Factors associated with the occurrence and level of Isospora suis oocyst excretion in nursing piglets of Greek farrow-to-finish herds

Table 1 Proportion of positive litters and mean (SD) of the natural logarithm for the OPG of the positive litters by the factors selected for multivariable analysis, in a two-part model, under tri-variable screening (with factor TOLTRAZURIL forced in the model), for the association with the odds (logistic part - Part I) and the level (linear part - Part II) of Isospora suis oocyst excretion

Definition of factor	Level	Number of litters	Proportion of positive litters	Mean (SD) ln(OPG)	P
Part I + Part II
Use of toltrazuril	Yes	200	0.30	6.6 (3.1)	0.001^a
	No	114	0.65	8.2 (2.7)	0.002^b
Piglet age at weaning	cont.	-c	-	-	0.116^a
					0.190^b
Number of pens per farrowing room^*	>14	154	0.31	7.0 (3.3)	0.035^a
	≤14	160	0.52	7.6 (2.8)	0.067^b
Remaining faeces after cleaning	Yes	88	0.52	8.0 (3.0)	0.056^a
	No	226	0.37	7.1 (2.9)	0.145^b
Size of farrowing pen in m^2*	cont.	-	-	-	0.042^a
					0.113^b
Part I
Cross-fostering of piglets	Within the 1st day p.f.^** no fostering	60	0.26	6.8 (2.5)	0.061
	After 1st day p.f.	254	0.44	7.4 (3.1)
Cleaning entire farrowing room	Yes	193	0.34	7.4 (2.7)	0.077
	No	121	0.63	7.3 (3.5)
Disinfection of farrowing unit on a regular basis	Yes	290	0.40	7.4 (3.0)	0.050
	No	24	0.56	7.6 (3.3)
Flooring of farrowing pen in creep area^*	Perforated	91	0.27	6.3 (3.1)	0.070
	Solid	223	0.51	7.8 (2.9)
Number of caretakers in farrowing unit	>2	55	0.24	6.3 (2.7)	0.186
	≤2	259	0.48	7.6 (3.0)
Farrowing pen flooring^*	Plastic	89	0.38	7.1 (3.3)	0.160
	Metal	225	0.41	7.5 (2.9)
Slatted portion of farrowing pen’s flooring^*	30%	55	0.27	8.5 (2.3)	0.171
	60%	111	0.48	7.7 (2.6)
	100%	148	0.40	6.7 (3.3)
Part II
Use of drying substances	Yes	115	0.31	7.3 (2.9)	0.170
	No	199	0.48	7.4 (3.1)
Caretakers entering pens	Yes	294	0.41	7.5 (3.0)	0.110
	No	20	0.34	5.7 (2.4)
Mechanical ventilation in farrowing unit	Yes	207	0.39	7.5 (2.6)	0.169
	No	107	0.45	7.0 (3.8)
Washing water	Cold	255	0.40	7.4 (3.2)	0.002
	Hot	59	0.38	7.1 (2.5)

Dual P-values correspond to factors that were offered to both parts of the model. Data are from 314 litters in 55 farrow-to-finish Greek pig herds.
^aP-values for Part I. ^bP-values for Part II. * Litter-level variables. ** Post farrowing.

ISSN: 1746-6148