Transcript Ketone and NEFA testing as diagnostic tools n assessing

Ketone and NEFA testing
as diagnostic tools in
assessing transition dairy
cows
Stephen LeBlanc
OABP/OABA meeting
April 14, 2005
Monitoring Programs for
Transition Cows
1.
Monitor Current Transition Cow Program
– HERD LEVEL
–
–
Track success and compliance with existing
program
Early detection of problems
–
Early treatment to prevent clinical disease
2. Monitor for Subclinical Disease
- INDIVIDUAL LEVEL
•
Helps to quantify problems and direct
investigation
Options for Monitoring or
Investigating
• Clinical disease incidence
• Milk production
• DMI
– Why doesn’t it get done??
– Group average; distribution within group
– Target > 12 kg DMI average in close-up
(heifers & cows; 3 weeks before due)
– Fresh group
• Metabolic tests
Daily Dry Matter Intake
Around Calving
CALVING
*
Propionate
AA
Glycerol
Gluconeogenesis
Glucose
NEFA
Completely
oxidized 
energy
BHB
Incompletely
oxidized 
ketones
Acetoacetate
Acetone
Re-esterified
 triglyceride
Fetus
Mammary
gland
Stored in
liver
Exported in VLDL
Propionate
AA
Gluconeogenesis
Glucose
NEFA
Completely
oxidized 
energy
Unsuccessful
response to
NEB –
Ketosis and
Fatty liver
BHB
Incompletely
oxidized 
ketones
Acetoacetate
Acetone
Re-esterified
 triglyceride
Fetus
Mammary
gland
Stored in
liver 
Exported in VLDL
Typical patterns of DMI
and NEFA
Overton/Burhans, 2001
Associations with health
and performance
• Pre-partum NEFA associated
with:
– ~ 4X increased risk of LDA
(Cameron et al, 1998; LeBlanc et al, 2005)
– ~ 1.5X increased risk of RP
(Dyk, 1995; LeBlanc et al, 2004)
– 2 – 3 X increased risk of subclinical ketosis
(Osborne, 2003; Gooijer et al, 2004)
Incidence of Subclinical
Ketosis
Median time to diagnosis of
clinical ketosis = 11 DIM
35
30
25
Incidence of
subclinical
ketosis (%)
20
15
10
5
0
0
1
2
3
4
5
6
7
Weeks from Calving
8
9
10
Duffield, 2000
35
Serum BHB
30
M ilk ketones
25
% of Cow s
w ith
Subclinical
Ketosis
20
15
10
Prevalence
of Subclinical
Ketosis
5
0
-4
-2
0
2
4
W eeks From Calving
Duffield et al 1998
6
8
10
Oetzel, 2003
Clinical ketosis treatment rate
is a poor estimate of ketosis
Clinical Ketosis
10
9
8
7
6
5
4
3
2
1
0
60
40
20
Herd
13
17
1
2
12
11
14
15
0
8
% Subclinical Ketosis
80
% Clinical Ketosis Incidence
SCK 1400 BHBA
(Duffield et al 1998)
Associations with health
and performance
• BHB (subclinical ketosis) in early
lactation is associated with:
– 4-8X increased risk of LDA
(Geishauser, 2000; LeBlanc et al, 2005)
– Decreased milk production
(Duffield, 2000)
– Increased severity of mastitis
(Suriyasathaporn et al, 2000)
– 50% decrease in pregnancy at first AI
(Walsh et al, 2004)
.2
.3
.4
Effect of subclinical ketosis in
week 2 on CR at 1st AI
.1
(Walsh et al, 2004)
0
1000
2000
Week 2 BHBA
3000
4000
Cow-side tests for ketosis
(relative to serum BHB ≥1400 µmol/L)
Milk
Keto-Test
Urine
Ketostix (read at 5
• 100 µmol/L
– Sensitivity = 83%
– Specificity = 82%
• 200 µmol/L
– Sensitivity = 54%
– Specificity = 94%
Oetzel, 2004
• Powder lacks
sensitivity
seconds)
• “small” (15µmol/L)
– Sensitivity = 79%
– Specificity = 96%
Carrier et al, 2004
• Acetest tablet lacks
specificity
Subclinical Ketosis Monitoring
Programs
(True Prevalence = 20%)
Test
PV +
PV-
Apparent
Prevalence
Keto-Test
(100 umol/L)
62%
93%
23%
Keto-Test
(200 umol/L)
80%
87%
11%
Ketocheck (Milk)
90%
86%
8%
Acetest(Urine)
38%
100%
53%
Sampling logistics
• In a herd with 50 to 1000 cows, if a
prevalence of “positive” tests
– e.g. NEFA ≥ 0.5 or BHB ≥ 1400
• And ≥ 10% is the threshold of interest
• And you wish to be 75% confident of
detecting this level of problem, then…
• 13 samples are required
• Oetzel proposes using 12 samples for
