Table 5.

Behavior of the training pigs during positive and negative treatments in two situations: without the presence of two naive pen mates and in the presence of two naive pen mates in the test room

	Without naive pigs present			With naive pigs present		Effects1
	Positive	Negative	T2	Positive	Negative	T2	S	TS
Behavior
Standing alert (% of time)	0.3 ± 0.1	32.9 ± 3.1	***	2.8 ± 1.2a	49.0 ± 4.6c	***	**	*
Escape attempts (% of pens)3	0	62.5	***	0	31.3	*	NS	–
Play (% of pens)3	100	0	***	93.8	0	***	NS	–
Urinating (% of pens)3	6.3	93.8g	***	0	62.5h	***	NS	–
Defecating (freq.)	0.7 ± 0.2	4.7 ± 0.5	***	0.7 ± 0.3	4.5 ± 0.4	***	NS	NS
Exploring treatment door (% of time)	0.5 ± 0.1	3.4 ± 0.7	***	0.4 ± 0.2	2.3 ± 0.6	***	+	NS
Ear posture
Ears back (% of time)	1.9 ± 0.7	17.3 ± 4.7	***	1.3 ± 0.5a	7.3 ± 2.0c	**	*	+
Tail postures
Tail in curl (% of time)	87.3 ± 3.5	99.8 ± 0.2	***	93.1 ± 2.4c	99.2 ± 0.7b	**	NS	+
Tail wagging (% of time)	12.3 ± 3.4	0.1 ± 0.0	***	6.7 ± 2.3c	0.2 ± 0.1b	***	+	+
Tail low (% of time)	0.4 ± 0.2	0.1 ± 0.1	NS	0.3 ± 0.2	0.6 ± 0.5	NS	NS	NS
Vocalizations (voc.)
Low-pitched voc. (freq.)	0.2 ± 0.2	24.8 ± 2.9	***
High-pitched voc. (% of pens)	0	50.0	**
Barks (% of pens)	87.5	0	***

Means with different superscript letters differ significantly (a/b/c: P < 0.05; g/h: P < 0.1)

¹Significance of effects of treatment (T), situation (S) and their interaction (TS) is indicated: *** P < 0.001; ** P < 0.01; * P < 0.05; ⁺ P < 0.10; NS P ≥ 0.10; – no statistical analysis performed

²These treatment effects belong to the first and second situations, respectively. Treatment effects over both situations were equal to the situation without naive pigs present

³The effect of situation within treatment was significant for urinating within the negative treatment, but not within the positive treatment nor for escape attempts and play