Table 2.

Effect of litter origin on social network measures calculated using HWI ¹ of pigs at 6 and 8 weeks of age.

Item	Litter Origin			SE	p-Value
	Non-Littermates	Half-Group of Littermates	Littermates
# of pens	6	6	6
Pigs/pen	8	8	8
Time budget for lying posture, % of observation time
At 6 weeks of age	68.4	66.9	59.6	4.32	0.32
At 8 weeks of age	88.5	85.5	82.9	3.78	0.59
Social network measures
At 6 weeks of age
Pen level
Density 2	0.174 a	0.158 a,b	0.119 b	0.012	0.01
Distribution of ties3
Absent ties	12.0 a	16.5 a,b	19.8 b	1.66	0.01
Weak ties	14.2 a	9.3 a,b	6.2 b	1.25	0.002
Strong ties	1.8	2.2	2.0	0.06	0.92
Pig level
Strength	1.219 a	1.104 a	0.903 b	0.058	0.001
Eigenvector centrality	0.347	0.347	0.335	0.012	0.74
At 8 weeks of age
Pen level
Density	0.170 e	0.154 e,f	0.135 f	0.010	0.07
Distribution of ties
Absent ties	15.7	16.2	18.3	1.64	0.50
Weak ties	10.3	10.2	7.2	1.30	0.16
Strong ties	2.0	1.7	2.5	0.58	0.61
Pig level
Strength	1.188 a	1.075 a	0.943 b	0.006	0.001
Eigenvector centrality	0.355	0.344	0.346	0.012	0.76

¹ HWI = half-weight association index. ² Density = sum of HWI/28. ³ The number of each type (absent, weak, or strong) of ties. The number of possible ties was 28 for each pen of 8 pigs. ^a,b Least square means within a row without a common superscript differ (p < 0.05). ^e,f Least square means within a row without a common superscript tend to differ (p < 0.10).