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

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

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

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

Milk

BHB

A, m

mol

/L

Serum BHBA, mmol/L

Blood BHBA vs. Milk BHBA

Accuracy = 62%

y = 0.16 + 1.2R² = 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

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