Comparisons of available on-farm tests for monitoring ketosis in dairy cattle
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EmailA guide to selecting the right ketosis monitoring tool for your needs.
During the transition period, cows rapidly mobilize body fat, which increases the risk of developing metabolic diseases including ketosis, fatty liver, and displaced abomasum. Producers should confirm the diagnosis of ketosis before proceeding with treatment. There are now a variety of inexpensive on-farm tests available to confirm the presence of ketones for both routine herd level monitoring and individual diagnosis.
Ketosis is characterized by the accumulation of the ketone bodies betahydroxybutrate (BHBA), acetoacetate (AcAc), and acetone. The standard test for the diagnosis of ketosis is serum BHBA concentrations above14.4 mg/dL(1400 µM/L) as measured in a diagnostic lab (Oetzel, 2004). The five available cowside tests measure either AcAC or BHBA in urine, milk, or whole blood.
There are currently five available on-farm tests for ketones, summarized by sample type and cost below (adapted from Townsend, Tri-State Dairy Nutrition Proceedings, 2011).
|
Product |
Sample Type |
Ketone measured |
Cost |
|
KetoCheck powder |
milk or urine |
Acetoacetone |
~ $0.28/test |
|
KetoStix |
urine |
Acetoacetone |
~$0.24 |
|
KetoTest |
milk |
BHBA |
~$2.00 |
|
PortaBHB |
milk |
BHBA |
~$1.75/strip |
|
Precision Xtra |
blood |
BHBA |
~1.30/strip ~$15 – $20 for meter |
Which test should you use? Your selection depends on what your goal is. Are you trying to estimate herd level ketosis or confirm diagnosis of ketosis in an individual animal? The five on-farm tests available vary in the sensitivity and specificity monitoring. Sensitivity is a measurement of the actual positives the test can correctly determine as compared to the standard. Specificity is a measurement of the actual negatives the test can correctly determine. In this case, the standard is the laboratory determination of serum levels above 14.4 mg/dL.
For example, KetoCheck powder (Great States Animal Health, St. Joseph, MO) was shown to be 41% sensitive and 99% specific for diagnosing subclinical cases of ketosis when compared to the standard (Carrier et al, 2004). Because of the high specificity, this would be a good choice to confirm diagnosis in an individual cow because it will rarely give a false positive. However, if using KetoCheck to assess herd level ketosis, many subclinical ketotic cows would be falsely identified negative due to the low sensitivity.
Ketostix (Bayer Corp. Diagnostics Division, Tarrytown, NY) has a sensitivity of 78% and a specificity of 96% when compared to a serum standard of 14.4 ml/dL. If using the cutpoint of 100 µmol/L on the colorimetric scale, Keto Test (Sanwa Kagaku Kenkyusho Co., LTD,. Nagoya, Japan – distributed by Elanco Animal Health) has shown 73%-80% sensitivity and 76% and 96% specificity (Geishauser et al., 2000; Carrier et al., 2004). PortaBHB (PortaCheck, Inc., Moorestown, NJ) consists of test strips similar to Keto Test and has shown similar sensitivity and specificity to Keto Test (Townsend, Tri-State Dairy Nutrition Proceedings, 2011). The Precision Xtra™ meter using the Precision Xtra™ Blood Ketone test strips (Abbott Laboratories, Abbott Park, IL) has shown excellent accuracy at 91% sensitivity and 94% specificity (Oetzel and McGuirk, 2009).
If the goal is to determine if an individual cow has ketosis, recommended tests would be the KetoCheck, Ketostix, or the Precision Xtra™ meter. If the goal is to determine herd level ketosis, such as during routine fresh cow monitoring, then using the KetoStix, KetoTest, the PortaBHB test, or the Precision Xtra™ meter would be good options. An acceptable protocol for monitoring fresh cow incidence of ketosis is to test 12 or more cows. If more than 10% of the cows have ketone levels above the accepted standard of 14.4 ml/dL, the group is considered to have a ketosis issue (Oetzel, 2004).
In summary, new advancements of on farm technology to monitor ketosis has made the provided a variety of choices in to assist in making diagnosis of ketosis easier and quicker.
