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Table 4 Multivariable linear regression analysis of the effect of seroconversions to C. burnetii on goat weights.

From: A longitudinal study of serological responses to Coxiella burnetii and shedding at kidding among intensively-managed goats supports early use of vaccines

Model Variable Levels n Coef. SE (coef.) p value 95% CI of Coef.
Effect of seroconversion on weight at weaninga Cohort Cohort 2 49 −4.84 0.88 < 0.001 −6.61, −3.08
Cohort 1 13 0.00 (ref)    
Sex Male 4 3.64 1.46 0.016 0.71, 6.56
Female 58 0.00 (ref)    
Time of first seroconversion After 28 weeks 10 −0.33 1.00 0.740 −1.03, 2.35
10–28 weeks 17 0.66 0.84 0.435 −2.36, 1.66
0–10 weeks 35 0.00 (ref)    
Intercept 17.71 0.89 < 0.001 15.93, 19.48
Effect of seroconversion on weaning to breeding weight changeb Cohort Cohort 2 38 5.27 1.41 0.001 2.43, 8.11
Cohort 1 12 0.00 (ref)    
Time of first seroconversion After 28 weeks 3 0.98 2.52 0.700 −4.09, 6.04
10–28 weeks 16 −0.60 1.31 0.652 −3.23, 2.04
0–10 weeks 31 0.00 (ref)    
Intercept 7.67 1.40 < 0.001 4.86, 10.49
  1. Interpretation: a No statistically significant difference in weaning weight was observed between goats that seroconverted before breeding and those that seroconverted post-breeding after adjusting for cohort and sex. However, goats in cohort 2 had weighed 4.84 kg lower at weaning than goats in cohort 1
  2. bSimilarly, no statistically significant difference in weaning-breeding weight change was observed between goats that seroconverted before breeding and those that seroconverted post-breeding after adjusting for cohort. Surprisingly, goats in cohort 2 weighed 5.27 kg more than goats that had not seroconverted by breeding. Sex was not included in modelb because all male animals were lost from the study by breeding time