TY - JOUR
AU - Gonyou, H. W.
AB - ABSTRACT Three experiments, each using 280 pigs, were conducted in a simulated compartment to test the effect of angle of entrance (AOE) to the ramp (90°, 60°, 30°, or 0°), ramp slope (0°, 16°, 21°, or 26°), and an initial 20-cm step associated with 16° or 21° ramp slopes on the ease of handling, heart rate (HR), and behavior of near market-weight pigs during unloading. Heart rate (pigs and handler), unloading time, interventions of the handler, and reactions of the pigs were monitored. The results of the first experiment show that using a 90° AOE had detrimental effects on ease of handling (P < 0.05), HR of the pig (P < 0.05), and behavior (P < 0.05). The 0° and 30° AOE appeared to improve the ease of unloading, whereas the 60° AOE had an intermediate effect. The 30° AOE appeared to be preferable, because pigs moved at this angle balked less frequently (P < 0.01) and required less manipulation (P < 0.05) than pigs moved with a 0° AOE. The results of the second experiment show that the use of a flat ramp led to the easiest unloading, as demonstrated by the lower number of balks (P < 0.001) when pigs were moved to the ramp and less frequent use of paddle (P = 0.001) or voice (P < 0.001) on the ramp, compared with the other treatments. However, the flat ramp did not differ from the 21° ramp in many of the variables reflecting ease of handling, which may be explained by the difference in configuration between the ramps. The results also show that the use of the steepest ramp slope had the most detrimental effect on balking and backing up behavior of pigs (P < 0.001), and handling (touches, slaps, and pushes; P < 0.05 for all) when moved to the ramp and on unloading time (P < 0.01). No differences in pig HR (P < 0.05) and ease of handling on the ramp (P < 0.05) were found between a 26° and 16° ramp slope, suggesting that the length of the ramp may be one of the factors that make unloading more difficult. The results of the last experiment show that an initial step made unloading physically more demanding for the handler (P < 0.001) and pigs on the ramp (P < 0.05) as demonstrated by their greater HR. The greater difficulty of handling (P < 0.01) and reluctance to move (P < 0.05) of pigs moved toward the 16° ramp with a step suggest that pigs perceived this ramp as more psychologically challenging. Making a few changes in terms of the design of the ramp could improve the efficiency of handling and reduce stress in pigs. INTRODUCTION Loading and unloading procedures have been identified as the most stressful events during the transport process (Grandin, 1997a; Warriss, 1998). Despite evidence about efficiency of the hydraulic lift or containers for loading groups of pigs onto the truck (Brown et al., 2005), loading for transport is still commonly performed with ramps in Canada. It has been shown that a ramp slope >20° leads to a significant increase in heart rate (Van Putten and Elshoff, 1978), cortisol concentration (Bradshaw et al., 1996), balking behavior (Phillips et al., 1988; Lambooij and Van Putten, 2000), and handling time (Warriss et al., 1991). Other ramp features, such as the presence and height of steps (Grandin, 1990), may affect the response of pigs during loading and unloading. The use of large, punch-hole trailers, such as “pot-belly” (PB) models, holding >200 pigs, is very common in Canada. Because these trailers are equipped with fixed upper and lower decks, external and internal ramps are used for loading. The use of ramps has been associated with greater mortality rates in Danish and British national transport surveys (Riches et al., 1996; Barton-Gade et al., 2007). In addition, steep internal ramps (up to 40°) and 90° turns within PB trailers are thought to increase unloading difficulty (Schwartzkopf-Genswein et al., 2012; Torrey et al., 2013), and can explain the greater incidence of dead and downers after transportation with a PB trailer, compared with a flat-deck trailer equipped with hydraulic decks (Ritter et al., 2008). There is a clear lack of knowledge on how ramp configuration may influence behavioral and physiological responses of pigs during loading or unloading. Therefore, the aim of this study was to determine the effect of different ramp configurations (ramp slope, an initial step and angle of entrance to the ramp) on handling, heart rate (HR), and behavior of near-market pigs unloaded from the lower compartment (the “pot”) of PB trailers. MATERIALS AND METHODS All experimental procedures performed in this study were approved by the University of Saskatchewan Animal Care Committee, which is regulated by the Canadian Council on Animal Care (Canadian Council on Animal Care, 2009). Animals and Treatment This study was undertaken at the Prairie Swine Centre Inc. (Saskatoon, SK, Canada). A total of 840 near-market pigs (cross between a L-42 sow and 337 boar; PIC Line), weighing ∼110 kg, were used in 3 experiments (280 animals/experiment). Pigs were housed in groups of 10 mixed-gender animals at a density of 0.85 m2/100 kg and had not been subjected to any handling besides weighing, nor were they