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Title: Consequence for dairy herds in the United States of imposing different standards for somatic cell count

Author
item Norman, H
item Wright, Janice
item MILLER, ROBERT - Retired ARS Employee

Submitted to: Mastitis Council Meeting Proceedings
Publication Type: Proceedings
Publication Acceptance Date: 12/30/2010
Publication Date: 1/23/2011
Citation: Norman, H.D., Wright, J.R., Miller, R.H. 2011. Consequence for dairy herds in the United States of imposing different standards for somatic cell count. Mastitis Council Meeting Proceedings, Arlington, VA, Jan. 23-26, pp. 119-120.

Interpretive Summary: New European Union (E.U.) regulations may require that a somatic cell count (SCC) limit of 400,000 cells/mL for milk be met by every farm that contributes to pooled milk exported to Europe. In the United States, the standard is 750,000 cells/mL. Because bulk tank SCC is not readily available throughout the United States, somatic cell score (SCS), a logarithmic transformation of SCC, often is used as a reflection of milk quality. Monthly SCS recordings were available for 97% of Dairy Herd Improvement herds. Percentages of U.S. herds that were noncompliant for E.U. or U.S. SCC standards as well as the amount of milk that was associated with those herds were examined by month, herd size, and State. The average percentage of herds that were SCC-noncompliant from October 2009 through September 2010 was 0.8% for U.S. and 7.4% for E.U. standards. The percentage of U.S. herds impacted was far greater than the impact on the U.S. milk supply; only 0.2% (U.S.) and 3.0% (E.U.) of U.S. milk produced did not meet SCC standards. Percentages of SCC-noncompliant U.S. herds and U.S. milk decreased as herd size increased for both U.S. and E.U. standards. The southeastern United States generally had the highest percentages of SCC-noncompliant herds and milk produced for both standards. However, the greatest numbers of noncompliant herds were in Pennsylvania, Minnesota, and Wisconsin. Those U.S. dairy producers who are required to meet the more stringent E.U. SCC standards will need to place more attention on milking management and culling practices.

Technical Abstract: New European Union (E.U.) regulations may require that a somatic cell count (SCC) limit of 400,000 cells/mL for milk be met by every farm that contributes to pooled milk exported to Europe. In the United States, the standard is 750,000 cells/mL. Because bulk tank SCC is not readily available throughout the United States, somatic cell score (SCS), a logarithmic transformation of SCC, often is used as a reflection of milk quality. Monthly SCS recordings were available for 97% of Dairy Herd Improvement herds. Percentages of U.S. herds that were noncompliant for E.U. or U.S. SCC standards as well as the amount of milk that was associated with those herds were examined by month, herd size, and state. Monthly percentage of U.S. herds that were SCC noncompliant from June 2009 through September 2010 ranged from 0.5 to 1.1% for U.S. standards and 6.3 to 8.4% for E.U. standards. Noncompliance was greatest following summer production. Weighted means for U.S. herd noncompliance for the last available 12 months (October 2009 through September 2010) were 0.8% for U.S. and 7.4% for E.U. standards. The percentage of U.S. herds impacted was far greater than the impact on the U.S. milk supply; only 0.2% (U.S.) and 3.0% (E.U.) of U.S. milk produced did not meet SCC standards. Monthly percentage of U.S. milk that was SCC noncompliant from June 2009 through September 2010 ranged from 0.1 to 0.2% for U.S. standards and 2.6 to 3.4% for E.U. standards. Percentages of SCC-noncompliant U.S. herds and U.S. milk decreased as herd size increased for both U.S. and E.U. standards. Percentage of herds that were noncompliant based on the U.S. standard was 4% or more for Arkansas, Florida, Kentucky, and Tennessee; 3% for Louisiana and Missouri; and 2% or less for all other states; E.U. noncompliance ranged from 21 to 39% for herds in Arkansas, Kentucky, Oklahoma, Tennessee, and coastal states from Louisiana eastward to Georgia. The greatest numbers of noncompliant herds were in Pennsylvania, Minnesota, and Wisconsin for both U.S. and E.U. standards. Percentages of U.S.-noncompliant milk were highest for Arkansas, Kentucky, Louisiana, Missouri, and Tennessee (2% or more); percentages of E.U.-noncompliant milk were highest for Alabama, Arkansas, Georgia, Louisiana, Oklahoma, and Tennessee (21 to 42%). Those U.S. dairy producers who are required to meet the more stringent E.U. SCC standards will need to place more attention on milking management and culling practices.