steven Ott and Scott Wells USDA and University of Minnesota

Adjusted revenueNAHMS Dairy 96 Study

• Gross revenue– Value of milk production– Value of calves at birth– Cull cow sales– Cows sold to other producers

• Minus cow replacement costs


Economic impact of herd Johne’s status

NAHMS Dairy 96 StudyHerd status % culls with

clinical signs % of herds $ per cow

Negative 0% 52 0

1-10% 22 -$42

10% or more 4 -$195

Positive <10% 15 -$61

10% or more 7 -$245


Economic impact of herd Johne’s status


Herd status % of herds $ per cow

Negative 78 0

Positive 22 -$97


Johne’s disease cost comparisons

Prices standardizedStudy $ per cow

NAHMS Dairy 96 $22

Meyer and Hall, 1994 $24

Whitlock and others, 1985 $20

Abbas and others, 1983 $21

Chiodini and Van Kruiningen, 1986 $26


Summary of Johne’s economic impact

• Economic impact is a function of Johne’s herd status and percent of cull cows with clinical signs of Johne’s disease

• Costs are not trivial; $245 per cow compared to returns of $243 per cow over cash expenses for middle 50% of U.S. dairy producers (USDA-ERS)


Risk factors identified for the control of Johne’s

disease by NAHMS Dairy ’96 Study


Hurdles to overcome in control of Johne’s disease• Long incubation period• Delayed detection and low test

sensitivity• Lack of familiarity by producers• Poorly defined economic losses• Lack of consistent control programs• Regulatory and ethical problems with

testing


Johne’s disease control measures

1. Screen purchased cattle to avoid introduction of infection

2. Identify infected cattle and remove from herd to prevent further transmission

3. Prevent calves from ingesting organism (from manure, milk, or colostrum)

4. Decrease contamination of environment to decrease exposure to organism


Risk factors for Johne’s disease


Risk factor Population attributable risk

% milk cows born off operation 33%

Multiple cow maternity housing 15%

Multiple calf preweaned housing 17%

Herd size 14%

Region 43%


Johne’s disease herd risk factors

NAHMS Dairy 96 StudyRisk factor Odds ratio 95% confidence

interval% milk cows bornoff operation None 1.0 --

1-24% 1.6 1.0-2.7

25% or more 2.1 1.3-3.5


Percent of dairy operations that introduced cattle in previous year

NAHMS 1996

0

10

20

30

40

50

60

70

Bred dairyheifers

Lactatingdairy cows

Bulls(weaned)

Any dairy orbeef cattle

<100 cows 100-199 cows 200 or more cows



NAHMS Dairy 96 StudyRisk factor Odds ratio 95% confidenceinterval

Multiple cow maternity housing

Yes 1.5 1.0-2.3

No 1.0 --

Multiple calf preweaned housing

Yes 1.5 1.0-2.3

No 1.0 --


Percent of operations by use of type of maternity housing

facilitiesNAHMS 1996

0102030405060708090

Multiple cow Separate from lactating cow



Percent of operations using calving area as hospital area

for sick cowsNAHMS 1996

0

10

20

30

40

50

60





Risk factor Odds ratio 95% confidenceinterval

Herd size

30-49 cows 1.0 --

50-99 1.2 0.7-2.1

100-299 1.7 1.0-3.0

300 or more 4.6 2.3-9.2




Risk factor Odds ratio 95% confidenceinterval

Region

West 0.9 0.4-1.8

Midwest 2.0 1.0-3.7

Northeast 1.2 0.6-2.4

Southeast 1.0 --


Collins et al, www.johnes.org


Comparison of familiarity and previous diagnosis with Johne’s disease herd

statusNAHMS Dairy 96 Study

Herd familiarity and previous diagnosis

% herds Johne’s disease test-positive

Unfamiliar 13.2

Familiar and no previous diagnosis

18.6

Familiar and previous diagnosis

47.3


111111

Comparison of Johne’s disease herd status by familiarity and previous

diagnosisNAHMS Dairy 96 Study

Unfamiliar Familiar andno previousdiagnosis

Familiar andpreviousdiagnosis

% herdsJohne’s testpositive

13.2 18.6 47.3






Use manureequip forfeedingheifers

21.8 23.9 23.8

Calving areaused for sickcows

50.9 58.5 57.0






25% or morecows born offoperation

26 25 39

Multiple cowmaternity area

27 31 37


Probability of purchasing one or more Johne's infected cattle

0.00

0.10

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0 20 40 60 80 100

Number of cattle purchased

Pro

ba

bili

ty o

f b

uyi

ng

at

lea

st

on

e

infe

cte

d a

nim

al

From Johne's infected herd

From general population

Testing from generalpopulation

From level 1 herd

From level 2 herd

From level 3 herd


Questions


Documents

Materials reviewed by National Johne's Working Group / Johne's Disease Committee / USAHA 2003 Reduced Revenues and Risk Factors Associated with Johne’s