Epsilon Archive for Student Projects

Abstract

The objective of this work was to evaluate and compare three field methods for detection of mastitis, California Mastits Test (CMT), DeLaval cell counter DCC (DCC) and FMA2001 Farm Milk Analyzer (FMA2001). Furthermore, to investigate at what cell count level clinical symptoms of mastitis are seen, and finally to check if the clinical findings and cell counts could be related to bacteriological findings.

DCC and FMA2001 are new analytic instruments to be used on dairy farms for detection of mastitis. CMT has been a widely used cow-side-test of milk quality in mastitis control efforts, but it cannot be used for estimating cell counts in scientific studies or investigations.

Two hundred and eight quarter milk samples from 52 cows were analysed with DCC and CMT, and 168 of these samples with FMA2001. Microbiological examination was done on 38 milk samples with CMT scores of 4 and 5. Whole udder milk samples were analysed from 40 and 50 cows with FMA2001 and DCC, respectively, and compared with a fluoro-opto-electronic-cell-counting method (Fossomatic).

The results from DCC and FMA2001 had good correlation with the results from the Fossomatic. The DCC made a misdiagnosis of mastitis at the 200 000-cells/ml level in 4% of the cases compared with the Fossomatic. The lactose content of the milk, which was analysed with the FMA2001, did not work satisfactorily as indicator for mastitis compared to cell count, which were analysed with DCC.

The agreement of CMT with DCC was good enough for a field method to be used for the classification of mastitis and to give guidance in milk sampling for bacteriological examination. The results show clearly that CMT should not be used as a method for estimating cell count, because of the limited sensitivity and specificity.

There was no cut-off level in cell count between sub-clinical and clinical mastitis. The number of samples was too small to determine a lower limit of cell count in clinical mastitis, but clinical symptoms were seen at a cell count level of approximately two million cells/ml. On the other hand, the cell count level could be as high as six million cells/ml without any clinical signs.

High cell counts and clinical findings could not be related to bacteriological findings.