NEFA and BHB blood testing for
investigations
Metabolic Predictors of LDA
•
•
•
•
1184 animals in 20 herds
Weekly visit by technician
Same day, same time (AM)
Cows enrolled 4 - 10 d prior to
expected calving
• Sampled weekly until the week after
calving (Total of 2 - 4 samples)
LeBlanc et al, 2005
Serum NEFA (mEq/L)
2.0
Cows without DA (n = 1078)
Cows with DA (n = 53)
1.5
1.0
0.5
0.0
-20
-15
-10
-5
Days from calving
0
5
10
LeBlanc et al, 2005
Serum hydroxybutyrate (mol/L)
3500
3000
Cows without DA (n = 1078)
Cows with DA (n = 53)
2500
2000
1500
1000
500
0
-20
-15
-10
-5
Days from calving
0
5
10
LeBlanc et al, 2005
Prepartum DA model
• Among all variables measured in last
week before calving:
OR 95% CI
P
NEFA  0.5 mEq/L 3.5 1.9 – 7.1 .0001
Sensitivity = 64% Specificity = 66%
LeBlanc et al, 2005
Simple Association of
NEFA 4-10 d before
DUE with LDA
NEFA OR
Se
Sp
LR
 0.3
2.3
63
56
1.4
 0.4
2.6
50
72
1.8
 0.5
4.1
46
82
2.6
 0.6
3.0
30
89
2.6
 0.8
2.6
17
93
2.5
 1.0
4.1
15
96
3.8
LeBlanc et al, 2005
Simple Association of
NEFA 4-10 d before DUE
with LDA
NEFA OR OR* Se
Se* Sp
Sp* LR
LR*
 0.3
2.3 2.6
63
61
56
61
1.4
1.6
 0.4
2.6 2.9
50
47
72
77
1.8
2.0
 0.5
4.1 5.1
46
43
82
87
2.6 3.3
 0.6
3.0 3.7
30
26
89
92
2.6 3.2
 0.8
2.6 3.0
17
12
93
96
2.5 3.1
 1.0
4.1 5.1
15
12
96
98
3.8 5.2
LeBlanc
et al, 2005
* Excluding cows within 2 days of actual
calving
Postpartum DA model
Variable
OR
95% CI
P
RP
1.7
1.1 – 2.7
.01
Metritis
4.8
2.0 – 11.2 .0003
BHB per 100 mol/L *
1.08
1.06 – 1.1
.0001
NEFA per 1.0 mEq/L *
2.4
1.4 – 4.3
.002
Season, parity, MF, twins all NS
Minimum significant cut-points in the model:
BHB  1000 mol/L ; NEFA  0.6 mEq/L
LeBlanc et al, 2005
Postpartum Simple
Associations with DA
Test
NEFA
BHB
Cutpoint
OR
Se
Sp
LR
0.6
4.8
86
43
1.5
0.8
3.9
68
64
1.9
1.0
4.8
56
79
2.6
1000
6.3
69
74
2.6
1200
8.0
63
82
3.5
1400
8.0
53
88
4.3
LeBlanc et al, 2005
Postpartum Simple
Associations with DA
Test Cutpoint
OR
Se
Sp
LR
Milk
BHB
100
2.8
64
62
1.7
200
3.4
48
80
2.4
LeBlanc et al, 2005
Sample handling
• Serum (red top) or plasma (purple top)
• Avoid hemolysis
• Ideal: keep chilled, separate within a few
hours, ship chilled to arrive at lab in 1-2
days
• Serum can be frozen for at least 1 month
• What you could get away with: delay of < 24
h to separate; serum at room temp for < 24
h or in fridge for < 3 days
(Stokol & Nydam, 2004)
Monitoring Energy Metabolism
in Transition Cows
• Pre-Calving -
NEFA
• Post-Calving - Ketones
– Routine monitoring (milk or urine)
Monitoring Energy Metabolism
in Transition Cows
• Helps to direct investigation
– What is the problem?
– Where/when is the problem?
• Rarely answers “WHY?”
– Need to look further and test
hypotheses
Evaluation of a Rapid, OnSite Serum NEFA Test
•
•
•
•
•
10 Guelph-area farms
Prepartum blood sample
(-7 to –4 days)
Harvested serum and aliquoted
Measure NEFA concentrations:
– Animal Health Laboratory
(Hitachi 911 analyzer)
– DVM NEFA
Gooijer et al, ICPD 2004
Correlation between tests
Pearson’s r = 0.89
1.400
1.200
DVM NEFA
1.000
0.800
0.600
R2 = 0.80
0.400
0.200
0.000
0.0
0.2
0.4
0.6
0.8
1.0
1.2
AHL NEFA
Gooijer et al, ICPD 2004
1.4
Test Characteristics of DVM
NEFA
(Gold Standard = AHL > 0.4 mEq/L)
AHL NEFA
DVM
NEFA
 0.5
<0.5
>0.4
133
7
140
 0.4
25
185
210
158
Sensitivity = 84%
192 350
Specificity = 96%
Gooijer et al, ICPD 2004
Maintaining Peripartum
DMI
• Fresh feed daily
• Adequate bunk space
(>60 cm)
• > 100 ft2/cow of pack
• < 100% stocking
• Separate heifer
groups
• Moderate BCS (3.5)
• Adaptation to new
rations (3-4 weeks)
• Adequate eNDF
• Minimize group/pen
changes
• Heat abatement
– THI > 72
– T > 27 C
• Free choice water
• 0.5 – 0.75% BW in
concentrates
• 60:40
Forage:concentrate
• Rumensin CRC