previously exposed to a ramp. Each experiment was carried out in the same finishing room and trials occurred between 0830 and 1600 h. The room was temperature controlled (15°C) and uniformly illuminated, without any shadows in the experimental area. An experimental apparatus (Fig. 1) was constructed within the finishing barn and designed to simulate unloading from the PB compartment of a commercial transport trailer. It consisted of 2 holding pens connected by a ramp. The top pen (TP) had a metal floor [4.90 × 2.45 × 0.91 m; space allowance (SA) = 1.10 m2/100 kg] and was built on a hydraulic lift, which allowed pigs to be loaded into this area without using a ramp. During the test, TP was lifted to a height of 70 cm. The bottom pen (BP) had a concrete floor (1.75 × 2.45 × 0.91 m; SA = 0.39 m2/100 kg). Dimensions of BP, where all modifications to ramp configuration were made, were chosen because of their relevance to the typical design of the PB compartment. All ramps used in this project were custom built and measured 0.91 m wide, which provides enough room to allow 2 pigs to climb the ramp at the same time. The ramps were made of aluminum and cross laid with 2-cm-high cleats, spaced 10 cm apart. In the ramp area, 0.91-m-high wooden boxes were set on each side of the ramp to fill the gap between the 2 pens, thus delimiting the ramp area (Fig. 1). The ramps, which were covered in wood shavings, were centered in both pens, except for the 0° angle of entrance (Exp. 1; Fig. 2). For each experiment, 28 groups of 10 pigs were exposed to a specific ramp configuration (7 groups per treatment) on 7 nonconsecutive days. The exit ramp in the PB compartment was situated in the middle of the back wall to allow the compartment to extend as close as possible to the rear wheels. This location means that pigs approaching the exit along the wall must make a 90° turn to enter the ramp. In Exp. 1, the configuration of the ramp was changed by setting 0.91-m-high boards on one side of the entrance leading to the ramp to create angles of 90° (control), 60°, 30°, and 0°, into a 21° sloped loading ramp (1.95 m long). For each configuration, the BP space allowance was kept the same (0.39 m2/100 kg) by changing the dimensions of the pen (Fig. 2). In Exp. 2, 4 ramp slopes were tested: 0° (control), 16°, 21°, and 26° . Ramp lengths were 1.95, 2.54, 1.95, and 1.60 m, respectively. The control treatment consisted of a ramp laid on the horizontal floor. Thus, in this treatment, pigs had to go through a 91-cm-wide corridor with no elevation. Finally, in Exp. 3, 4 other ramp configurations were assessed: 16° or 21° ramp slope with or without a 20-cm initial step off the bottom of the ramp. The 16° and 21° ramps associated with a step measured 1.81 and 1.40 m long, respectively. Figure 1. View largeDownload slide Experimental room and apparatus. Figure 1. View largeDownload slide Experimental room and apparatus. Figure 2. View largeDownload slide Modification of the angle of entrance in the bottom pen (BP) and movement of the animals to the ramp. See online version for figure in color. Figure 2. View largeDownload slide Modification of the angle of entrance in the bottom pen (BP) and movement of the animals to the ramp. See online version for figure in color. Procedure Each group was submitted to a 6-h fasting period before the experiment and tested only once. For each trial, a group was moved from the home pen to TP and was held there for 15 min. The group was then moved from TP to BP, down the ramp (simulated loading), by the same handler using only a board, the voice, and a paddle. The unique handler used in this experiment was a trained technician who had experience in routine pig handling and transportation. In Exp. 1, the handler was specifically instructed to move the group of pigs by driving it to the modified entrance and holding a moving board on the other side of the ramp. As pigs were waiting in the BP for 10 min, the access to the ramp was closed by using a wooden board covering the ramp area to simulate the way it is done in a commercial trailer with a metal gate. Afterward, the board was removed and pigs were moved back up the ramp (simulated unloading), into the TP, and were given a 10-min rest period before being brought back to their home pen. The trial was stopped after 10 min, even if all pigs had not climbed up the ramp. Data Collection Pig Behavior and Ease of Handling The trials were video recorded using Optio W90 12.1 MP digital cameras (Pentax, Mississauga, ON, Canada) to monitor handling and behavior data in the BP and on the ramp. For each group, ease of moving pigs was assessed by recording the number of times the paddle was used by the handler to slap or touch a pig, or to make noise by hitting the floor or walls of the pen. The number of times the voice was used and a pig was pushed by the body of the handler or using a moving board was also monitored (Table 1). A subjective handling score was also used by asking the handler to assess the ease of handling by drawing a mark on a line ranging from very easy (0-cm mark) to very difficult to move (12-cm mark) at the end of each trial. The times taken to unload the first pig and the entire group were also recorded. A pig was considered as unloaded when its back legs were in the TP. The number of occurrences of each behavior described in Table 1 was recorded for each group. Table 1. Definitions of behavioral and handling variables Item  Description  Behavior        Vocalization  A sound (0.5 to 2 s) of both high amplitude and high frequency produced with an open mouth.      