View Full Table | Close Full ViewTable 1.

Behaviors used to assess dyadic social relationships between sows

 
Category Behavior Description
Dominant
Feed restriction Sow defends feed and prevents other sow from eating
Bite Sow’s open mouth forcefully contacts other sow
Head knock Sow’s closed mouth forcefully contacts other sow
Bite threat With the mouth open or closed, sow thrusts head in the direction of other sow, often performed at a distance
Chase Sow rapidly follows fleeing sow
Subordinate
Retreat Sow flees from other sow
Keeps head averted Sow’s face is kept turned away from the other sow; eye contact is avoided
Turn head away Sow turns face away from other sow, often accompanied by lowering head
Lowering head Sow lowers head, usually to or below shoulder height
Stand behind Sow stands to the rear of other sow’s shoulders while eating



View Full Table | Close Full ViewTable 2.

Skin lesion scores1,2

 
Score Description
0 Normal
1 Reddening or callus
2 < 10 scratches and no cuts3
3 ≥ 10 scratches, < 5 cuts, 1 superficial wound, or 1 abscess
4 ≥ 5 cuts, 1 deep wound, > 1 superficial wound, or > 1 abscess
5 ≥ 10 cuts or ≥ 5 wounds
1Adapted from Hodgkiss et al. (1998) and Arey (1999).
2If lesions in one region met the criteria for more than 1 score, the greater of the 2 scores was assigned.
3A scratch had unbroken skin, a cut had broken skin < 2 cm in width and a wound had broken skin ≥ 2 cm in width.



View Full Table | Close Full ViewTable 3.

Sow social rank stability and BW by treatment and social rank1

 
Item Treatment2 P-value Social rank3
HCA Stable Mixed Companion High Middle Low P-value
Parity 1.9 ± 0.3 1.8 ± 0.3 2.2 ± 0.4 1.3 ± 0.3 0.15 2.4 ± 0.3a,x 1.7 ± 0.3y 1.4 ± 0.3b,y 0.009
Rank stability4 0.18 ± 0.08b 0.45 ± 0.08a,b 0.51 ± 0.11a,b 0.55 ± 0.07a 0.05
BW, kg
ED5 0 205.5 ± 5.6 200.0 ± 5.6 200.9 ± 7.8 184.8 ± 6.6 0.12 207.8 ± 5.2 193.4 ± 5.5 192.3 ± 6.7 0.09
ED 21 208.0 ± 5.5 207.1 ± 5.5 199.9 ± 8.0 195.6 ± 6.5 0.37 218.1 ± 5.4a 197.3 ± 5.5b 192.6 ± 6.7b 0.004
2 d post-farrowing 235.6 ± 6.1 234.1 ± 6.1 226.5 ± 8.1 216.6 ± 6.9 0.10 237.7 ± 5.8x 222.6 ± 5.9y 224.2 ± 7.0x,y 0.09
Weaning 218.9 ± 5.8 218.4 ± 5.8 216.5 ± 7.8 205.3 ± 6.5 0.27 222.9 ± 2.6 211.9 ± 5.6 209.5 ± 6.8 0.15
Δ BW, ED 0 to 21 2.6 ± 1.4b,c 6.8 ± 1.4a,b 0.2 ± 1.8c,d 10.6 ± 1.5a < 0.001 11.1 ± 1.2a 3.9 ± 1.2b 0.1 ± 1.5b < 0.001
Δ BW, lactation -16.6 ± 6.7 -16.3 ± 3.7 -11.7 ± 3.7 -10.6 ± 3.4 0.40 -13.6 ± 3.0 -12.0 ± 3.0 -15.8 ± 3.4 0.51
a–dLeast square means ± SE within the same row and main effect with different superscripts are different (P < 0.05).
x,yLeast square means ± SE within the same row and main effect with different superscripts tend to be different (0.05 ≤ P ≤ 0.10).
1The analyses used 27 HCA, 27 Stable, 18 Mixed, and 35 Companion sows and 41 high, 41 middle, and 25 low ranked sows.
2HCA = received 70 mg hydrocortisone acetate (HCA) twice daily; Stable = control group; Mixed = moved to new pen weekly; Companion = received a new pen mate weekly.
3Social rank was identified during feeding. High rank = sow dominant in both dyadic relationships; middle rank = sow dominant in 1 dyadic relationship; low rank = sow subordinate in both dyadic relationships (Table 1).
4Rank stability is the standard deviation of the social rank scores. Lower numbers indicate greater stability.
5ED = experimental day.



