A cross-sectional survey of 523 dairy farms in the south of Chile was carried out to quantify risk factors associated with bulk-milk somatic-cell count (BMSCC) >200 × 103 cells/ml. Questionnaires followed by one reminder were sent to 3710 dairy farms via the 11 milk-processing plants that they supplied in October 1998. The response proportion was 14.1%. The median BMSCC was 289 × 103 cells/ml (range: 74 × 103 to 1800 × 103 cells/ml). The median herd size was 70 cows (range: 7-616); herd size was not associated with BMSCC. The annual milk yield of 33.2% of the herds was <40001 and 53.4% had an annual milk yield of 4 × 103 to 6 × 103 1. Clinical-mastitis records were kept by 55.3% of the farmers. Seventy-six percent of the farmers (377/499) reported <10 clinical cases of mastitis in the year prior to the questionnaire. Logistic multiple regression indicated that BMSCC >200 × 103 cells/ml was more likely when foremilking was practised, and when cows were collected in a yard before milking. BMSCC was less likely to be >200 × 103 cells/ml when teats were washed with water containing disinfectant compared with plain water; when the udder and teats were always checked before milking compared with, sometimes or never; when cows with mastitis were milked first compared with any other ordering, and when farmers recorded individual-cow somatic-cell count (ICSCC) compared with when ICSCC was not recorded.
Bibliographical noteFunding Information:
We thank the milk-processing plants for their help in this study, and all the farmers who returned the questionnaire. We also thank Edmund Peeler for permission to use his questionnaire as a basis for the one used in this study and Martin Green for his helpful comments on the manuscript. This study was funded by the British Council (SAN/984) and Pharmacia Upjohn.
- Bulk-milk somatic-cell count
- Dairy cows
- Risk factors
ASJC Scopus subject areas
- Food Animals
- Animal Science and Zoology