Milk quality in the U.S. is monitored by USDA in conjunction with NMC. The U.S. Department of Agriculture (USDA) Animal and Plant Health Inspection Service’s Centers for Epidemiology and Animal Health (CEAH), in conjunction with the USDA Agricultural Marketing Service (AMS) and the National Mastitis Council (NMC) Milk Quality Monitoring Committee, monitor milk quality in the U.S. using bulk tank somatic cell count (BTSCC) data provided by four of the nation’s 10 Federal Milk Marketing Orders (FMOs).

In 2010, four FMOs were monitored: Central, Mideast, Southwest and Upper Midwest. These FMOs monitored milk from 33,912 producers located in 34 states and accounted for nearly half of the nation’s milk supply.

2010 bulk tank SCC data
The milk-weighted geometric BTSCC mean was 224,000 cells/ml in 2010. The milk-weighted BTSCC takes into account the amount of milk shipped by a producer, resulting in an overall BTSCC mean of monitored milk.

In comparison, the milk-weighted geometric BTSCC was 227,000 in 2009; 247,000 in 2008; 260,000 in 2007; 249,000 in 2006; and 258,000 in 2005.

The producer shipment BTSCC was 272,000 in 2010. The producer shipment BTSCC is a geometric, nonmilk-weighted mean of all shipments (i.e. all shipments have equal weight).

Bulk tank SCC report

Evaluating BTSCC levels
More than 99 percent of the milk and 98 percent of the shipments monitored in these FMOs during 2010 met the current Pasteurized Milk Ordinance SCC federal regulatory limit of 750,000. Of the 31,912 producers, 91.2 percent shipped milk with BTSCC below 750,000 during all months monitored.

In 2010, during all monitored months, 89.5 percent of the milk would have met a goal of 400,000 SCC (which is the current European Union SCC limit); but only 50.7 percent of the producers would have done so.

Seasonal trends
Monthly monitoring continues to show that BTSCC peak during the summer months (July–September). In 2010, monthly milk-weighted BTSCCs were highest in August (262,000) and lowest in December (197,000).

For more information on the study, including state comparisons, visit