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Ethogram of pig behavior

 
Behavior Description
Balk Pig stops walking for more than 2 s
Turn around As it is being driven in 1 direction, pig turns around to go in opposite direction
Back up Pig walks at least 2 steps in reverse
Backward After turning around, pig walks in reverse for at least 2 steps
Vocalization Pig vocalizes
Underlap Pig lifts the 2 rear legs of another pig with its head
Overlap Pig mounts the back of another pig with its 2 front legs
Slip/fall Leg of the pig splits away from the other legs (slip) or at least 2 legs buckle under (fall)



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Frequencies of behaviors of pigs and interventions of the handler during loading onto a double-deck truck (DD) or pot-belly trailer (PB) during summer or winter

 
Summer
Winter
P-value
Item DD (n = 85)1 PB (n = 165)1 DD (n = 84)1 PB (n = 168)1 SE Truck Season Truck × season
Pig behavior
    Slip/fall 0.03 0.03 0.18 0.15 0.01 0.115 <0.001 0.068
    Overlap 0.10 0.09 0.05 0.05 0.01 0.510 <0.001 0.970
    180° turn 0.10 0.09 0.22 0.23 0.02 0.883 <0.001 0.669
    Back up 0.33 0.25 0.43 0.45 0.03 0.620 <0.001 0.039
    Backward 0.03 0.06 0.02 0.04 0.01 0.003 0.148 0.410
    Underlap 0.07 0.09 0.04 0.05 0.01 0.178 0.001 0.979
    Vocalize 0.20 0.26 0.38 0.36 0.03 0.115 <0.001 0.473
    Balk 0.76 0.60 0.17 0.20 0.03 0.107 <0.001 0.011
Intervention of handler
    Speaking 0.85 0.61 0.32 0.37 0.05 0.566 <0.001 0.012
    Whistling 0.07 0.09 0.002 0.005 0.01 0.195 <0.001 0.263
    Other vocal 0.47 0.38 0.003 0.04 0.03 0.929 <0.001 0.237
    Rattling 0.46 0.46 1.15 1.22 0.05 0.293 <0.001 0.392
    Pushing 0.30 0.25 0.15 0.19 0.04 0.616 <0.001 0.472
    Tapping 5.36 4.05 2.25 1.85 0.09 0.014 <0.001 0.602
1Number of groups loaded and observed. Values differ by season due to missing data.



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On-truck behavior (% of observations) in winter and summer during transport on the double-deck truck (DD) or pot-belly trailer (PB)

 
Truck
Season
P-value
Item DD (n = 43)1 PB (n = 71)1 Summer (n = 72)1 Winter (n = 42)1 SE Truck (T) Season T × season
Farm
    Standing 71.4 12.9 47.2 37.1 5.4 <0.001 0.186 0.688
    Sitting 24.1 63.1 41.2 46.0 4.2 <0.001 0.415 0.930
    Lying 3.9 23.1 9.7 17.3 3.6 <0.001 0.133 0.233
Transit
    Standing 56.1 36.6 42.6 50.0 3.5 <0.0001 0.138 0.407
    Sitting 38.1 50.3 44.0 44.5 1.5 <0.0001 0.821 0.101
    Lying 4.5 11.0 11.0 4.5 1.8 0.013 0.012 0.365
Arrival
    Standing 41.6 30.7 35.7 36.5 4.4 0.084 0.899 0.008
    Sitting 51.0 54.7 51.1 54.6 3.0 0.377 0.403 0.020
    Lying 4.3 16.2 16.4 4.1 3.7 0.025 0.022 0.006
1Number of compartments observed. Values differ by season due to missing data.



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Behavior of pigs (% of observations) by compartment during transport in summer (June, July) or winter (February, March) on the pot-belly trailer

 
Season
Compartment (Comp)
P-value
Item Summer Winter 1 3 4 5 6 8 9 10 SE Season Comp Season × Comp
Farm
    Standing 30.92 20.14 12.85 29.60 25.17 36.17 24.18 22.24 20.81 33.20 6.77 0.152 0.146 0.021
    Sitting 55.56 57.72 62.52 56.89 53.38 52.42 61.02 62.28 51.68 52.95 6.44 0.681 0.748 0.562
    Lying 13.21 22.86 23.67 12.34 16.89 10.58 13.75 27.32 26.25 13.46 6.03 0.041 0.243 0.088
Transit
    Standing 39.40 43.93 41.59ab 51.68a 28.43c 50.92a 31.79bc 50.09a 39.25b 35.58bc 4.31 0.225 <0.001 0.072
    Sitting 51.88 50.61 50.52ab 43.60b 62.44a 42.75b 61.79a 45.10b 47.75ab 56.00a 3.45 0.698 <0.001 0.051
    Lying 9.54 5.17 7.68 4.34 8.93 6.00 6.39 4.43 12.76 8.31 2.42 0.117 0.100 0.909
Arrival
    Standing 25.00 43.96 25.70 50.09 12.42 41.57 20.72 34.59 32.97 57.73 10.98 0.062 0.004 0.012
    Sitting 57.94 47.77 61.61 46.59 64.23 43.75 61.04 49.93 55.62 40.04 10.26 0.250 0.127 0.007
    Lying 16.35 8.31 12.70 3.14 21.31 14.10 18.37 15.47 11.41 2.15 7.69 0.226 0.232 0.103
    Unloadin time, sec/pig 2.92 3.20 3.28ab 3.28ab 3.82a 2.38c 3.01b 2.84b 2.80bc 3.11b 0.25 0.111 0.005 0.072
a−cWithin a row, means lacking a common superscripted letter differ (P < 0.05).



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Behavior1 during lairage (mean ± SE) in winter (February, March) and summer (June, July) after transport on the double-deck truck (DD) or pot-belly trailer (PB)

 
Season Lying Standing Sitting
Summer
    DD (n = 24)2 41.88 ± 2.79% 33.16 ± 1.85% 24.69 ± 1.64%
    PB (n = 48)2 51.13 ± 1.97% 24.39 ± 1.40% 24.32 ± 1.22%
Winter
    DD (n = 24)2 52.13 ± 2.79% 25.77 ± 1.85% 20.28 ± 1.64%
    PB (n = 48)2 45.29 ± 1.97% 25.03 ± 1.40% 27.56 ± 1.22%
P-value
    Season 0.362 0.025 0.664
    Truck (T) 0.617 0.002 0.011
    Season × T 0.001 0.008 0.005
1Percentages do not sum to 100% because a category of “other behavior” was included in observations (not included in the analyses).
2Number of lairage pens observed.