[Udder infections with coagulase-negative staphylococci in freshly calved heifers]

To determine the prevalence of udder infections in fresh calved heifers all quarters of 98 heifers on eleven commercial farms were sampled weekly during the first eight weeks of lactation. The samples during the first four weeks of this period were used for bacteriological examination and in all samples a somatic cell count was made. The prevalence of S. aureus after calving in these heifers was 12.5%. Coagulase-negative staphylococci (CNS) were isolated from half of the heifers. The predominant coagulase-negative staphylococcus species were S. xylosis and S. hyicus. The CNS, with exception of S. hyicus, had a very small effect on the cell count.