TABLE 2.
Cumulative percentages of eight mastitis pathogens and culture-negative samples isolated from quarter samples distributed on various cell count thresholds.
| SCC × 103 cells/mL | % CNS | % STA | % STH | % STI | % SAG | % SUB | % SDY | % SFA | % no growth |
|---|---|---|---|---|---|---|---|---|---|
| 50 | 14.8 | 7.1 | 3.0 | 22.4 | 2.7 | 5.2 | 1.4 | 4.0 | 34.6 |
| 100 | 26.2 | 11.7 | 4.8 | 34.0 | 5.8 | 10.0 | 2.8 | 7.9 | 40.3 |
| 150 | 35.0 | 12.7 | 5.5 | 42.2 | 7.1 | 14.2 | 3.6 | 11.4 | 56.9 |
| 200 | 40.0 | 14.6 | 5.9 | 46.7 | 9.0 | 16.1 | 4.2 | 14.4 | 63.1 |
| 250 | 47.3 | 21.1 | 10.4 | 53.9 | 12.5 | 21.1 | 6. 7 | 20.3 | 69.0 |
| 300 | 52.1 | 23.1 | 13.1 | 59.2 | 15.5 | 24.3 | 8.7 | 24.3 | 72.2 |
| 350 | 55.9 | 24.7 | 14.5 | 63.2 | 18.7 | 27.8 | 10.6 | 28.1 | 74.6 |
| 400 | 59.2 | 26.5 | 15. 5 | 66.4 | 21.9 | 30.9 | 12.7 | 31.6 | 76.6 |
| 450 | 62.1 | 28.5 | 17.4 | 69.2 | 25.2 | 33.2 | 14.0 | 34.5 | 78.3 |
| 500 | 64.6 | 30.1 | 18.8 | 73.2 | 26.8 | 35.8 | 16.0 | 36.6 | 79.7 |
| 750 | 73.3 | 36.2 | 25.8 | 79.3 | 37.5 | 46.4 | 24.6 | 45.3 | 84.7 |
| Sample size | 17 249 | 3657 | 2430 | 445 | 1875 | 2212 | 964 | 651 | 59236 |
Source: Milk laboratory, Faculty of Veterinary Science, University of Pretoria
n = 89 635.
SCC, somatic cell counts; CNS, coagulase-negative staphylococci; STA and STH, Staphylococcus aureus; STI, Staphylococcus pseudintermedius; SAG, Streptococcus agalactiae; SUB, Streptococcus uberis; SDY, Streptococcus dysgalactiae; SFA, Enterococcus faecalis; no growth, culture-negative samples.