View Full Table | Close Full ViewTable 4.

Sow skin lesions1 by treatment and social rank2

 
Body region5 Treatment3 P-value Social rank4 P-value
HCA Stable Mixed Companion High Middle Low
Rump 3.35 ± 0.20 3.36 ± 0.16 3.70 ± 0.20 3.52 ± 0.19 0.35 3.27 ± 0.15 3.52 ± 0.17 3.66 ± 0.20 0.12
Upper leg 2.72 ± 0.16 2.68 ± 0.14 3.10 ± 0.10 3.08 ± 0.15 0.08 2.61 ± 0.09b 3.02 ± 0.10a 3.05 ± 0.13a < 0.001
Lower leg 2.37 ± 0.20 2.45 ± 0.18 2.66 ± 0.20 2.27 ± 0.16 0.40 2.31 ± 0.14 2.54 ± 0.16 2.47 ± 0.17 0.40
Hoof and toe 2.33 ± 0.16 2.49 ± 0.16 2.32 ± 0.15 2.50 ± 0.15 0.35 2.28 ± 0.13b 2.39 ± 0.13a,b 2.56 ± 0.14a 0.06
Dewclaw 2.14 ± 0.14 2.21 ± 0.12 2.13 ± 0.16 2.11 ± 0.16 0.96 2.04 ± 0.13 2.29 ± 0.04 2.18 ± 0.12 0.61
a,bLeast square means ± SE within the same row and main effect with different superscripts are different (P < 0.05).
1Higher lesions scores indicate more lesions and more severe lesions on a scale from 0 to 5 (Table 2).
2The analyses used 27 HCA, 27 Stable, 18 Mixed, and 35 Companion sows and 41 high, 41 middle, and 25 low ranked sows.
3HCA = received 70 mg hydrocortisone acetate (HCA) twice daily; Stable = control group; Mixed = moved to new pen weekly; Companion = received a new pen mate weekly.
4Social rank was identified during feeding. High rank = sow dominant in both dyadic relationships; middle rank = sow dominant in 1 dyadic relationship; low rank = sow subordinate in both dyadic relationships (Table 1).
5Rump lesions = rump, tail, and vulva and lower leg = hock, knee, and pasterns.



View Full Table | Close Full ViewTable 5.

