Table 3.

Results of univariate analysis of risk factors for stillbirth (995 piglets).

Covariates	Stillbirth rate	OR; 95 CI	Nagelkerke R2	p-value
Born before the use of O	3.9 (20/511)	1	0.0791
Born after 1 dose of O	10.5 (45/433)	2.85; 1.65-4.90	<0.001
Born after 2 doses of O	31.4 (16/51)	11.22; 5.35-23.56	<0.001
Parity 6-10	11.7 (42/360)	1	0.0285
Parity 2	1.2 (1/86)	0.09; 0.01-0.66	0.018
Parity 1	5.0 (6/121)	0.40; 0.16-0.95	0.039
Parity 3-5	7.5 (32/428)	0.61; 0.10-0.18		0.046
GL=114-116 days	6.9 (52/751)	1	0.0155
GL=117-119 days	9.4(16/170)	1.40; 0.78-2.51		0.265
GL=112-113 days	17.6 (13/74)	2.86; 1.48-5.55		0.002
Female	8.0 (36/450)	1	<0.001
Male	8.3 (45/545)		1.035; 0.66-1.63	0.883
LS		1.08; 1.007-1.16	0.082	0.032
BO		1.19; 1.13-1.25	0.0834	<0.001
BI		1.007; 1.003-1.01	0.0239	<0.001
CFD		1.004; 1.003-1.006	0.0594	<0.001
BW		0.92; 0.88-0.97	0.0167	0.002
CRL		1.02; 0.93-1.11	0.0003	0.681
BWD		0.39; 0.21-0.70	0.0174	0.002
BMI		0.90; 0.85-0.94	0.0352	<0.001
PI		0.97; 0.95-0.98	0.042	<0.001

OR=Odds ratio, CI=Confident interval, p=Probability level, O=Oxytocin, GL=Gestation length, LS=Litter size, BO=Birth order, BI=Birth interval, CFD=Cumulative farrowing duration, BW=Birth weight, CRL=Crown rump length, BWD=Birth weight deviation, BMI=Body mass index, PI=Ponderal index