1. 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) 750500400750500400 Nov 2009-Oct 20100.96.214.10.32.97.8 Nov 2010-Oct 20110.75.111.70.22.56.7 Nov 2011-Oct 20120.43.49.00.11.54.5 US method (frequency) EU method (geometric) (1000’s of cells/mL) 750500400750500400 Nov 2009-Oct 20100.22.05.80.11.03.1 Nov 2010-Oct 20110.11.44.1<0.10.62.1 Nov 2011-Oct 20120.10.93.1<0.10.41.4 Percentage of milk supplied by US DHI herds noncompliant by SCC level US method (frequency) EU method (geometric) (1000’s of cells/mL) Herd size750500400 Number of herds 10-49 0.85.913.26.7 4,983 50-99 0.23.08.94.4 4,505 100-149 <0.11.76.83.2 1,512 150-199 0.21.45.32.5 718 200-299 <0.11.15.02.6 657 300-499 0.00.82.31.1 612 500-999 0.1 1.30.3 492 ≥1000 0.00.10.80.3 376 All herds 0.43.49.04.5 13,855 <5% 5.0 to 9.9% 10.0 to 24.9% 25.0 to 50.0% November 2009-October 2010November 2010-October 2011November 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 characteristicUSEU SCC sampleIndividual farm Bulk tank (BT)- SCC limit 750,000 cells/mL400,000 cells/mL Value usedConsecutive 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 ) SCC (1000s) Year Percentage of US DHI herd-tests noncompliant November 2011 to October 2012 by herd size and SCC level TH37 5 http://aipl.arsusda.gov 2013