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
On National Teacher Day, meet the 2024-25 Kenan Fellows
Diagnosing and Monitoring Ketosis in Dairy Herds
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
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
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
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
Third image is urine and the powder. Illustrates that urine is an important excretion route for AcAc – it is concentrated in urine. AcAc is excreted in milk, but it roughly equilibrates with blood only (no concentration). This also shows the potential for urine to give false positives when it is mixed with powder ('too much' contact). Best to use the urine strips – dip and read.
Preliminary results - Nova Vet isn't worth it.
Based on cutpoint of >=0.08 mmol/L
Based on cutpoint of >=1.3 mmol/L
And this is what fueled our collaborative research project. We knew that there had to be a better way to use the available data to develop a herd ketosis monitoring tool.