Sow productivity and piglet measures by sow treatment and social rank1

 
Item Treatment2 P-value Social rank3 P-value
HCA Stable Mixed Companion high middle low
Gest length4, d 116.3 ± 0.2 116.3 ± 0.2 115.6 ± 0.5 115.6 ± 0.3 0.13 116.5 ± 0.3x 115.8 ± 0.3x,y 115.6 ± 0.3y 0.08
total no. born 10.74 ± 0.97 10.88 ± 0.95 10.58 ± 0.78 11.85 ± 0.76 0.74 12.39 ± 0.50x 10.35 ± 0.58y 10.30 ± 0.72y 0.03
Sex ratio5 1.38 ± 0.16 1.20 ± 0.16 1.12 ± 0.20 1.28 ± 0.14 0.80 1.02 ± 0.13 1.36 ± 0.14 1.35 ± 0.18 0.22
No. liveborn 9.65 ± 1.41 10.04 ± 1.30 9.88 ± 0.80 11.26 ± 0.83 0.70 11.26 ± 0.56 9.70 ± 0.68 9.67 ± 0.75 0.17
Sex ratio 1.42 ± 0.18 1.11 ± 0.17 0.98 ± 0.17 1.36 ± 0.13 0.23 0.98 ± 0.13 1.27 ± 0.13 1.40 ± 0.18 0.13
No. weaned 9.07 ± 0.64 8.53 ± 0.59 8.87 ± 0.70 9.67 ± 0.52 0.60 9.98 ± 0.45 8.69 ± 0.48 8.43 ± 0.64 0.11
Sex ratio 1.48 ± 0.22 1.32 ± 0.20 1.20 ± 0.26 1.67 ± 0.19 0.52 0.95 ± 0.17b 1.35 ± 0.18a,b 1.95 ± 0.23a 0.01
Born dead6, % 5.99 ± 1.76 5.78 ± 1.73 9.48 ± 3.45 6.14 ± 2.25 0.78 6.97 ± 1.93 7.64 ± 2.07 5.93 ± 2.44 0.88
a,bLeast square means ± SE within the same row and main effect with different superscripts are different (P < 0.05).
x,yLeast square means ± SE within the same row and main effect with different superscripts tend to be different (0.05 ≤ P ≤ 0.10).
1The analyses used 25 HCA, 26 Stable, 15 Mixed, and 35 Companion sows and 40 high, 40 middle, and 21 low ranked sows.
2HCA = received 70 mg hydrocortisone acetate (HCA) twice daily; Stable = control group; Mixed = moved to new pen weekly; Companion = received a new pen mate weekly.
3Social rank was identified during feeding. High rank = sow dominant in both dyadic relationships; middle rank = sow dominant in 1 dyadic relationship; low rank = sow subordinate in both dyadic relationships (Table 1).
4Gest length = gestation length.
5Sex ratio = number of males/number of females.
6Includes stillborn pigs and mummies.



View Full Table | Close Full ViewTable 6.

Body weight and ADG of male and female piglets by sow treatment1

 
Item3 Treatment2
HCA Stable Mixed Companion P-value
BW, kg ADG, g/d BW, kg ADG, g/d BW, kg ADG, g/d BW, kg ADG, g/d BW ADG
Birth 1.49 ± 0.04x,y
1.46 ± 0.04
1.54 ± 0.04x,y
1.50 ± 0.04
1.68 ± 0.08x
1.61 ± 0.08
1.42 ± 0.06y
1.38 ± 0.06
0.09
0.18
145.9 ± 15.8x
139.1 ± 17.7
166.5 ± 17.1a
147.8 ±18.1
132.5 ± 11.4a,b,x
157.4 ± 16.9
98.1 ± 11.5b,y
116.3 ± 17.1
0.02
0.40
d 3 1.8 ± 0.1
1.8 ± 0.1
1.9 ± 0.1
1.8 ± 0.1
1.9 ± 0.1
1.9 ± 0.1
1.7 ± 0.1
1.7 ± 0.1
0.09
0.66
181.7 ± 22.9
182.9 ± 18.2
180.9 ± 23.6
203.5 ± 18.4
192.0 ± 22.4
192.1 ± 28.2
186.3 ± 18.3
203.4 ± 14.2
0.99
0.82
d 7 2.5 ± 0.1
2.4 ± 0.1
2.6 ± 0.1
2.7 ± 0.1
2.7 ± 0.1
2.7 ± 0.2
2.5 ± 0.2
2.5 ± 0.1
0.48
0.33
271.2 ± 21.0
263.4 ± 13.7
236.1 ± 21.6
241.6 ± 14.2
259.3 ± 19.1
283.4 ± 17.2
246.5 ± 15.5
244.8 ± 10.1
0.67
0.22
d 14 4.5 ± 0.3
4.2 ± 0.2
4.3 ± 0.3
4.5 ± 0.2
4.6 ± 0.3
4.6 ± 0.3
4.1 ± 0.3
4.1 ± 0.2
0.70
0.19
236.8 ± 47.4
257.9 ± 16.5
292.2 ± 48.6
243.7 ± 17.2
267.2 ± 24.1
278.7 ± 22.7
239.9 ± 28.3
238.3 ± 14.3
0.81
0.49
Wean 5.6 ± 0.2
5.4 ± 0.2
5.7 ± 0.2
5.8 ± 0.2
5.9 ± 0.4
6.2 ± 0.4
5.8 ± 0.4
5.7 ± 0.2
0.92
0.42
686.5 ± 15.2
623.2 ± 16.5
634.7 ± 15.9
594.8 ± 16.85
660.8 ± 11.4
648.5 ± 19.1
655.1 ± 15.4
633.8 ± 13.1
0.17
0.20
d 160 105.5 ± 2.2a
96.6 ± 4.7
94.5 ± 2.5b
84.6 ± 4.7
100.0 ± 2.0a,b
89.4 ± 8.1
105.2 ± 3.8a,b
96.2 ± 1.8
0.02
0.26
a,bLeast square means ± SE in the same row with different superscripts are different (P < 0.05).
x,yLeast square means ± SE in the same row with different superscripts tend to be different (0.05 ≤ P ≤ 0.10).
1The analyses used 25 HCA, 23 Stable, 13 Mixed, and 33 Companion sows.
2HCA = received 70 mg hydrocortisone acetate (HCA) twice daily; Stable = control group; Mixed = moved to new pen weekly; Companion = received a new pen mate weekly.
3Body weights and ADG of the male piglets are listed above those of the female piglets.



