Impact of diversity of Mycoplasma hyopneumoniae strains on lung lesions in slaughter pigs

Table 8 Results of the four final multivariable models, with severity of Mycoplasma -like lesions, prevalence of pneumonia, fissures and pleurisy as outcome variables

	β	SE	OR	CI_min	CI_max	P
Severity of Mycoplasma-like lesions
Intercept	−2.85	0.18	–	–	–
CAT						0.027
CAT 2	0.35	0.19	–	–	–	0.064
CAT 3	0.51	0.20	–	–	–	0.012
Batch						<0.001
Batch 2	0.16	0.07	–	–	–	0.027
Batch 3	0.38	0.07	–	–	–	0.0021
Distance to public road^a						0.0015
<100
>100	0.24	0.08	–	–	–	0.0015
Stand empty farrowing unit^b						<0.001
No
Yes	−0.31	0.08	–	–	–	<0.001
Not always	0.03	0.09	–	–	–	0.70
Likelihood of pneumonia
Intercept	−2.24	0.34	0.11	0.05	0.21
CAT						<0.001
CAT 2	0.26	0.27	1.30	0.77	2.19	0.33
CAT 3	0.73	0.29	2.08	1.18	3.68	0.012
Batch						<0.001
Batch 2	−0.45	0.11	0.64	0.52	0.78	<0.001
Batch 3	0.42	0.10	1.53	1.25	1.86	<0.001
Number of herds surrounding the trial herd in a perimeter <5 km	0.01	0.00	1.01	1.01	1.01	<0.001
Vaccination gilts M. hyopneumoniae ^b						<0.001
No
Yes	−0.99	0.23	0.37	0.24	0.58	<0.001
Likelihood of fissures
Intercept	−0.94	0.20	0.39	0.26	0.58
CAT						0.008
CAT 2	0.30	0.18	1.35	0.95	1.93	0.094
CAT 3	0.53	0.20	1.70	1.15	2.50	0.007
Batch						<0.001
Batch 2	0.29	0.09	1.34	1.12	1.59	0.001
Batch 3	0.74	0.09	2.09	1.75	2.48	<0.001
Distance to public road^a						0.009
<100
>100	0.26	0.10	1.30	1.07	1.58	0.009
Stand empty farrowing unit^b						<0.001
Yes	−0.40	0.10	0.67	0.55	0.82	<0.001
Not always	−0.76	0.14	0.47	0.36	0.61	< 0.001
Likelihood of pleurisy
Intercept	0.25	0.72	1.29	0.32	5.25
CAT						<0.001
CAT 2	−1.06	0.27	0.35	0.21	0.59	<0.001
CAT 3	−1.07	0.30	0.34	0.19	0.62	<0.001
Batch						0.002
Batch 2	0.35	0.10	1.41	1.16	1.72	<0.001
Batch 3	0.25	0.11	1.29	1.04	1.59	0.021
Cross fostering piglets during first week of life^b						0.002
No
<10%	−0.32	0.71	0.73	0.18	2.91	0.67
>10%	−1.96	0.77	0.14	0.03	0.64	0.040

Clinical signs M. hyopneumoniae with intensity cross fostering confounded. For severity of Mycoplasma-like lesions, a linear model was used. For the other outcome variables, a logistic model was used. For category (CAT), CAT 1 was the reference, for Batch, Batch 1 was the reference.
OR: odds ratio, CI: confidence interval, SE: standard error, P: P value, batch 1, 2, 3: referring to respectively the first, second and third sampling point in each herd, CAT (category) 1 (one M. hyopneumoniae strain per batch per herd), CAT 2: category 2 (two to six strains per batch per herd), CAT 3: category 3 (≥seven strains per batch per herd).
^a<100 m is reference category.
^bNo is reference category.

ISSN: 1297-9716