Do You Beat Your State Average for Somatic Cells?

March 10, 2020

Jim Dickrell

The most recent analysis of somatic cells counts (SCCs) shows continued improvement, with U.S. herds averaging less than 200,000 cells/mL for the third consecutive year in a row.

The 2019 average of 187,00 cells/mL is the lowest level the United States Department of Agriculture and the Council on Dairy Cattle Breeding (CDCB) have reported since they began calculating state and national SCCs in 1995, when it was 304,000.

“Variation among states remains large,” says Duane Norman, CDCB technical consultant and industry liaison. “State average SCC generally was lower than the national average for the northeastern, mountain, and western states and often higher for the southeastern states.”

Vermont reports the lowest SCC average in the nation, with its herds averaging 154,000 cells/mL. Michigan is second best, with an average SCC of 159,000 cells/mL.

Some southern states remain problematic, with Alabama reporting an average SCC of 454,000 and Arkansas reporting an average of 414,000 cells/ml. Alabama also had 12.3 percent of its herd test days exceeding 750,000.

“Although climatic conditions (temperature and humidity) surely contributed to regional SCC levels, differences between adjacent states were substantial, suggesting herd size and mastitis-control practices are impacting state differences as well,” Norman says.

Small herds typically have higher SCC levels. In these herds, one subclinical cow can contribute large numbers to the bulk tank SCC. In the 2019 CDCB data set, herds with less than 50 cows had an average SCC of 230,000 cells/ml. Herds with 4,000 or more cows averaged 174,000 SCC.