Back up  Pig backs up at least 2 steps.      Balks  Pig refuses to walk or stops for longer than 2 s.  Handling        Touch  Making contact with the back or side of the pig with a paddle when the paddle is not lifted above the height (0.9 cm) of pen sides.      Slap  Making contact with the back or side of the pig with a paddle when the paddle is raised above the height of pen sides before making contact.      Push  Handler applies pressure on pig with her body or a board (>2 s).      Noise  Voice: handler talks to encourage pigs to move.    Paddle: Handler hits the wall or floor with the paddle to make a noise (rattle) to encourage pigs to move.  Item  Description  Behavior        Vocalization  A sound (0.5 to 2 s) of both high amplitude and high frequency produced with an open mouth.      Back up  Pig backs up at least 2 steps.      Balks  Pig refuses to walk or stops for longer than 2 s.  Handling        Touch  Making contact with the back or side of the pig with a paddle when the paddle is not lifted above the height (0.9 cm) of pen sides.      Slap  Making contact with the back or side of the pig with a paddle when the paddle is raised above the height of pen sides before making contact.      Push  Handler applies pressure on pig with her body or a board (>2 s).      Noise  Voice: handler talks to encourage pigs to move.    Paddle: Handler hits the wall or floor with the paddle to make a noise (rattle) to encourage pigs to move.  View Large Table 1. Definitions of behavioral and handling variables Item  Description  Behavior        Vocalization  A sound (0.5 to 2 s) of both high amplitude and high frequency produced with an open mouth.      Back up  Pig backs up at least 2 steps.      Balks  Pig refuses to walk or stops for longer than 2 s.  Handling        Touch  Making contact with the back or side of the pig with a paddle when the paddle is not lifted above the height (0.9 cm) of pen sides.      Slap  Making contact with the back or side of the pig with a paddle when the paddle is raised above the height of pen sides before making contact.      Push  Handler applies pressure on pig with her body or a board (>2 s).      Noise  Voice: handler talks to encourage pigs to move.    Paddle: Handler hits the wall or floor with the paddle to make a noise (rattle) to encourage pigs to move.  Item  Description  Behavior        Vocalization  A sound (0.5 to 2 s) of both high amplitude and high frequency produced with an open mouth.      Back up  Pig backs up at least 2 steps.      Balks  Pig refuses to walk or stops for longer than 2 s.  Handling        Touch  Making contact with the back or side of the pig with a paddle when the paddle is not lifted above the height (0.9 cm) of pen sides.      Slap  Making contact with the back or side of the pig with a paddle when the paddle is raised above the height of pen sides before making contact.      Push  Handler applies pressure on pig with her body or a board (>2 s).      Noise  Voice: handler talks to encourage pigs to move.    Paddle: Handler hits the wall or floor with the paddle to make a noise (rattle) to encourage pigs to move.  View Large Heart Rate Pigs to be used for the HR study were selected using an Open Door Test (adapted from Brown et al., 2009), 1 wk before the trial. This test was used to assess HR across various coping strategies (proactive, intermediate, and reactive). Just before performing the test, a person entered the home pen to mark the pigs from 1 to 10 to identify them during the test. The pen door was then opened by the observer from a distance of 1 m away from the pen entrance. Over a 3-min period, pigs were free to leave the pen and go into a hallway. For each pig, the latency to get out of the pen (hind feet crossing pen entrance) was recorded. Pigs received a rank (from 1 to 10) according to their latency to exit. Pigs that did not exit the pen got the maximum latency (180 s) and were scored as last (rank 10). The first, fifth, and last pig were selected to be fitted with HR monitors. Heart rates were recorded throughout all trials at 5-s intervals in the handler and 3 pigs from each group, using Polar heart rate monitors (Polar Electro Canada Inc., Quebec, Canada). Each HR monitor was inserted into the protective pouch of a rubber belt that was fitted around both the chest of the pigs and chest of the handler, with an elastic belt. The thoracic region of each pig was shaved and a lubricant gel was applied to the sensors to ensure connection was maintained with the skin. After fitting the HR monitors, pigs were returned to their home pen for 60 min to allow HR to return to a normal resting level. Data were downloaded and the