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) 0.001a
No 114 0.65 8.2 (2.7) 0.002b
Piglet age at weaning cont. -c - - 0.116a
0.190b
Number of pens per farrowing room* >14 154 0.31 7.0 (3.3) 0.035a
≤14 160 0.52 7.6 (2.8) 0.067b
Remaining faeces after cleaning Yes 88 0.52 8.0 (3.0) 0.056a
No 226 0.37 7.1 (2.9) 0.145b
Size of farrowing pen in m2* cont. - - - 0.042a
0.113b
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.

Skampardonis et al.

Skampardonis et al. BMC Veterinary Research 2012 8:228   doi:10.1186/1746-6148-8-228

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