Treatment of shoulder ulcers in sows – rubber mats and zinc ointment compared to chlortetracycline spray

Table 3 Explanatory variables in three different models studying treatment of shoulder ulcer in sows ^a

Day of observation	Number of observations included	Model	P-value for statistical association between explanatory variable and response
			Treatment	Body condition	Treatment * Body condition	Parity	Size of ulcer on Day 1	Herd	Herd * treatment * Body condition
1	299	Full model	0.72	0.65	0.67	0.86	Not relevant	0.0060	Not relevant
		Final model with significant variables only	NS	NS	NS	NS	Not relevant	0.0047	Not relevant
14	299	Full model	<0.0001	0.30	0.0004	0.09	<0.0001	0.0014	0.14
14		Final model with significant variables only	<0.0001	0.10	0.0005	NS	<0.0001	0.0038	NS
14^b	299	Final model with significant variables only^c	<0.0001			NS	<0.0001	0.0038	NS
21	220	Full model	<0.0001	0.29	0.45	0.05	<0.0001	0.23	0.10
		Final model with significant variables only	<0.0001	NS	NS	0.03	<0.0001	NS	NS
21^b	220	Final model with significant variables only^c	<0.0001			NS	<0.0001	NS	NS

^a: For each sow at each time of observation the size of the largest ulcer was chosen. NS: Non-significant implies that the P-value was >0.05.
^b: The side of lesion on day 1 was identified separately for the model describing lesion sizes at day 14 and day 21, separately.
^c: In this model a new variable was created based on a combination of the two variables Body condition (lean/fat) and Treatment (rubber mats and zinc ointment versus cutaneous antibiotics). This new variable had four levels.

ISSN: 1751-0147