The elusive sub-clinical mastitis

A cow’s immune system is vulnerable after calving, which creates the perfect opportunity for bacteria to pounce. While clinical mastitis can be easily detected, the elusive sub-clinical mastitis is more of a challenge. Mark Kirkpatric from Zoetis discussed this topic at length during a National Mastitis Council annual meeting in the US. “Somatic cell counts greater than 200 000 cells/ml are indicative of a subclinical mastitis infection,” he says. Dairies that conduct monthly individual cow SCC testing through DHI can monitor early lactation udder health through first test-day somatic cell counts.

He says lactation records for the presence of a high first-test somatic cell count, or a recorded clinical mastitis case in the first 60 days in lactation. Records, representing 164,423 Holstein cows, were obtained from 22 Western herds.

A cow was declared sub-clinically infected if somatic cells were above 200 000 cells/ml at the first DHI test. Lactation curves were created for cows with or without a high first-test SCC and for cows with or without a mastitis infection in the first 60 days in milk. To see the charts and read further, click HERE.