average HR for each pig was determined for each of the experimental periods, which were the 10-min holding periods before unloading (waiting period), unloading period (in BP and on the ramp), and the 10-min recovery period after unloading. For the analysis, the increase in HR in BP (HRBP – HRwaiting period) and on the ramp (HRramp – HRBP), along with the decrease in HR in TP (HRrecovery period – HRramp), were calculated and expressed as a percentage. For the handler, the increase in HR was calculated as: HRtest – HRrest, with HRtest and HRrest being respectively the HR of the handler during the test and 5 min before the test started, as the handler was resting. Statistical Analysis Each experiment was designed as a randomized complete block design. A replicate consisted of 4 trials including every treatment. The group of 10 pigs tested on a given ramp configuration was considered the experimental unit. This design allowed each group of pigs to be subjected to a given ramp slope in a balanced order across and within days, controlling for the effect of time of day and experimental day. Normality and homogeneity of variance (Shapiro-Wilk test) were tested before the analysis. For experiments 1 and 2, heart rate (average of the heart rates of the 3 selected pigs), subjective handling score, and unloading time were analyzed as 4 treatment factors by ANOVA using the PROC MIXED procedure (SAS Inst. Inc., Cary, NC), whereas for the experiment 3, they were analyzed as a 2 × 2 factorial (presence or absence of the step and 16° or 21° slope). A correlation analysis was carried out between the subjective handling score and HR of the handler, using the PROC CORR procedure in SAS. Ramp configuration was treated as a fixed effect, whereas the day effect was considered as random. Tukey-Kramer adjustments were used to compare treatment means. When residual normality was not met, transformations using the BOXCOX procedure in SAS were performed. Behavioral and handling data were averaged for the group of pigs and analyzed using the Kruskal-Wallis 1-way ANOVA. A Mann-Whitney test was used, if the previous test was significant, to compare treatment means. Untransformed LS means and SEM are reported. A probability level of P < 0.05 was chosen as the limit for statistical significance in all tests, while a probability level of 0.1 < P < 0.05 was chosen to describe a tendency. RESULTS Experiment 1 (Angle of Entrance to the Ramp) Heart Rate The increase in HR of the handler was less (P = 0.018) when a 0° angle of entrance was used compared with a 90° angle, whereas HR values for 30° and 60° angles were intermediate and did not differ (P > 0.05) from the other treatments (Table 2). Pigs in the 90° angle of entrance treatment had the greatest (P = 0.019) increase in HR in the BP and a greater increase (P = 0.011) in HR on the ramp than those in the 30° or 60° treatments, whereas pigs in the 0° angle treatment were intermediate on the ramp and did not differ (P > 0.05) from the other treatments (Table 2). There were no differences (P > 0.05) in HR among the 4 treatments when pigs were in the top pen. Table 2. Effects of angle of entrance on heart rate (HR), pig behavior, and ease of handling (LS mean ± SEM) during simulated unloading   Angle of entrance  Item  0°  30°  60°  90°  P-value  HR, %      Handler1  +32.2 ± 3.2b  +36.9 ± 3.2ab  +36.2 ± 3.2ab  +47.4 ± 3.2a  0.018      Pigs in BP2,3  +24.4 ± 1.2b  +25.6 ± 1.2b  +24.0 ± 1.2b  +34.9 ± 1.2a  0.019      Pigs on ramp4  +11.2 ± 1.6ab  +7.1 ± 1.6b  +7.5 ± 1.6b  +14.2 ± 1.6a  0.011      Pigs in TP5,6  –14.5 ± 2.8  –15.6 ± 2.8  –16.3 ± 2.8  –20.5 ± 2.8  0.698  Behavior, occurrences per loading event7      In BP2                    Balks  6.0 ± 0.8b  1.9 ± 0.5c  6.0 ± 1.9b  22.3 ± 7.0a  0.007          Back up  1.1 ± 0.5  0.3 ± 0.3  1.6 ± 0.6  1.7 ± 0.8  0.191          Vocalizations  2.4 ± 0.9b  1.1 ± 0.6b  1.0 ± 0.2b  7.7 ± 1.7a  0.045      On ramp8          Balks  5.1 ± 0.5b  3.3 ± 0.3c  9.6 ± 0.6ab  14.4 ± 0.8a  0.009  Unloading time,9 s      First pig  30.7 ± 13.5b  21.9 ± 13.5b  32.9 ± 13.5b  70.0 ± 13.5a  0.018      Group  143.2 ± 59.2b  131.3 ± 59.2b  152.1 ± 59.2b  330.7 ± 59.2a  0.034  Handling, occurrences per loading event7      In BP2                    Voice  13.6 ± 3.2b  6.7 ± 1.6b  19.6 ± 4.3a  28.0 ± 6.0a  0.015          Noise with paddle  29.3 ± 5.6a  18.6 ± 3.1b  46.0 ± 12.8a  52.9 ± 12.7a  0.044          Touch/slap  8.1 ± 2.1b  0.9 ± 0.3c  7.0 ± 2.9b  23.1 ± 4.0a  0.043          Push  7.1 ± 1.7b  2.0 ± 0.4c  7.3 ± 2.0b  17.9 ± 5.0a  0.047      On ramp          Voice  2.0 ± 0.9  2.1 ± 1.0  2.9 ± 0.9  4.9 ± 1.3  0.201          Noise with paddle  5.7 ± 1.9  4.6 ± 2.1  6.4 ± 1.6  17.7 ± 11.7  0.499          Touch/slap  5.1 ± 1.9  0.3 ± 0.3  5.0 ± 2.3  4.7 ± 2.4  0.121          Push  1.6 ± 1.3  1.0 ± 0.6  2.4 ± 1.4  4.4 ± 1.3  0.206  SHS,9,10 cm  2.1 ± 1.2  1.3 ± 1.2  2.8 ± 1.2  4.4 ± 1.2  0.285    Angle of entrance  Item  0°  30°  60°  90°  P-value  HR, %      Handler1  +32.2 ± 3.2b  +36.9 ± 3.2ab  +36.2 ± 3.2ab  +47.4 ± 3.2a  0.018      Pigs in BP2,3  +24.4 ± 1.2b  +25.6 ± 1.2b  +24.0 ± 1.2b  +34.9 ± 1.2a  0.019      