Variations in Measures of Udder Health within a Short Period of Time

Foremilk quarter samples were collected at morning and evening milkings on 6 dates during a 9 day period. At the end of the period teat puncture samples were drawn. Mastitis diagnoses based on bacteriological and cytological examinations were established for all 13 sets of samples from 45 cows (180 quarters). The effect of a fixed cell count (SCC) treshold value on mastitis diagnoses was studied as was the effect of variations in bacteriological state. The majority of shifts in diagnoses occurred only at few quarters due to the fact, that variation in the SCC–based diagnoses almost inevitably occurred in quarters with a SCC level close to the threshold. The future bacteriological state depended on both the previous and present bacteriological states in such a way, that changes in the future state seldom occurred when both the previous and present bacteriological states were the same. In conclusion, the quarter health state appeared to be fairly stable during a short period of time and the probability of changing mastitis diagnosis depended not only on the present diagnosis, but also on the actual somatic cell count and the previous bacteriological state.