Qualifying Milk under Reduced Somatic Cell Count Limit
Dairy Pipeline: April 1999
Gerald M. (Jerry) Jones
Extension Dairy Scientist, Milk Quality and Milking Management
Will your milk qualify if the accepted somatic cell count limit is reduced from 750,000 to 400,000? The European Union (EU) has reduced their accepted level to 400,000. Any milk shipped into these countries must also be less than 400,000. The National Conference on Interstate Milk Shipments will consider this change again in May. The EU computes a geometric mean over three months rather than an arithmetic average. A geometric mean of three samples is determined by multiplying the three numbers together and calculating the cube root. The advantage to the geometric mean is that a single high somatic cell count has less impact. Not everyone agrees to the adoption of 400,000, however many feel that there is need to establish a world standard for SCC. Research results suggest that at 400,000 SCC, 13% of quarters in a herd would be infected while 24% of quarters would be infected in a herd with a bulk tank SCC of 750,000. It is unclear at this time as to how a limit of 400,000 would be regulated if accepted. The National Mastitis Council Board of Directors recommends a gradual decrease over several years. One possible implementation is that a herd would be placed on probation after two consecutive months that the geometric mean exceeds the regulatory limit and would be suspended if the third consecutive 3-month geometric mean is in violation and that tests would be conducted weekly, which is currently done by some. Successful mastitis prevention and control includes: (1) Controlling environment, housing and teat contamination between milkings, (2) Routine monitoring of milking procedures, (3) Milking sanitation and hygiene, (4) Milking system design and maintenance, (5) Dry cow management and therapy, (6) Monitoring SCC and rate and type of infection, (7) Herd segregation or backflushing, and (8) Culling chronically infected cows.