Pigs on ramp4  +11.2 ± 1.6ab  +7.1 ± 1.6b  +7.5 ± 1.6b  +14.2 ± 1.6a  0.011      Pigs in TP5,6  –14.5 ± 2.8  –15.6 ± 2.8  –16.3 ± 2.8  –20.5 ± 2.8  0.698  Behavior, occurrences per loading event7      In BP2                    Balks  6.0 ± 0.8b  1.9 ± 0.5c  6.0 ± 1.9b  22.3 ± 7.0a  0.007          Back up  1.1 ± 0.5  0.3 ± 0.3  1.6 ± 0.6  1.7 ± 0.8  0.191          Vocalizations  2.4 ± 0.9b  1.1 ± 0.6b  1.0 ± 0.2b  7.7 ± 1.7a  0.045      On ramp8          Balks  5.1 ± 0.5b  3.3 ± 0.3c  9.6 ± 0.6ab  14.4 ± 0.8a  0.009  Unloading time,9 s      First pig  30.7 ± 13.5b  21.9 ± 13.5b  32.9 ± 13.5b  70.0 ± 13.5a  0.018      Group  143.2 ± 59.2b  131.3 ± 59.2b  152.1 ± 59.2b  330.7 ± 59.2a  0.034  Handling, occurrences per loading event7      In BP2                    Voice  13.6 ± 3.2b  6.7 ± 1.6b  19.6 ± 4.3a  28.0 ± 6.0a  0.015          Noise with paddle  29.3 ± 5.6a  18.6 ± 3.1b  46.0 ± 12.8a  52.9 ± 12.7a  0.044          Touch/slap  8.1 ± 2.1b  0.9 ± 0.3c  7.0 ± 2.9b  23.1 ± 4.0a  0.043          Push  7.1 ± 1.7b  2.0 ± 0.4c  7.3 ± 2.0b  17.9 ± 5.0a  0.047      On ramp          Voice  2.0 ± 0.9  2.1 ± 1.0  2.9 ± 0.9  4.9 ± 1.3  0.201          Noise with paddle  5.7 ± 1.9  4.6 ± 2.1  6.4 ± 1.6  17.7 ± 11.7  0.499          Touch/slap  5.1 ± 1.9  0.3 ± 0.3  5.0 ± 2.3  4.7 ± 2.4  0.121          Push  1.6 ± 1.3  1.0 ± 0.6  2.4 ± 1.4  4.4 ± 1.3  0.206  SHS,9,10 cm  2.1 ± 1.2  1.3 ± 1.2  2.8 ± 1.2  4.4 ± 1.2  0.285  a–cWithin a row, means without a common superscript differ (P < 0.05). 1Difference between HRtest and H rest. 2BP = bottom pen. 3Difference between HRBP and HRwaiting period. 4Difference between HRramp and HRBP. 5TP = top pen. 6Difference between HRrecovery period and HRramp. 7Analyzed using Kruskal-Wallis one-way analysis of variance. 8Not enough data to run the analysis on back up and vocalizations. 9Probabilities after log transformation. 10SHS = subjective handling score (cm; 0 cm = very easy; 12 cm = very difficult). View Large Table 2. Effects of angle of entrance on heart rate (HR), pig behavior, and ease of handling (LS mean ± SEM) during simulated unloading   Angle of entrance  Item  0°  30°  60°  90°  P-value  HR, %      Handler1  +32.2 ± 3.2b  +36.9 ± 3.2ab  +36.2 ± 3.2ab  +47.4 ± 3.2a  0.018      Pigs in BP2,3  +24.4 ± 1.2b  +25.6 ± 1.2b  +24.0 ± 1.2b  +34.9 ± 1.2a  0.019      Pigs on ramp4  +11.2 ± 1.6ab  +7.1 ± 1.6b  +7.5 ± 1.6b  +14.2 ± 1.6a  0.011      Pigs in TP5,6  –14.5 ± 2.8  –15.6 ± 2.8  –16.3 ± 2.8  –20.5 ± 2.8  0.698  Behavior, occurrences per loading event7      In BP2                    Balks  6.0 ± 0.8b  1.9 ± 0.5c  6.0 ± 1.9b  22.3 ± 7.0a  0.007          Back up  1.1 ± 0.5  0.3 ± 0.3  1.6 ± 0.6  1.7 ± 0.8  0.191          Vocalizations  2.4 ± 0.9b  1.1 ± 0.6b  1.0 ± 0.2b  7.7 ± 1.7a  0.045      On ramp8          Balks  5.1 ± 0.5b  3.3 ± 0.3c  9.6 ± 0.6ab  14.4 ± 0.8a  0.009  Unloading time,9 s      First pig  30.7 ± 13.5b  21.9 ± 13.5b  32.9 ± 13.5b  70.0 ± 13.5a  0.018      Group  143.2 ± 59.2b  131.3 ± 59.2b  152.1 ± 59.2b  330.7 ± 59.2a  0.034  Handling, occurrences per loading event7      In BP2                    Voice  13.6 ± 3.2b  6.7 ± 1.6b  19.6 ± 4.3a  28.0 ± 6.0a  0.015          Noise with paddle  29.3 ± 5.6a  18.6 ± 3.1b  46.0 ± 12.8a  52.9 ± 12.7a  0.044          Touch/slap  8.1 ± 2.1b  0.9 ± 0.3c  7.0 ± 2.9b  23.1 ± 4.0a  0.043          Push  7.1 ± 1.7b  2.0 ± 0.4c  7.3 ± 2.0b  17.9 ± 5.0a  0.047      On ramp          Voice  2.0 ± 0.9  2.1 ± 1.0  2.9 ± 0.9  4.9 ± 1.3  0.201          Noise with paddle  5.7 ± 1.9  4.6 ± 2.1  6.4 ± 1.6  17.7 ± 11.7  0.499          Touch/slap  5.1 ± 1.9  0.3 ± 0.3  5.0 ± 2.3  4.7 ± 2.4  0.121          Push  1.6 ± 1.3  1.0 ± 0.6  2.4 ± 1.4  4.4 ± 1.3  0.206  SHS,9,10 cm  2.1 ± 1.2  1.3 ± 1.2  2.8 ± 1.2  4.4 ± 1.2  0.285    Angle of entrance  Item  0°  30°  60°  90°  P-value  HR, %      Handler1  +32.2 ± 3.2b  +36.9 ± 3.2ab  +36.2 ± 3.2ab  +47.4 ± 3.2a  0.018      Pigs in BP2,3  +24.4 ± 1.2b  +25.6 ± 1.2b  +24.0 ± 1.2b  +34.9 ± 1.2a  0.019      Pigs on ramp4  +11.2 ± 1.6ab  +7.1 ± 1.6b  +7.5 ± 1.6b  +14.2 ± 1.6a  0.011      Pigs in TP5,6  –14.5 ± 2.8  –15.6 ± 2.8  –16.3 ± 2.8  –20.5 ± 2.8  0.698  Behavior, occurrences per loading event7      In BP2                    Balks  6.0 ± 0.8b  1.9 ± 0.5c  6.0 ± 1.9b  22.3 ± 7.0a  0.007          Back up  1.1 ± 0.5  0.3 ± 0.3  1.6 ± 0.6  1.7 ± 0.8  0.191          Vocalizations  2.4 ± 0.9b  1.1 ± 0.6b  1.0 ± 0.2b  7.7 ± 1.7a  0.045      On ramp8          Balks  5.1 ± 0.5b  3.3 ± 0.3c  9.6 ± 0.6ab  14.4 ± 0.8a  0.009  Unloading time,9 s      First pig  30.7 ± 13.5b  21.9 ± 13.5b  32.9 ± 13.5b  70.0 ± 13.5a  0.018      Group  143.2 ± 59.2b  131.3 ± 59.2b  152.1 ± 59.2b  330.7 ± 59.2a  0.034  Handling, occurrences per loading event7      In BP2                    Voice  13.6 ± 3.2b  6.7 ± 1.6b  19.6 ± 4.3a  28.0 ± 6.0a  0.015          Noise with paddle  29.3 ± 5.6a  18.6 ± 3.1b  46.0 ± 12.8a  52.9 ± 12.7a  0.044          Touch/slap  8.1 ± 2.1b  0.9 ± 0.3c  7.0 ± 2.9b  23.1 ± 4.0a  0.043          Push  7.1 ± 1.7b  2.0 ± 0.4c  7.3 ± 2.0b  17.9 ± 5.0a  0.047      On ramp          Voice  2.0 ± 0.9  2.1 ± 1.0  2.9 ± 0.9  4.9 ± 1.3  0.201          Noise with paddle  5.7 ± 1.9  4.6 ± 2.1  6.4 ± 1.6  17.7 ± 11.7  0.499          Touch/slap  5.1 ± 1.9  0.3 ± 0.3  5.0 ± 2.3  4.7 ± 2.4  0.121          Push  1.6 ± 1.3  1.0 ± 0.6  2.4 ± 1.4  4.4 ± 1.3  0.206  SHS,9,10 cm  2.1 ± 1.2  1.3 ± 1.2  2.8 ± 1.2  4.4 ± 1.2  0.285  a–cWithin a row, means without a common superscript differ (P < 0.05). 