Exploring relationships between whole carcass condemnation abattoir data, non-disease factors and disease outbreaks in swine herds in Ontario (2001–2007)

Table 4 Univariable random effects negative binomial model

Variable	IRR	Standard error	P-value	95% confidence interval
Year
2001	(Referent)
2002	1.02	0.05	0.71	0.92 – 1.13
2003	1.10	0.06	0.07	0.99 – 1.22
2004	1.23	0.07	<0.001	1.11 – 1.36
2005	1.30	0.07	<0.001	1.17 – 1.45
2006	0.96	0.06	0.49	0.86 – 1.08
2007	0.91	0.05	0.11	0.81 – 1.02
Season	(Referent)
Winter	1.07	0.04	0.08	0.99 – 1.16
Spring	1.04	0.04	0.33	0.96 – 1.12
Summer	0.90	0.04	0.01	0.83 – 0.98
Fall
Census agriculture region
Central Ont.	(Referent)
Eastern Ont.	1.25	0.28	0.33	0.80 – 1.94
Northern Ont.	0.92	0.29	0.78	0.49 – 1.69
Southern Ont.	2.37	0.41	<0.001	1.69 – 3.33
Western Ont.	0.96	0.18	0.81	0.67 – 1.37
Log ₁₀ total processed per year	0.67	0.02	<0.001	0.63 – 0.70
Median quarterly stock price	1.003	0.0006	<0.001	1.002 – 1.004

Univariable random intercept negative binomial model with abattoir as a random effect, modeling the association between condemnation rates in provincial abattoirs in Ontario and year, season, census agricultural region, log₁₀ total hogs processed per year, and median quarterly hog stock price.

ISSN: 1756-0500