Portable Conductivity Meter for Detecting Abnormal Milk

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Abstract
A hand-held conductivity meter was designed for cow-side detection of abnormal milk. Each instrument contains a single flow cell and 4 sealed push-button switches to select individual quarters. The instrument can be configured for examining Holstein or Jersey type milk by adjusting tube length. Each quarter reading is displayed immediately on a liquid crystal digital display and is comparable with other quarter readings. Milk samples from 626 individual quarters (162 cows) were collected from 2 Holstein and 2 Jersey herds and tested with the hand-held conductivity meter. Samples also were analyzed for somatic cells, fat, protein, lactose, pH, total bacterial count, and predominant bacterial groups. The correlation between conductivity and lactose was largest and negative. Somatic cell count, protein, and pH were positively correlated with conductivity. Correlations of conductivity were the highest in the herd with largest incidence of abnormal milk. The meter classified correctly more quarters with abnormal milk than any measure in discriminant anlaysis when quarters were classified into presence or absence of abnormal milk.