Dairy Herd Improvement Association (DHIA) herds had an average somatic cell count (SCC) of 228,000 in 2010, or 5,000 cells/ml less than 2009, USDA’s Animal Improvement Programs Laboratory reported this afternoon.
The data include 198,218 herd test days, and involve some 4 million cows. Note: The data reflect all cows tested, including treated cows. Milk from treated cows, however, is withheld from market. That’s why Federal Milk Market Order data on SCCs are typically lower than DHIA data.
This year’s numbers follow a constant trend of declining SCC average. The average SCC level has declined every year since 2005, and has increased only once since 2001. In 2010, 32 states and Puerto Rico had lower SCC averages than 2009. Fourteen states saw their averages increase.
Some 18% of herd test days exceed the 400,000 SCC limit at least some time during the year. And 10% exceed 500,000, and 5.7% exceed 600,000. For the full report, click here