trends in noncompliance with milk quality standards for dairy herd improvement herds in the united...
TRANSCRIPT
Trends in Noncompliance with Milk Quality Standards for Dairy Herd Improvement Herds in the United States
H. D. Norman*, J. R. Wright
Animal Improvement Programs Laboratory, Agricultural Research Service, USDA, Beltsville, MD 20705-2350
INTRODUCTION Most countries have an upper limit for
somatic cell count (SCC) because it is considered an indicator of milk quality.
The current US SCC limit remains at 750,000 cells/mL; however the European Union (EU) standard (400,000 cells/mL) is being imposed on many herds exporting dairy products to Europe.
Several US states already have, or are in the process of lowering their SCC limits below the national standard (CA, ID, MT, NV, OR, WA).
Examine the trend in frequency of herd non-compliance for SCC based on current and alternative standards
OBJECTIVE
DATA & METHODS
DATA:
Approximately 95% of Dairy Herd Improvement (DHI) herds are enrolled in somatic cell score (SCS) testing
Used monthly test day SCS from herds enrolled in DHI programs for three 12-mo periods: November 2009 to October 2010, November 2010 to October 2011, and November 2011 to October 2012
Each cow SCS converted to SCC:
SCC = 2(SCS-3) (100,000)
Individual cow SCC weighted by her test day milk yield to produce test-day SCC for the herd
EDITS:
≥ 10 cows for all test days
15 to 26 tests in each 12-mo period
Noncompliance was calculated for SCC levels of 750,000, 500,000 and 400,000 cells/mL for both US and EU methods
RESULTS (cont.)
RESULTS
RESULTS (cont.)
•US DHI Test Day SCC (All Breeds) 2000-2012
•Percentage of US DHI herd-tests noncompliant by SCC level
US method (frequency)
EU method (geometric)
(1000’s of cells/mL)750 500 400 750 500 400
Nov 2009-Oct 2010
0.9 6.2 14.1 0.3 2.9 7.8
Nov 2010-Oct 2011
0.7 5.1 11.7 0.2 2.5 6.7
Nov 2011-Oct 2012
0.4 3.4 9.0 0.1 1.5 4.5
US method (frequency)
EU method (geometric)
(1000’s of cells/mL)750 500 400 750 500 400
Nov 2009-Oct 2010
0.2 2.0 5.8 0.1 1.0 3.1
Nov 2010-Oct 2011
0.1 1.4 4.1 <0.1 0.6 2.1
Nov 2011-Oct 2012
0.1 0.9 3.1 <0.1 0.4 1.4
•Percentage of milk supplied by US DHI herds noncompliant by SCC level
US method (frequency)
EU method (geometric)
(1000’s of cells/mL)
Herd size 750 500 400 400
Number of
herds
10-49 0.8 5.9 13.2 6.7 4,983
50-99 0.2 3.0 8.9 4.4 4,505
100-149 <0.1 1.7 6.8 3.2 1,512
150-199 0.2 1.4 5.3 2.5 718
200-299 <0.1 1.1 5.0 2.6 657
300-499 0.0 0.8 2.3 1.1 612
500-999 0.1 0.1 1.3 0.3 492
≥1000 0.0 0.1 0.8 0.3 376
All herds 0.4 3.4 9.0 4.5 13,855
<5% 5.0 to 9.9% 10.0 to 24.9% 25.0 to 50.0%
November 2009-October 2010 November 2010-October 2011 November 2011-October 2012
Percentage of herd-tests noncompliant using current EU SCC standard (400,000 cells/mL) by state
• US versus EU SCC monitoring
Program characteristic US EUSCC sample Individual farm Individual farm
Bulk tank (BT)-SCC limit
750,000 cells/mL 400,000 cells/mL
Value used Consecutive monthly BT-SCC
Geometric mean of 3-mo BT-SCC
Producer suspension
3 of 5 consecutive samples over limit
4 consecutive 3-mo means over limit
Geometric mean is mathematically lower than arithmetic mean
The EU 3-mo mean uses a single reference for the period, which allows a herd more time to reduce SCC before becoming noncompliant
•Percentage of herd-tests noncompliant by year and month using current EU SCC standard (400,000 cells/mL)
Year
•Percentage of US DHI herd-tests noncompliant November 2011 to October 2012 by herd size and SCC level
TH375 http://aipl.arsusda.gov
2013