Diagnosing and Monitoring Ketosis in Dairy Herds
Transcript of Diagnosing and Monitoring Ketosis in Dairy Herds
Diagnosing and Monitoring
Ketosis in Dairy Herds
Garrett R. Oetzel, DVM, MSSchool of Veterinary Medicine
Food Animal Production Medicine Section
Introduction to Ketosis
Remarkable metabolicshift after calving poor adaptive response to negative
energy balance leads to ketosis excessive mobilization of body fat
relative to available carbohydrates
Why All the Fuss About Ketosis? Ketosis is the most common metabolic disease
in dairy cattle 20 to 60% incidence 5 to 30% prevalence
Incidence Total number of new cases Requires repeat sampling
Prevalence How many cases present on one day Spot sampling Prevalence x 2 to 2.5 = Incidence
Ketosis Prevalence vs. Incidence
Why All the Fuss About Ketosis? Decreased milk production
3 to 7% loss reported actually worse than this
Increase risk of DA 3 to 19X greater risk
Increased risk of culling in first 30 d 3X greater risk
Decreased reproductive performance 1.2 to 1.7X less likely to conceive at 1st breeding less impact if doing ovulation synchronization
Measures of Ketosis Blood beta-hydroxybutyric acid (BHBA) is the
de facto standard stable compound works for serum, plasma, or whole blood easy to quantify (even cowside)
Allows us to quantify ketosis using a lower and an upper threshold
Blood BHBA Lower Threshold 1.2 mmol/L is the most common
lower threshold depends on the outcome
(milk, disease, removal) depends on days in milk when tested
Range of reported values 1.0 to 1.4 mmol/L no real value in switching thresholds -
just use 1.2 mmol/L
Blood BHBA Upper Threshold Cows ≥ 3.0 mmol/L
should show clinical signs
What are the clinical signs?
Clinical Signs of Ketosis Decreased milk yield Depression (dull appearance) Decreased rumen motility Normal rectal temperature Better appetite for hay than
silage or grains All of these signs are
subjective and often missed
Categories of Ketosis Based on BHBA 'Subclinical' ketosis
1.2 to 2.9 mmol/L 'Clinical' ketosis
≥ 3.0 mmol/L or 'ketosis'
(hyperketonemia) ≥ 1.2 mmol/L
Measures of Blood BHBA Researchers use
laboratory tests on blood serum
On-farm ketosis testing must be cowside
Cowside Tests for Ketosis May use blood, urine, or milk May measure different ketone bodies
BHBA AcAc (acetoacetate) acetone
Cowside Testing for Ketosis Sweet smell of breath
acetone, other compounds
only about 50% sensitive
GS (+) GS (-)
Test (+) TP (True Positive)
FP (False Positive)
TP + FP
Test (-) FN (False Negative)
TN (True Negative)
TN + FN
TP + FN TN + FP TotalSensi =
TP / (TP + FN)Spec =
TN / (TN + FP)
Urine Ketones Ketostix test strip
about $0.20 each have to stimulate
urination dip and read within
10 seconds
Urine Ketones 40 to 60% will urinate
catheters or vaginal exams are impractical
touching strip to vaginal walls is inaccurate
Need a plan for cows that do not urinate
Interpreting Urine Ketones Consider “small”
(15 mg/dL) or greaterto be ketosis
Modest sensitivity and specificity 80% sensitive 95% specific
Other Cowside Ketone Tests - Milk Powders or tablets
nitroprusside reaction 35% sensitive 98% specific
Not recommended as sole test
Other Cowside Ketone Tests - Milk Ketotest™ test strip
~$2.50 per test dip and read 60
seconds later use 100 umol/l
cut-point 83% sensitive 82% specific
Other Cowside Ketone Tests - Milk
PortaBHB™ test strip ~$2.50 per test dip and read 60
seconds later use 100 umol/l
cut-point 89% sensitive 80% specific
Other Cowside Ketone Tests - Blood Abbott Precision Xtra™
