Table 3.

Mixed-effects multi-level logistic regression analysis for influenza A virus (IAV) seropositivity

Parameter	Odds ratio	Standard error	95% confidence interval	p-value
M. hyo seropositivity
No	Referent
Yes	1.66	0.31	1.15–2.41	0.007
Production stage
At weaning	3.10	0.54	2.20–4.35	<  0.001
End of nursery	Referent
End of grower	2.30	0.40	1.63–3.22	< 0.001
End of finisher	2.89	0.52	2.03–4.10	< 0.001
Cohorta
One	Referent
Two	3.64	0.98	2.15–6.16	< 0.001

This table displays the mixed-effects multi-level logistic regression analysis for influenza A virus (IAV) seropositivity with farrowing source and sow as random effects in 9 seropositive groups that had more than 20% of pigs test seropositive to IAV by ELISA

M. hyo = Mycoplasma hyopneumoniae

^aCohort One: Pigs were born between May and August; Cohort Two: Pigs were born between October and January