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The DeLaval Direct Cell Counter (DCC) is a rapid, portable test for the quantification of SCC in milk. This study was designed to compare the DeLaval DCC to traditional in-lab methods, and to determine its usefulness in early postpartum cows. Composite samples were obtained from 120 lactating cows. Samples were analyzed using three methods for SCC determination: Fossomatic 5000, Bentley SomaCount 300 and the DeLaval DCC. A subset of these samples was tested using the DeLaval DCC both on-farm and in the laboratory. In addition, 42 cows on two farms were enrolled on the first scheduled visit to the farm after their calving (1 - 4 DIM). Three additional samplings were performed on each cow over the next two weeks. At the time of initial and subsequent sampling, a CMT test was performed, and a milk sample was aseptically collected from each quarter. The samples were transported to the University Lab for standard milk bacteriological culture, Bentley SomaCount SCC determination and the DeLaval DCC test. Results were recorded and analyzed using Microsoft Excel. Log SCC data was plotted for the DeLaval DCC instrument versus the Bentley SomaCount 300 and the Fossomatic 5000 electronic SCC instruments. There was extremely high correlation between DeLaval DCC and the standard laboratory SCC instruments, with a coefficient of correlation of 0.92 in both cases. A subset of 36 cow composite samples was evaluated with the DeLaval DCC instrument both on-farm and in the lab. There was reasonably good correlation (R2 = 0.87), indicating that on-farm use of the DeLaval DCC instrument could work well. In addition, the mean and standard deviation of the DeLaval DCC and laboratory SCC data were compared to the CMT results from postpartum cows. Both the DeLaval DCC and Bentley SCC instruments were well correlated with the CMT results. The decline of log SCC as days postpartum increased is precipitous, and equivalent using both instruments. These data suggest that the DeLaval DCC instrument could be used as a monitoring tool for udder health in the postpartum period, and for lactating cows in general. [ABSTRACT FROM AUTHOR]

There is increasing adoption of on farm culture systems for selective treatment of clinical mastitis cases. They may also be useful for the diagnosis and selective treatment of subclinical intramammary infections in fresh cows. We present preliminary validation of an on-farm culture system (Minnesota Easy Culture System II). Farm personnel collected milk samples from clinical mastitis quarters, and from fresh cow quarters that tested positive using the Californian Mastitis Test (CMT) within three days after calving. The fresh samples were then plated on farm using a sterile cotton swab onto each half of a bi-plate. Plates were incubated overnight and then interpreted as 'no growth', when bacteria did not grow, or 'Gram-positive' or 'Gramnegative' depending if growth was on the Factor or the MacConkey media half of the bi-plate respectively. After plating, milk samples were frozen and later cultured in the laboratory using standard identification procedures. On farm culture results and corresponding in laboratory results are available from 80 quarter cases of clinical mastitis, and from 87 fresh cow CMT positive quarters. Using the on-farm culture method for clinical mastitis cases, producers were able to detect 83% of the Gram-positive cases (sensitivity), and classified correctly about 90% of the Gram-negative cases or cases where bacteria was not present (specificity). Consequently, 83% of the treated cases, 'Gram-positive' quarters underwent intramammary treatment, were truly Gram-positive (predictive value of a positive test; PV+), and 90% of the not treated cases, 'Gram-negative' or 'no growth', were truly uninfected or Gram-negative (predictive value of a negative test; PV-). For fresh cow CMT positive quarters, the sensitivity of the on-farm culture to detect gram-positive quarters was 88%, and the specificity was 70%. Accordingly, 80% of the treated cases were truly gram-positive (PV+), and 81% of the not treated cases were truly uninfected or Gram-negative (PV-). [ABSTRACT FROM AUTHOR]