human hand-held system
Consider ≥1.2 mmol/L as ketosis >90% sensitive >95% specific
Precision Xtra™ Meter Useful for:
cow-level diagnosis herd-level monitoring herd-level research
No longer available at the veterinary price of $1.40 per strip human price is $4 to $6
per strip Canadian sources are
about $2.50 per strip
Nova Biomedical Meters Nova Vet
bovine calibration $3.20 per strip
Nova Max Plus human version $2.00 per strip
Nova Biomedical Meters Strip errors
keep blood off the top of the strip
let blood aspirate up into the 3 sample wells
meter is 'upside-down' Modest sensitivity and
specificity 80 to 90%
Blood Sample Collection – Tail Vein NOT the milk vein Use 22 or 25 gauge
needle with 1 or 3 ml syringe
No special restraint
Using the Meter Insert strip into meter
before applying blood Keep the meter and
the strips warm enzymatic reactions
are temperature sensitive
DHI-Based Ketosis Testing Initial approach was milk fat:protein ratios
ketosis does increase milk fat and decrease milk protein
fat:protein ratios ≥1.4 are suggestive of ketosis Used only for very general herd inference
not a cow-level test
y = 0.16 + 1.2R² = 0.09
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0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
Milk
Fat
:Pro
tein
Rati
o
Serum BHBA, mmol/L
Blood BHBA vs. Milk Fat:Protein Ratio
Accuracy = 68%
DHI-Based Ketosis Testing Next approach was milk ketone analysis
milk BHBA and milk acetone available with new milk testing capabilities no agreement on cutpoints modest accuracy
y = 0.16 + 1.2R² = 0.09
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Milk
BHB
A, m
mol
/L
Serum BHBA, mmol/L
Blood BHBA vs. Milk BHBA
Accuracy = 62%
y = 0.16 + 1.2R² = 0.09
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0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
Milk
BHB
A, m
mol
/L
Serum BHBA, mmol/L
Blood BHBA vs. Milk Acetone
Accuracy = 82%
DHI-Based Ketosis Testing Most recent approach - combine test day
information with milk analysis results uses all available data greatly improves the prediction of blood BHBA
Now available through AgSource as KetoMonitor
KetoMonitor Development Collected blood samples on the day of milk
test at AgSource member farms 550 cows and heifers 10 Holstein farms (2 Jersey farms)
Laboratory BHBA assay was the gold standard Basic cow data (lactation number, days in milk) Milk sample analysis (fat, protein, BHBA,
acetone, MUN)
Analysis Statistical analysis using multiple
regression models Specific models for different categories:
1st vs. 2+ lactation 5 to 11 vs. 12 to 20 DIM Holsteins vs. Jerseys
Animal tested
1st Lact
5 to 11 DIM
Model
R2 = 0.74
12 to 20 DIM
Model
R2 = 0.66
2+ Lact
5 to 11 DIM
Model
R2 = 0.57
12 to 20 DIM
Model
R2 = 0.67
Accuracy: 88% 83%96% 97%
KetoMonitor Groups
Herd Level Ketosis Testing Implement some form of testing Testing designs are flexible
knowing your prevalence allows clients to optimize testing and treatment strategies
topic of a future seminar (Dr. McArt) Herd prevalence is not static over time
7/1/20137/15/20137/29/20138/12/20138/26/20139/9/20139/23/201310/7/201310/21/201311/4/201311/18/201312/2/201312/16/201312/30/20131/13/20141/27/20142/10/20142/24/20143/10/20143/24/20144/7/20144/21/20145/5/20145/19/20146/2/20146/16/20146/30/20147/14/20147/28/2014
0%
10%
20%
30%
40%
50%
60%
70%
80%
Summary of Herd BHBA Testing (7/13 to 7/14; results pooled by 2-week intervals)
Date of BHBA Testing
Perc
ent b
lood
BHB
A >=
1.2
mm
ol/L
Questions?
www.vetmed.wisc.edu/dms/fapm