1Difference between HRtest and H rest. 2BP = bottom pen. 3Difference between HRBP and HRwaiting period. 4Difference between HRramp and HRBP. 5TP = top pen. 6Difference between HRrecovery period and HRramp. 7Analyzed using Kruskal-Wallis one-way analysis of variance. 8Not enough data to run the analysis on back up and vocalizations. 9Probabilities after log transformation. 10SHS = subjective handling score (cm; 0 cm = very easy; 12 cm = very difficult). View Large Pig Behavior Pigs in 90° angle of entrance treatment balked the most (P = 0.007), whereas those in the 30° treatment balked the least (Table 2). There were no differences (P > 0.05) between the 0° and 60° angle of entrance treatments. Vocalizations were the most frequent (P = 0.045) with the 90° angle treatment (Table 2), whereas there was no difference (P > 0.05) among the other treatments. On the ramp, the number of balking events was the greatest (P = 0.009) for pigs in the 90° angle treatment and lowest for pigs in the 0° and 30° angle treatments (Table 2), whereas it did not differ (P > 0.05) among pigs in the 60° treatment and those in the 30 or 90° treatments. The frequency of backup behavior was not significantly (P > 0.05) affected by the angle of entrance. Ease of Handling It took longer (P = 0.018 and P = 0.034, respectively) to unload the first pig and the group (Table 2) for pigs in the 90° angle of entrance treatment. The subjective handling score, positively and moderately correlated (R = 0.492; P = 0.008) with HR of the handler, did not differ (P > 0.05) among the 4 treatments. In BP, the handler used voice less frequently (P = 0.015) to move pigs in the 0° or 30° angle of entrance treatments than toward 60° or 90° angle treatments (Table 2). Using the paddle to make noise was found to be the lowest (P = 0.044) to move pigs in the 30° angle treatment. There were no differences (P > 0.05) among the 3 other treatments (Table 2). The number of touches, slaps, and pushes was greatest (P = 0.043 and P = 0.047, respectively) for pigs in the 90° angle treatment and lowest for those in the 30° angle treatment (Table 2). There were no differences (P > 0.05) between pigs in the 0° and 60° angle of entrance treatments. No differences were found for all handling measures on the ramp. Experiment 2 (Ramp Slope) Heart Rate The increase in HR of the handler was the greatest (P < 0.001) when pigs were unloaded using the 26° ramp and least with the 0° ramp (Table 3). There were no differences (P > 0.05) between the 16° and the 21° ramps. When pigs were being moved toward the ramp and on the ramp, their increase in HR (P < 0.001 and P = 0.022, respectively) was the least with the 0° and 21° ramps and greatest with the 16° and 26° ramps (Table 3). After unloading (in TP), the decrease in HR was greater (P = 0.003) in pigs moved through the 26° ramp than those moved through 0° and 21° ramps (Table 3). No differences (P > 0.05) were found between the 16° and the 0° ramps or between the 16° and 26° ramps. Table 3. Effects of ramp slope on heart rate (HR), pig behavior, and ease of handling (mean ± SEM) during simulated unloading   Ramp slope  Item  0°  16°  21°  26°  P-value  HR, %      Handler1  +18.8 ± 2.3c  +30.6 ± 2.3b  +30.9 ± 2.3b  +39.6 ± 2.3a  <0.001      Pigs in BP2,3  +22.1 ± 2.2b  +30.3 ± 2.2a  +23.1 ± 2.2b  +33.2 ± 2.2a  <0.001      Pigs on ramp4  +7.2 ± 1.1b  +11.4 ± 1.1a  +6.6 ± 1.1b  +12.6 ± 1.1a  0.022      Pigs in TP5,6  –13.1 ± 2.9bc  –19.9 ± 2.9ab  –11.2 ± 2.9c  –26.7 ± 2.9a  0.003  Behavior, occurrences per loading event7      In BP2                    Balks  1.3 ± 0.5c  8.9 ± 2.3b  6.6 ± 1.6b  24.4 ± 6.2a  <0.001          Back up  0.0 ± 0.0b  0.7 ± 0.3b  0.4 ± 0.3b  5.1 ± 0.9a  <0.001          Vocalizations  1.0 ± 0.7b  1.1 ± 0.6b  1.3 ± 0.6b  11.6 ± 2.4a  0.002      On ramp8          Balks  2.7 ± 1.2b  14.4 ± 2.6a  5.6 ± 1.2b  14.9 ± 5.2a  0.004  Unloading time,9 s      First pig  20.7 ± 12.8b  28.3 ± 12.8b  35.1 ± 12.8b  78.6 ± 12.8a  0.006      Group  136.3 ± 42.1b  238.4 ± 42.1b  172.1 ± 42.1b  413.4 ± 42.1a  <0.001  Handling, occurrences per loading event7      In BP2                    Voice  7.1 ± 1.8b  26.3 ± 5.2a  11.0 ± 1.8b  43.7 ± 7.6a  0.002          Noise with paddle  21.0 ± 7.0b  107.0 ± 26.9a  36.9 ± 9.0b  105.9 ± 12.7a  0.006          Touch/slap  3.3 ± 1.6b  6.4 ± 2.0b  1.9 ± 1.0b  48.3 ± 20.0a  0.010          Push  0.1 ± 0.1b  1.1 ± 0.6b  0.4 ± 0.3b  16.1 ± 4.1a  0.045      On ramp          Voice  1.6 ± 0.7c  11.4 ± 2.3a  5.4 ± 0.8b  16.1 ± 3.0a  0.001          Noise with paddle  2.6 ± 1.1c  48.6 ± 10.6a  11.4 ± 2.2b  22.6 ± 7.2a  <0.001          Touch/slap  0.1 ± 0.1c  3.29 ± 2.8b  1.3 ± 0.6bc  11.0 ± 4.2a  0.044          Push  0.0 ± 0.0b  2.4 ± 0.8a  0.1 ± 0.1b  8.0 ± 4.1a  0.002  SHS,9,10 cm  0.3 ± 0.8c  2.9 ± 0.8b  0.6 ± 0.8c  6.2 ± 0.8a  <0.001    Ramp slope  Item  0°  16°  21°  26°  P-value  HR, %      Handler1  +18.8 ± 2.3c  +30.6 ± 2.3b  +30.9 ± 2.3b  +39.6 ± 2.3a  <0.001      Pigs in BP2,3  +22.1 ± 2.2b  +30.3 ± 2.2a  +23.1 ± 2.2b  +33.2 ± 2.2a  <0.001      Pigs on ramp4  +7.2 ± 1.1b  +11.4 ± 1.1a  +6.6 ± 1.1b  +12.6 ± 1.1a  0.022      Pigs in TP5,6  –13.1 ± 2.9bc  –19.9 ± 2.9ab  –11.2 ± 2.9c  –26.7 ± 2.9a  0.003  Behavior, occurrences per loading event7      In BP2                    Balks  1.3 ± 0.5c  8.9 ± 2.3b  6.6 ± 1.6b  24.4 ± 6.2a  <0.001          Back up  0.0 ± 0.0b  0.7 ± 0.3b  0.4 ± 0.3b  5.1 ± 0.9a  <0.001          Vocalizations  1.0 ± 0.7b  1.1 ± 0.6b  1.3 ± 0.6b  11.6 ± 2.4a  0.002      On ramp8          Balks  2.7 ± 1.2b  14.4 ± 2.6a  5.6 ± 1.2b  14.9 ± 5.2a  0.004  Unloading time,9 s      First pig  20.7 ± 12.8b  28.3 ± 12.8b  35.1 ± 12.8b  78.6 ± 12.8a  0.006      Group  136.3 ± 42.1b  238.4 ± 42.1b  172.1 ± 42.1b  413.4 ± 42.1a  <0.001  Handling, occurrences per loading event7      In BP2                    Voice  7.1 ± 1.8b  26.3 ± 5.2a  11.0 ± 1.8b  43.7 ± 7.6a  0.002          Noise with paddle  21.0 ± 7.0b  107.0 ± 26.9a  36.9 ± 9.0b  105.9 ± 12.7a  0.006          Touch/slap  3.3 ± 1.6b  6.4 ± 2.0b  1.9 ± 1.0b  48.3 ± 20.0a  0.010          Push  0.1 ± 0.1b  1.1 ± 0.6b  0.4 ± 0.3b  16.1 ± 4.1a  0.045      On ramp          Voice  1.6 ± 0.7c  11.4 ± 2.3a  5.4 ± 0.8b  16.1 ± 3.0a  0.001          Noise with paddle  2.6 ± 1.1c  48.6 ± 10.6a  11.4 ± 2.2b  22.6 ± 7.2a  <0.001          Touch/slap  0.1 ± 0.1c  3.29 ± 2.8b  1.3 ± 0.6bc  11.0 ± 4.2a  0.044          Push  0.0 ± 0.0b  2.4 ± 0.8a  0.1 ± 0.1b  8.0 ± 4.1a  0.002  SHS,9,10 cm  0.3 ± 0.8c  2.9 ± 0.8b  0.6 ± 0.8c  6.2 ± 0.8a  <0.001  a–cWithin a row, means without a common superscript differ (P < 0.05). 1Difference between HRtest and HRrest. 2BP = bottom pen. 3Difference between HRBP and HRwaiting period. 4Difference between HRramp and HRBP. 5TP = top pen. 6Difference between HRrecovery period and HRramp. 7Analyzed using Kruskal-Wallis one-way analysis of variance. 8Not enough data to run the analysis on back up and vocalizations. 9Probabilities after log transformation. 10SHS = subjective handling score (cm; 0 cm = very easy; 12 cm = very difficult). View Large Table 3. Effects of ramp slope on heart rate (HR), pig behavior, and ease of handling (mean ± SEM) during simulated unloading   Ramp slope  Item  0°  16°  21°  26°  P-value  HR, %      Handler1  +18.8 ± 2.3c  +30.6 ± 2.3b  +30.9 ± 2.3b  +39.6 ± 2.3a  <0.001      Pigs in BP2,3  +22.1 ± 2.2b  +30.3 ± 2.2a  +23.1 ± 2.2b  +33.2 ± 2.2a  <0.001      Pigs on ramp4  +7.2 ± 1.1b  +11.4 ± 1.1a  +6.6 ± 1.1b  +12.6 ± 1.1a  0.022      Pigs in TP5,6  –13.1 ± 2.9bc  –19.9 ± 2.9ab  –11.2 ± 2.9c  –26.7 ± 2.9a  0.003  Behavior, occurrences per loading event7      In BP2                    Balks  1.3 ± 0.5c  8.9 ± 2.3b  6.6 ± 1.6b  24.4 ± 6.2a  <0.001          Back up  0.0 ± 0.0b  0.7 ± 0.3b  0.4 ± 0.3b  5.1 ± 0.9a  <0.001          Vocalizations  1.0 ± 0.7b  1.1 ± 0.6b  1.3 ± 0.6b  11.6 ± 2.4a  0.002      On ramp8          Balks  2.7 ± 1.2b  14.4 ± 2.6a  5.6 ± 1.2b  14.9 ± 5.2a  0.004  Unloading time,9 s      First pig  20.7 ± 12.8b  28.3 ± 12.8b  35.1 ± 12.8b  78.6 ± 12.8a  0.006      Group  136.3 ± 42.1b  238.4 ± 42.1b  172.1 ± 42.1b  413.4 ± 42.1a  <0.001  Handling, occurrences per loading event7      In BP2                    Voice  7.1 ± 1.8b  26.3 ± 5.2a  11.0 ± 1.8b  43.7 ± 7.6a  0.002          Noise with paddle  21.0 ± 7.0b  107.0 ± 26.9a  36.9 ± 9.0b  105.9 ± 12.7a  0.006          Touch/slap  3.3 ± 1.6b  6.4 ± 2.0b  1.9 ± 1.0b  48.3 ± 20.0a  0.010          Push  0.1 ± 0.1b  1.1 ± 0.6b  0.4 ± 0.3b  16.1 ± 4.1a  0.045      On ramp          Voice  1.6 ± 0.7c  11.4 ± 2.3a  5.4 ± 0.8b  16.1 ± 3.0a  0.001          Noise with paddle  2.6 ± 1.1c  48.6 ± 10.6a  11.4 ± 2.2b  22.6 ± 7.2a  <0.001          Touch/slap  0.1 ± 0.1c  3.29 ± 2.8b  1.3 ± 0.6bc  11.0 ± 4.2a  0.044          Push  0.0 ± 0.0b  2.4 ± 0.8a  0.1 ± 0.1b  8.0 ± 4.1a  0.002  SHS,9,10 cm  0.3 ± 0.8c  2.9 ± 0.8b  0.6 ± 0.8c  6.2 ± 0.8a  <0.001    Ramp slope  Item  0°  16°  21°  26°  P-value  HR, %      Handler1  +18.8 ± 2.3c  +30.6 ± 2.3b  +30.9 ± 2.3b  +39.6 ± 2.3a  <0.001      Pigs in BP2,3  +22.1 ± 2.2b  +30.3 ± 2.2a  +23.1 ± 2.2b  +33.2 ± 2.2a  <0.001      Pigs on ramp4  +7.2 ± 1.1b  +11.4 ± 1.1a  +6.6 ± 1.1b  +12.6 ± 1.1a  0.022      Pigs in TP5,6  –13.1 ± 2.9bc  –19.9 ± 2.9ab  –11.2 ± 2.9c  –26.7 ± 2.9a  0.003  Behavior, occurrences per loading event7      In BP2                    Balks  1.3 ± 0.5c  8.9 ± 2.3b  6.6 ± 1.6b  24.4 ± 6.2a  <0.001          Back up  0.0 ± 0.0b  0.7 ± 0.3b  0.4 ± 0.3b  5.1 ± 0.9a  <0.001          Vocalizations  1.0 ± 0.7b  1.1 ± 0.6b  1.3 ± 0.6b  11.6 ± 2.4a  0.002      On ramp8          Balks  2.7 ± 1.2b  14.4 ± 2.6a  5.6 ± 1.2b  14.9 ± 5.2a  0.004  Unloading time,9 s      First pig  20.7 ± 12.8b  28.3 ± 12.8b  35.1 ± 12.8b  78.6 ± 12.8a  0.006      Group  136.3 ± 42.1b  238.4 ± 42.1b  172.1 ± 42.1b  413.4 ± 42.1a  <0.001  Handling, occurrences per loading event7      In BP2                    Voice  7.1 ± 1.8b  26.3 ± 5.2a  11.0 ± 1.8b  43.7 ± 7.6a  0.002          Noise with paddle  21.0 ± 7.0b  107.0 ± 26.9a  36.9 ± 9.0b  105.9 ± 12.7a  0.006          Touch/slap  3.3 ± 1.6b  6.4 ± 2.0b  1.9 ± 1.0b  48.3 ± 20.0a  0.010          Push  0.1 ± 0.1b  1.1 ± 0.6b  0.4 ± 0.3b  16.1 ± 4.1a  0.045      On ramp          Voice  1.6 ± 0.7c  11.4 ± 2.3a  5.4 ± 0.8b  16.1 ± 3.0a  0.001          Noise with paddle  2.6 ± 1.1c  48.6 ± 10.6a  11.4 ± 2.2b  22.6 ± 7.2a  <0.001          Touch/slap  0.1 ± 0.1c  3.29 ± 2.8b  1.3 ± 0.6bc  11.0 ± 4.2a  0.044          Push  0.0 ± 0.0b  2.4 ± 0.8a  0.1 ± 0.1b  8.0 ± 4.1a  0.002  SHS,9,10 cm  0.3 ± 0.8c  2.9 ± 0.8b  0.6 ± 0.8c  6.2 ± 0.8a  <0.001  a–cWithin a row, means without a common superscript differ (P < 0.05). 