Table 11.

Mean (± SE) of behavioral variables of paired piglets when subjected to a 10-min Social Challenge Test

Variable	Control n = 13 paired piglets	Medium n = 16 paired piglets	High n = 19 paired piglets
Activity latency, s	12.62 ± 2.70	26.47 ± 8.89	17.95 ± 3.61
Social interaction latency, s	27.46 ± 3.92	42.67 ± 11.46	36.05 ± 4.85
Contacts approaching the head, #	9.69 ± 0.84a	10.67 ± 1.09a	14.26 ± 1.11b
Contacts not approaching the head, #	21.85 ± 2.37	16.27 ± 2.05	18.42 ± 1.53
Nudges, #	2.46 ± 0.58	3.67 ± 0.87	4.37 ± 0.67
Latency to aggressive interactions, s	186.42 ± 26.42	194.73 ± 31.34	271.17 ± 42.72
Aggressive interactions, #	7.08 ± 1.53c,d	9.27 ± 1.45d	5.05 ± 0.92c
Total duration of aggressive interactions, s	42.62 ± 10.30	60.47 ± 13.78	32.68 ± 8.09
Time spent in proximity, s	571.23 ± 8.20	570.13 ± 5.60	569.21 ± 6.13
Escape attempts, #	0.08 ± 0.08	0.73 ± 0.36	0.53 ± 0.25

^a,

^b Means within a row with different superscripts differ (P < 0.02).

^c,

^d Means within a row with different superscripts tend to differ (P < 0.07).