title: Risk factors associated with BMSCC greater than 200 000 cells/ml in dairy herds in southern Chile.
abstract: 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 x 10(3)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 x 10(3) cells/ml (range: 74 x 10(3) to 1800 x 10(3)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 <4000 l and 53.4% had an annual milk yield of 4 x 10(3) to 6 x 10(3) l. 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 x 10(3)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 x 10(3)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.
authors.affiliation: Instituto de Ciencias Cli;nicas, Fac. de Ciencias Veterinarias, Universidad Austral de Chile, Casilla 567, Valdivia, Chile. ntadich@uach.cl
authors.forename: N
authors.initials: N
authors.lastname: Tadich
authors.forename: J
authors.initials: J
authors.lastname: Kruze
authors.forename: G
authors.initials: G
authors.lastname: Locher
authors.forename: L E
authors.initials: LE
authors.lastname: Green
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000209:etiology / Q000517:prevention & control*; D002677:Chile; D003430:Cross-Sectional Studies; D003612:Dairying; D003625:Data Collection; D004202:Disinfectants; D005260:Female; D008321:Mammary Glands, Animal / Q000473:pathology; D008414:Mastitis, Bovine / Q000209:etiology / Q000517:prevention & control*; D008892:Milk / Q000166:cytology*; D011247:Pregnancy; D012044:Regression Analysis; D012307:Risk Factors
chemical_list: D004202:Disinfectants