Volume 15, Number 5—May 2009
A Case–Control Study on the Origin of Atypical Scrapie in Sheep, France
|Variable||Coefficient (β)||Standard error (β)||p value†|
|Random coefficient||0||2.00 × 10–5|
|Intercept||−1.51||0.24||2 × 10–10|
|No. animals tested during 2002–2006||0.04||0.01||6 × 10–10|
|Sheep dairy farm||2.71||0.78||2 × 10–5|
|Corn silage in C0||−1.81||0.59||5 × 10–4|
|Vitamin and mineral supplements in C0||−0.51||0.33||0.02|
|Interaction term between sheep dairy farm and vitamin and mineral supplements in C0||−1.69||0.88||0.04|
*For categorical variables, the reference value was no. C0, birth cohort assuming that in each flock all animals born during the same birth campaign (defined from July 1 of year n – 1 to June 30 of year n) shared the same exposure.
†By log likelihood ratio test.