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Table 6 Results from the multivariable logistic regression analysis of factors associated with being a cow newly or chronically infected with subclinical mastitis in 578 dairy cows from 262 Swedish dairy herds (r2 = 00.6)

From: Etiology and antimicrobial susceptibility of udder pathogens from cases of subclinical mastitis in dairy cows in Sweden

Variable β SE(β) ORa 95% CIb
(ORa)
P-value
Intercept -0.17 0.17 - - -
Bacteriological finding      
1: No bacterial finding Ref.c - - - -
2: Staphylococcus aureus 0.71 0.27 2.03 (1.17; 3.52) 0.01
3: Coagulase-negative 0.17 0.27 1.18 (0.68; 2.06) 0.55
staphylococci      
4: Streptococcus 0.82 0.33 2.27 (1.12; 4.60) 0.02
dysgalactiae      
5: Streptococcus uberis 1.02 0.35 2.78 (1.38; 5.62) 0.004
6: Escherichia coli 0.67 0.58 1.95 (0.68, 5.62) 0.21
7: Other bacteria 0.63 0.38 1.87 (0.88; 4.00) 0.11
8: Contaminated 0.002 0.27 1.00 (0.58; 1.72) 0.99
Days in milk (centered) 0.005 0.0009 n.a.d n.a.d n.a.d
Days in milk (squared) -0.00001 0.000004 1.56e 1.33; 1.83 0.006
  1. aOR = odds ratio
  2. bCI = confidence interval
  3. cRef. = reference category
  4. dn.a. = not applicable
  5. eOdds ratio is calculated for an interquartile increase from the mean in days in milk (85.5 DIM) in both DIM (centered) and DIM (squared)