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What to do with daily milk data - advanced epidemiology

What to do with daily milk data - advanced epidemiology. R Shephard 1 and MA Stevenson 2 1 Gippsland Herd Improvement 2 Foster St Maffra, Victoria, Australia 2 EpiCentre, IVABS, Massey University, Palmerston North, New Zealand. Roadmap. Lactation curves Shewart charts

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What to do with daily milk data - advanced epidemiology

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  1. What to do with daily milk data - advanced epidemiology R Shephard1 and MA Stevenson2 1 Gippsland Herd Improvement 2 Foster St Maffra, Victoria, Australia 2 EpiCentre, IVABS, Massey University, Palmerston North, New Zealand

  2. Roadmap • Lactation curves • Shewart charts • Individual somatic cell count frequency histograms • Individual somatic cell count scatter plots

  3. Lactation curves • Herd test data • rank cows in order of productive merit • dry off and culling decisions • somatic cell counts  dry cow therapy decisions

  4. Lactation curves • Lactation curves •  herd test milk volumevs days in milk at date of herd test • an additional (objective) way to assess a herd’s feeding program

  5. Lactation curves

  6. Good producers (abortions?) Peak yield Persistency Crook? Non-seasonally calving, pasture + concentrate fed herd: Kiama NSW

  7. Non-seasonally calving, pasture + concentrate fed herd: Kiama NSW Peak yield = 28.5 litres at 50 DIM  0.04 litres per day   1.2 litres per month  1.2 28.5 ~ 4.2% per month

  8. Seasonally calving, pasture fed herd: Palmerston North

  9. Seasonally calving, pasture fed herd: Palmerston North Peak yield = 25.7 litres at 50 DIM  0.07 litres per day   2.1 litres per month  2.1  25.7 ~ 8.2% per month

  10. Seasonally calving, pasture fed herd: Masterton

  11. Seasonally calving, pasture fed herd: Masterton Peak yield = 15.4 litres at 50 DIM  0.03 litres per day   0.9 litres per month  0.9  15.4 ~ 5.8% per month

  12. Non-seasonally calving, pasture + concentrate fed herd: Kangaloon NSW Peak yield = 26.9 litres at 50 DIM  0.03 litres per day   0.9 litres per month  0.9  26.9 ~ 3.3% per month

  13. Lactation curves

  14. Lactation curves • Fat to protein ratio vs DIM

  15. Low protein relative to fat - low energy intake? Low fat relative to protein - insufficient dietary fibre? Seasonally calving, pasture fed herd: Palmerston North

  16. Seasonally calving, pasture fed herd: Masterton

  17. Low protein relative to fat - low energy intake? Low fat relative to protein - insufficient dietary fibre? Seasonally calving, pasture fed herd: Palmerston North

  18. Seasonally calving, pasture fed herd: Palmerston North Seasonally calving, pasture fed herd: Masterton

  19. Roadmap • Lactation curves • Shewart charts • Individual somatic cell count frequency histograms • Individual somatic cell count scatter plots

  20. Shewart charts • Common to monitor aspects of herd performance as a function of time: • bulk milk tank volume • successful inseminations • bulk milk tank somatic cell counts • How many abnormal values do we need to accumulate before blowing the whistle?

  21. Non-seasonally calving, pasture + concentrate fed herd: Moss Vale NSW

  22. Non-seasonally calving, pasture + concentrate fed herd: Moss Vale NSW Define what is ‘normal’ and an acceptable level of variability:

  23. Non-seasonally calving, pasture + concentrate fed herd: Moss Vale NSW Define what is ‘normal’ and an acceptable level of variability:

  24. Non-seasonally calving, pasture + concentrate fed herd: Moss Vale NSW Test 1: a single point outside of control limits Test 2: 3 out of 4 consecutive points closer to the control limit than to the centre line Test 3: 8 or more successive points on one side of the centre line

  25. Roadmap • Lactation curves • Shewart charts • Individual somatic cell count frequency histograms • Individual somatic cell count scatter plots

  26. ICSCC frequency histograms • Bin ICSCCs: • 0 - 100,000 cells/mL • 100,000 - 200,000 cells/mL • etc • Count up the number that fall into each group and plot as bar charts • See Ryan (1991)

  27. Good mastitis control: high numbers in 0 - 100,000 cells/mL category low numbers in 500,000 - 1,000,000 cells/mL category

  28. Poor mastitis control: lower numbers in 0 - 100,000 cells/mL category higher numbers in 500,000 - 1,000,000 cells/mL category

  29. Ineffective teat dip: large numbers 100,000 - 200,000 cells/mL category A.bovis  udder ‘irritant’

  30. ICSCC frequency histograms • How can we use ICSCC histograms? • effective way to monitor responses to suggested mastitis controls • ICSCC frequency histograms change relatively quickly after implementation of a mastitis control program • BMSCCs, in contrast, change more slowly

  31. Non-seasonally calving, pasture + concentrate fed herd: Moss Vale NSW

  32. Start of control Non-seasonally calving, pasture + concentrate fed herd: Moss Vale NSW

  33. Roadmap • Lactation curves • Shewart charts • Individual somatic cell count frequency histograms • Individual somatic cell count scatter plots

  34. ICSCC scatter plots • Clarify patterns of subclinical mastitis from one herd test to the next • take two [consecutive] herd tests • plot first herd test ICSCC value (x axis) vs second herd test ICSCC value (y axis)

  35. Non-seasonally calving, pasture + concentrate fed herd: Kiama NSW New infections Chronics Clear Cured

  36. Seasonally calving, pasture fed herd: Palmerston North New infections Chronics Clear Cured

  37. Seasonally calving, pasture fed herd: Palmerston North New infections Chronics Clear Cured

  38. Scatter plots - continued • Loeffler et al. (1999) • study of 9369 lactations evaluated effect of milk components on dairy cow fertility • increase in fat-protein ratio a possible risk for reproductive failure

  39. Seasonally calving, pasture fed herd: Palmerston North Low - High High - High Low - Low High - Low

  40. Seasonally calving, pasture fed herd: Masterton Low - High High - High Low - Low High - Low

  41. Lactation curves … quantify herd production characteristics Roadmap

  42. Lactation curves … Shewart charts … quantify herd production characteristics help to decide when to blow the whistle Roadmap

  43. Lactation curves … Shewart charts … ICSCC frequency histograms … quantify herd production characteristics help to decide when to blow the whistle monitor response to controls Roadmap

  44. Lactation curves … Shewart charts … ICSCC frequency histograms … ICSCC scatter plots … quantify herd production characteristics help to decide when to blow the whistle monitor response to controls identify infection patterns Roadmap

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