Can DHI samples be used for bacterial culture?
No. DHI samples cannot be used for mastitis culture because they have a preservative added. This prevents bacterial growth which is needed for mastitis bacteria identification in the lab. Also, samples for culture must be kept refrigerated or frozen between collection and arrival at the lab. Can samples for bacterial culture be collected from the meters like DHI SCC and composition samples? No. Although the meters and milking equipment are routinely cleaned and sanitized some bacteria may be added to the milk in passage. This is not enough to cause milk quality problems such as elevated plate loop counts (PLCs). However, if these bacteria are in the samples collected from the meters and grow on the cultures at the mastitis diagnostic lab it is impossible to determine whether the bacteria came from a mastitis infection in the cow or from the milking equipment. Additionally, these equipment bacteria multiply rapidly and can “overgrow” or hide mastitis bacteria so that they cannot be iden
