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Diagnosing and Monitoring Ketosis in Dairy Herds

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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

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Diagnosing and Monitoring Ketosis in Dairy Herds

  1. 1. Diagnosing and Monitoring Ketosis in Dairy Herds Garrett R. Oetzel, DVM, MS School of Veterinary Medicine Food Animal Production Medicine Section
  2. 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. 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. 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. 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. 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. 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. 8. Blood BHBA Upper Threshold  Cows ≥ 3.0 mmol/L should show clinical signs  What are the clinical signs?
  9. 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. 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. 11. Measures of Blood BHBA  Researchers use laboratory tests on blood serum  On-farm ketosis testing must be cowside
  12. 12. Cowside Tests for Ketosis  May use blood, urine, or milk  May measure different ketone bodies  BHBA  AcAc (acetoacetate)  acetone
  13. 13. Cowside Testing for Ketosis  Sweet smell of breath  acetone, other compounds  only about 50% sensitive
  14. 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. 15. Urine Ketones  Ketostix test strip  about $0.20 each  have to stimulate urination  dip and read within 10 seconds
  16. 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. 17. Interpreting Urine Ketones  Consider “small” (15 mg/dL) or greater to be ketosis  Modest sensitivity and specificity  80% sensitive  95% specific
  18. 18. Other Cowside Ketone Tests - Milk  Powders or tablets  nitroprusside reaction  35% sensitive  98% specific  Not recommended as sole test
  19. 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. 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. 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. 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. 23. Nova Biomedical Meters  Nova Vet  bovine calibration  $3.20 per strip  Nova Max Plus  human version  $2.00 per strip
  24. 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. 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. 26. Using the Meter  Insert strip into meter before applying blood  Keep the meter and the strips warm  enzymatic reactions are temperature sensitive
  27. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 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. 38. Questions?

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