title: Risk factors for clinical mastitis in herds with a low bulk milk somatic cell count. 1. Data and risk factors for all cases.
abstract: The incidence rate of clinical mastitis in 125 herds with a low annual bulk milk SCC (less than 150,000 cells/ml) was modeled using a Poisson regression model. The rate of clinical mastitis was significantly associated with some variables that increased the exposure to environmental microorganisms: poor cubicle cleanliness increased the mastitis rate; rubber mats in cubicles were associated with a higher incidence; and drinking water from sources other than public water also increased the rate of mastitis. Other variables may be associated with host resistance: an increasing percentage of cows leaking milk increased the rate of mastitis; postmilking teat disinfection was associated with a higher incidence of clinical mastitis; and a high frequency of cubicle disinfection was also associated with more mastitis. Three other variables were associated with the rate of mastitis: breed (Holstein-Friesian had a lower incidence than the Meuse-Rhine-Yssel breed); use of sugar beet pulp in the ration increased the mastitis rate; and in herds with high milk production a higher incidence of mastitis was observed. These items are discussed in respect to their causal relation to clinical mastitis.
authors.affiliation: Department of Herd Health and Reproduction, Utrecht, The Netherlands.
authors.forename: Y H
authors.initials: YH
authors.lastname: Schukken
authors.forename: F J
authors.initials: FJ
authors.lastname: Grommers
authors.forename: D
authors.initials: D
authors.lastname: Van de Geer
authors.forename: H N
authors.initials: HN
authors.lastname: Erb
authors.forename: A
authors.initials: A
authors.lastname: Brand
mesh_terms: D000818:Animals; D001947:Breeding; D002417:Cattle; D002452:Cell Count / Q000662:veterinary; D004203:Disinfection; D005260:Female; D006799:Housing, Animal; D015994:Incidence; D008414:Mastitis, Bovine / Q000453:epidemiology* / Q000209:etiology; D008892:Milk / Q000166:cytology*; D016012:Poisson Distribution; D012307:Risk Factors; D014881:Water Supply