View Full Table | Close Full ViewTable 7.

Reproductive morphology of male and female piglets by sow treatment and social rank1

 
Item Treatment2 P-value Social rank3 P-value
HCA Stable Mixed Companion High Middle Low
ANO4, mm/kg
Male 94.15 ± 1.60a,b 90.06 ± 1.50b,y 86.30 ± 3.08b,y 98.18 ± 2.49a,x 0.02 90.61 ± 1.87 92.11 ± 1.92 93.88 ± 2.46 0.59
Female 4.30 ± 0.11 4.45 ± 0.11 4.27 ± 0.23 4.35 ± 0.21 0.69 4.35 ± 0.15 4.31 ± 0.15 4.37 ± 0.19 0.96
Number teats
Male 14.49 ± 0.19 14.17 ± 0.19 14.28 ± 0.25 13.95 ± 0.20 0.24 14.52 ± 0.15 14.14 ± 0.15 14.01 ± 0.20 0.08
Female 14.47 ± 0.17 14.18 ± 0.17 14.25 ± 0.16 14.09 ± 0.14 0.41 14.31 ± 0.12 14.38 ± 0.12 14.05 ± 0.16 0.26
Rel testis wt5 × 10-3 0.93 ± 0.04 0.89 ± 0.04 0.97 ± 0.07 0.91 ± 0.03 0.78 0.92 ± 0.04 0.92 ± 0.04 0.93 ± 0.04 0.98
a,bLeast square means ± SE in the same row with different superscripts are different (P < 0.05).
x,yLeast square means ± SE in the same row with different superscripts tend to be different (0.05 ≤ P ≤ 0.10).
1The analyses used 25 HCA, 26 Stable, 15 Mixed, and 35 Companion sows and 40 high, 40 middle, and 21 low ranked sows.
2HCA = received 70 mg hydrocortisone acetate (HCA) twice daily; Stable = control group; Mixed = moved to new pen weekly; Companion = received a new pen mate weekly.
3Social rank was identified during feeding. High rank = sow dominant in both dyadic relationships; middle rank = sow dominant in 1 dyadic relationship; low rank = sow subordinate in both dyadic relationships (Table 1).
4ANO = relative anogenital distance calculated as anogenital distance, mm/pig BW, kg.
5Rel testis wt = relative testis weight calculated as mean testis weight, g/pig BW, kg.