COMPARISON OF SOMATIC CELL COUNTING DEVICES IN COWS' MILK: EVALUATING ACCURACY AND RELIABILITY OF DELAVAL CELL COUNTER, AND LACTOSCAN SCC WITH FOSSOMATIC METHODS

Abstract

This study aimed to compare three devices (Delaval cell counter / DCC, Lactoscan SCC / LSc SCC (somatic cell count), and Fossomatic FC / FSCC) used to determine the number of somatic cells in cow's milk. The agreement, sensitivity, and specificity of DCC and LSc SCC were evaluated against Fossomatic FC from the accredited laboratory of the Breeding Services of the Slovak Republic. The SCC results obtained from the Fossomatic FC are widely regarded as the benchmark or reference standard. The threshold of somatic cells for subclinical mastitis was 200,000 SC/mL. Mixed milk samples (a sample from all quarters) form of 144 Holstein-Friesian dairy cows were used in the study. Results were analyzed statistically using the Pearson correlation test. Subclinical mastitis was detected in 62 cows (43.1%) by FSCC, in 63 cows (43.8%) by DCC, and in 50 cows (34.7%) by LSc SCC. DCC matched with FSCC in 91.0% of samples, and LSc SCC matched in 86.8%. The sensitivity and specificity for DCC were 91.1% and 92.1%, respectively, and for LSc SCC, they were 79.5% and 94.3%. The correlation coefficient between FSCC and DCC reached 0.91 (P < 0.001), and between FSCC and LSc SCC, it was 0.73 (P < 0.001). The results obtained in the present study point to a conclusion that tested methods prove their different quality to somatic cell counting. Compared to Delaval Cell counter, Lactoscan SCC has a lower agreement with Fossomatic SCC, but also a lower detection of subclinical mastitis than other methods. In addition to these results, each of the two analyzers also has certain benefits. DCC provides easy and quick measurements of SCC on the farm. LSc SCC is cheaper, but it is less accurate.