materials reviewed by national johne's working group / johne's disease committee / usaha...
Post on 18-Dec-2015
215 Views
Preview:
TRANSCRIPT
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
Steven Ott and Scott Wells USDA and University of Minnesota
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
Steven Ott and Scott Wells USDA and University of Minnesota
Economic impact of herd Johne’s status
NAHMS Dairy 96 Study
Herd status % of herds $ per cow
Negative 78 0
Positive 22 -$97
Steven Ott and Scott Wells USDA and University of Minnesota
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
Steven Ott and Scott Wells USDA and University of Minnesota
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)
Steven Ott and Scott Wells USDA and University of Minnesota
Risk factors identified for the control of Johne’s
disease by NAHMS Dairy ’96 Study
Steven Ott and Scott Wells USDA and University of Minnesota
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
Steven Ott and Scott Wells USDA and University of Minnesota
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
Steven Ott and Scott Wells USDA and University of Minnesota
Risk factors for Johne’s disease
NAHMS Dairy 96 Study
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%
Steven Ott and Scott Wells USDA and University of Minnesota
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
Steven Ott and Scott Wells USDA and University of Minnesota
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
Steven Ott and Scott Wells USDA and University of Minnesota
Johne’s disease herd risk factors
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 --
Steven Ott and Scott Wells USDA and University of Minnesota
Percent of operations by use of type of maternity housing
facilitiesNAHMS 1996
0102030405060708090
Multiple cow Separate from lactating cow
<100 cows 100-199 cows 200 or more cows
Steven Ott and Scott Wells USDA and University of Minnesota
Percent of operations using calving area as hospital area
for sick cowsNAHMS 1996
0
10
20
30
40
50
60
<100 cows 100-199 cows 200 or more cows
Steven Ott and Scott Wells USDA and University of Minnesota
Johne’s disease herd risk factors
NAHMS Dairy 96 Study
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
Steven Ott and Scott Wells USDA and University of Minnesota
Johne’s disease herd risk factors
NAHMS Dairy 96 Study
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 --
Steven Ott and Scott Wells USDA and University of Minnesota
Collins et al, www.johnes.org
Steven Ott and Scott Wells USDA and University of Minnesota
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
Steven Ott and Scott Wells USDA and University of Minnesota
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
Steven Ott and Scott Wells USDA and University of Minnesota
Comparison of Johne’s disease herd status by familiarity and previous
diagnosisNAHMS Dairy 96 Study
Unfamiliar Familiar andno previousdiagnosis
Familiar andpreviousdiagnosis
Use manureequip forfeedingheifers
21.8 23.9 23.8
Calving areaused for sickcows
50.9 58.5 57.0
Steven Ott and Scott Wells USDA and University of Minnesota
Comparison of Johne’s disease herd status by familiarity and previous
diagnosisNAHMS Dairy 96 Study
Unfamiliar Familiar andno previousdiagnosis
Familiar andpreviousdiagnosis
25% or morecows born offoperation
26 25 39
Multiple cowmaternity area
27 31 37
Steven Ott and Scott Wells USDA and University of Minnesota
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
Steven Ott and Scott Wells USDA and University of Minnesota
Questions
Steven Ott and Scott Wells USDA and University of Minnesota
top related