Somatic cell count (SCC) in Dairy Herd Improvement (DHI) herds enrolled in SCC testing in the US averaged 217,000 cells/ml in 2011, which was less than the 2010 average of 228,000. This compares to 233,000 in 2009; 262,000 in 2008; 276,000 in 2007; and 288,000 in 2006.
Variation among states remains large, ranging from less than 160,000 to more than 400,000. State average SCC was lower than the national average for mountain and western states, and often higher for southeastern states.
Average test-day somatic cell count from US Dairy Herd Improvement herds during 2011 by state
The current federal SCC regulatory limit in the U.S. is 750,000 cells/ml. In many other major dairy countries, the SCC limit is 400,000 cells/ml.
The overall percentage of herd test days that exceeded 400,000, 500,000, 600,000, and 750,000 cells/ml during 2010 were 15.7%, 8.5%, 4.8% and 2.3%, respectively, which was lower for all levels than during 2010. The 2.3% of 2011 DHI herd test days that were higher than the present legal limit for bulk tank SCC in the US may overestimate the percentage of herds that shipped milk exceeding the legal limit because milk of cows treated for mastitis is excluded from the bulk tank even though included in DHI test data. The percentage of herd test-days that exceeded the legal limit also would have been higher than the percentage of herds that were rejected from the market because market exclusion only occurs after repeated violations.
[Read more]
