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Table 1 Odds-ratios of detecting Salmonella in broiler flock and house litter depending on parameters of grow-out lighting.

From: Lighting during grow-out and Salmonella in broiler flocks

   Parameter/its association with the outcome
Outcome sample type n Parameter Mean
(range)
OR (Wald-type 95% CI) P
Feathered carcass rinsates 1 week before the end of rearing 58 10% increase of the hours of full lights during grow-out 25.5%
(6.5%-81.2%)
1.38
(0.98, 1.95)
0.061
  58 10% increase of the hours of black-out during grow-out 12.4%
(0%-23.9%)
0.32
(0.09, 1.05)
0.060
Post-harvest drag swabs of litter from grow-out house 50 Day of grow-out when dim lights for ≥18 hours per day started 15
(3-29)
0.89
(0.78, 1.01)
0.065
Feathered carcass rinsates at arrival for processing 50 Day of grow-out when dim lights for ≥18 hours per day started 15
(3-29)
0.93
(0.85, 1.01)
0.098
Post-chilling carcass rinsates 54 10% increase of the hours of full lights during grow-out 25.5%
(6.5%-81.2%)
1.31
(0.99, 1.74)
0.062
  54 10% increase of the hours of dim lights during grow-out 62.1%
(3.2%-77.8%)
0.77
(0.56, 1.05)
0.091
  1. Association between a parameter of grow-out lighting and an outcome was tested in a multi-level mixed logistic regression model that accounted for variation in the Salmonella burden among grow-out farms within a broiler complex, complexes within a company, and between companies. The lighting parameter was tested in this model as a single fixed-effects factor, and was considered to be associated with the outcome if P ≤ 0.100; only such parameters are presented. In all these models, the variation among grow-out farms within a complex significantly (P ≤ 0.100) contributed to variability in the outcome, but not the variation among complexes within a company or between companies (all P > 0.500). n - number of flocks.