Dr. Gary Oetzel presented this material for DAIReXNET on January 5th, 2016. To see more about this and other webinars, please visit our archived webinar page at http://bit.ly/1wb83YV

1. Diagnosing and
Monitoring Ketosis
in Dairy Herds
Garrett R. Oetzel, DVM, MS
School of Veterinary Medicine
Food Animal Production Medicine Section

2. Introduction to Ketosis
 Remarkable metabolic
shift after calving
 poor adaptive response to negative
energy balance leads to ketosis
 excessive mobilization of body fat
relative to available carbohydrates

3. Why All the Fuss About Ketosis?
 Ketosis is the most common metabolic disease
in dairy cattle
 20 to 60% incidence
 5 to 30% prevalence

4.  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

5. 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

6. 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

7. 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

8. Blood BHBA Upper Threshold
 Cows ≥ 3.0 mmol/L
should show
clinical signs
 What are the
clinical signs?

9. 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

10. 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

11. Measures of Blood BHBA
 Researchers use
laboratory tests on
blood serum
 On-farm ketosis
testing must be
cowside

12. Cowside Tests for Ketosis
 May use blood, urine, or milk
 May measure different ketone bodies
 BHBA
 AcAc (acetoacetate)
 acetone

13. Cowside Testing for Ketosis
 Sweet smell of breath
 acetone, other
compounds
 only about 50%
sensitive

14. GS (+) GS (-)
Test (+)
TP (True
Positive)
FP (False
Positive)
TP + FP
Test (-)
FN (False
Negative)
TN (True
Negative)
TN + FN
TP + FN TN + FP Total
Sensi =
TP / (TP + FN)
Spec =
TN / (TN + FP)

15. Urine Ketones
 Ketostix test strip
 about $0.20 each
 have to stimulate
urination
 dip and read within
10 seconds

16. 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

17. Interpreting Urine Ketones
 Consider “small”
(15 mg/dL) or
greater
to be ketosis
 Modest sensitivity
and specificity
 80% sensitive
 95% specific

18. Other Cowside Ketone Tests - Milk
 Powders or tablets
 nitroprusside reaction
 35% sensitive
 98% specific
 Not recommended as sole test

19. 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

20. 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

21. Other Cowside Ketone Tests - Blood
 Abbott Precision Xtra™
human hand-held
system
 Consider ≥1.2 mmol/L
as ketosis
 >90% sensitive
 >95% specific

22. 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

23. Nova Biomedical Meters
 Nova Vet
 bovine calibration
 $3.20 per strip
 Nova Max Plus
 human version
 $2.00 per strip

24. 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%

25. Blood Sample Collection – Tail Vein
 NOT the milk vein
 Use 22 or 25 gauge
needle with
1 or 3 ml syringe
 No special restraint

26. Using the Meter
 Insert strip into meter
before applying blood
 Keep the meter and
the strips warm
 enzymatic reactions
are temperature
sensitive

27. 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

28. y = 0.16 + 1.2
R² = 0.09
0.00
0.50
1.00
1.50
2.00
2.50
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
MilkFat:ProteinRatio
Serum BHBA, mmol/L
Blood BHBA vs. Milk Fat:Protein Ratio
Accuracy = 68%

29. 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

30. y = 0.16 + 1.2
R² = 0.09
0.00
0.10
0.20
0.30
0.40
0.50
0.60
0.70
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
MilkBHBA,mmol/L
Serum BHBA, mmol/L
Blood BHBA vs. Milk BHBA
Accuracy = 62%

31. y = 0.16 + 1.2
R² = 0.09
0.00
0.50
1.00
1.50
2.00
2.50
3.00
3.50
4.00
0.0 1.0 2.0 3.0 4.0 5.0 6.0 7.0
MilkBHBA,mmol/L
Serum BHBA, mmol/L
Blood BHBA vs. Milk Acetone
Accuracy = 82%

32. 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

33. 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)

34. 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

35. 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

36. 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

37. 0%
10%
20%
30%
40%
50%
60%
70%
80%
7/1/2013
7/15/2013
7/29/2013
8/12/2013
8/26/2013
9/9/2013
9/23/2013
10/7/2013
10/21/2013
11/4/2013
11/18/2013
12/2/2013
12/16/2013
12/30/2013
1/13/2014
1/27/2014
2/10/2014
2/24/2014
3/10/2014
3/24/2014
4/7/2014
4/21/2014
5/5/2014
5/19/2014
6/2/2014
6/16/2014
6/30/2014
7/14/2014
7/28/2014
PercentbloodBHBA>=1.2mmol/L
Date of BHBA Testing
Summary of Herd BHBA Testing
(7/13 to 7/14; results pooled by 2-week intervals)

38. Questions?