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Staph Aureus

Mastitis caused by Staph aureus bacteria is extremely difficult to control by treatment alone. Successful control is gained only through prevention of new infections and cow culling.S. aureus organisms colonize abnormal teat ends or teat lesions. Infected cows must either be culled, segregated from the milking herd and milked last or milked with separate milking units, or teat cup liners must be rinsed and sanitized after milking infected cows. Cows infected withS.aureus do not necessarily have high SCC. In several research trials, 3-8% of first lactation cows were found infected with S. aureus at calving. Many remain infected throughout the first lactation and are reservoirs for infecting other cows in the herd. Although as many as half of the cows with high SCC may be infected withS. aureus, somatic cell counts alone are not sensitive enough to positively diagnose S. aureus infections. Culture of bulk tank milk is easy, economical, and important aid in determining the Staph aureus status in the herd. A culture of only one bulk tank sample is not a complete guarantee that contagious mastitis will be detected asS. aureus infected cows may shed the organism intermittently. Sample three consecutive full bulk tanks and freeze the samples. Sterile plastic sample vials should be used and frozen samples sent to the lab on ice packs.  Turnaround time: 48 hours