Risk factors associated with herd-group milk somatic cell count and prevalence of coagulase-positive staphylococcal intramammary infections

摘要: Abstract Fifty nine dairy herds enrolled in the Washington State Dairy Herd Improvement Association Milk Somatic Cell Count Program were split into low and high cell-count groups. Low had lowest percentage of cows with linear-score somatic cell count (SCC) >4 highest SCC >4. An estimate prevalence intramammary infections was made from aseptically-collected milk samples. Logistic regression analysis used to construct models that would best describe combination management factors classified Similarly, stepwise linear determine management-factor combinations which herd coagulase-positive staphylococcal infection. A subset 75 variables an initial set more than 250 factors. Variables deemed have a direct effect on mastitis be under control screened using univariate tests. Those found either significantly associated SCC-group status and/or infection by staphylococci modeling procedures. Additionally, interactions tested some commonly included as forced these models. Factors most likely low-somatic-cell were: (1) milking clinical last; (2) disinfecting teat ends prior administration antibiotic therapy; (3) having drier cow bedding. model containing three 87.9% correct group. described reduction disinfection end therapy administration; applying disinfectant solution after (teat dip); cleaning milking-system regulator frequently. These decrease coagulase positive 27%, 9%, respectively, 36.6% herd-to-herd variation this pathogen.