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Table 2 Final logistic regression model with random herd effect for logit-transformed seroprevalence of BLV in Japan

From: Risk factors associated with within-herd transmission of bovine leukemia virus on dairy farms in Japan

Variable
Level
β1 SE2 z-value P of z-value
Intercept -0.36 0.59 -0.62 0.54
Housing conditions     
   Tied system Ref.3    
   Loose system 0.71 0.316 2.23 0.03
Animal dehorning     
   No Ref.    
   Yes 1.11 0.302 3.66 0.0002
Presence of horseflies in summer     
   Never or seldom Ref.    
   Sometimes or often -0.24 0.341 -0.70 0.49
   Very high 0.82 0.321 2.56 0.01
Colostrum feeding     
   No Ref.    
   From dam to calves -1.11 0.52 -2.13 0.03
   Pooled -0.90 0.55 -1.65 0.10
  1. 1estimated coefficients, 2standard error for the coefficient, 3reference category
  2. Standard deviation in mixing distribution = 1.054, Standard error = 0.099
  3. Starting from the full model with seven variables selected by univariate analyses, the best model was constructed on the basis of AIC. The best model with the smallest AIC included housing system, dehorning, observable presence of horseflies, and direct colostrum feeding. The coefficients (β values) indicate that loose housing, dehorning, and observation of a large number of horseflies in summer were positively associated with seroprevalence on infected farms (β values > 0, p values < 0.05). In contrast, feeding of colostrum was negatively associated with seroprevalence in the infected farms (β = -1.11, p = 0.03)