1Difference between HRtest and HRrest. 2BP = bottom pen. 3Difference between HRBP and HRwaiting period. 4Difference between HRramp and HRBP. 5TP = top pen. 6Difference between HRrecovery period and HRramp. 7Analyzed using Kruskal-Wallis one-way analysis of variance. 8Not enough data to run the analysis on back up and vocalizations. 9Probabilities after log transformation. 10SHS = subjective handling score (cm; 0 cm = very easy; 12 cm = very difficult). View Large Pig Behavior The frequency of balking behavior (P < 0.001) was the greatest when pigs were handled in the BP toward the 26° ramp slope and lowest when handled toward the 0° ramp slope, whereas there were no differences between the 16° and 21° ramp slopes (Table 3). Pigs vocalized (P = 0.002) and backed up more (P < 0.001) when they were moved to the 26° ramp than pigs in the other treatments (Table 3). On the ramp, the number of balking events was greater (P = 0.004) when the 16° and the 26° ramps were used and did not differ (P > 0.05) between the 0° and 21° ramp slopes. Ease of Handling It took longer (P = 0.006 and P < 0.001, respectively) to unload the first pig and the group of 10 pigs when the animals were moved to the 26° ramp than to the other ramps (Table 3). The handling score, positively and strongly correlated (R = 0.633; P = 0.003) with HR of the handler, was lower (P < 0.001) when the 0° and 21° ramps were used, compared with the 16° ramp, and was found to be the greatest when pigs were moved to the 26° ramp (Table 3). Unloading pigs with the 26° ramp required more slaps and touches (P = 0.010), and more pushes (P = 0.045) than the other treatments, which did not differ between each other (Table 3). However, the number of touches and slaps tended (P = 0.077) to be greater for the 16° than 21° ramp slope. The use of noise by the handler (voice and paddle) was more frequent (P = 0.002 and P = 0.006, respectively) with the 16° and 26° ramp slopes, compared with the 0° and 21° ramp slopes (Table 3). Moving pigs on the ramp required fewer pushes (P = 0.002) when pigs were moved on the 0° and 21° ramps, compared with the 16° and 26° ramps (Table 3). The number of touches and slaps was the greatest (P = 0.044) on the 26° ramp slope, and greater with the 16° sloped ramp than on the 0° ramp slope (Table 3). On the ramp, the use of noise by the handler (voice and paddle) was the greatest (P = 0.001 and P = < 0.001, respectively) when pigs were on the 16° and 26° ramp slopes, and least when they were on the 0° ramp slope (Table 3). Experiment 3 (Initial Step at Ramp Entrance) Heart Rate The increase in the HR of the handler was the greatest (P < 0.001) when the initial step was used (Table 4) and tended (P = 0.082) to be the greatest when the 21° ramp slope was used. When pigs were moved to the ramp, the increases in pig heart rate were found to be greater (P < 0.001) in the step treatment. The same results were observed when pigs were on the ramp and in TP (P < 0.001 for both; Table 4). No differences (P > 0.05) in heart rate between the slope treatments were observed when pigs were in BP, on the ramp, or in the TP. Table 4. Effects of step (Step) to ramp on heart rate (HR), unloading time, and handling score (LS mean ± SEM) during simulated unloading   Slope  Step  P-value  Item  16°  21°  SEM  Without  With  SEM  Slope  Step  Slope × Step  HR, %      Handler1  +31.4  +36.3  1.9  +28.4b  +40.8a  1.9  0.082  <0.001  0.985      Pigs in BP2,3  +23.9  +21.1  1.1  +22.2b  +31.1a  1.1  0.171  <0.001  0.722      Pigs on ramp4  +6.1  +6.9  0.9  +4.2b  +9.2a  0.9  0.782  <0.001  0.938      Pigs in TP5,6  –16.1  –15.6  1.1  –13.6b  –17.3a  1.1  0.873  0.041  0.742  Unloading time,7 s      First pig  38.6  40.2  7.4  14.1b  35.7a  7.4  0.113  0.002  0.201      Group  207.8  152.1  19.6  107.1b  252.8a  19.6  0.104  <0.001  0.120  Handling  SHS,7,8 cm  2.7  3.2  0.8  2.1b  3.8a  0.8  0.463  0.028  0.123    Slope  Step  P-value  Item  16°  21°  SEM  Without  With  SEM  Slope  Step  Slope × Step  HR, %      Handler1  +31.4  +36.3  1.9  +28.4b  +40.8a  1.9  0.082  <0.001  0.985      Pigs in BP2,3  +23.9  +21.1  1.1  +22.2b  +31.1a  1.1  0.171  <0.001  0.722      Pigs on ramp4  +6.1  +6.9  0.9  +4.2b  +9.2a  0.9  0.782  <0.001  0.938      Pigs in TP5,6  –16.1  –15.6  1.1  –13.6b  –17.3a  1.1  0.873  0.041  0.742  Unloading time,7 s      First pig  38.6  40.2  7.4  14.1b  35.7a  7.4  0.113  0.002  0.201      Group  207.8  152.1  19.6  107.1b  252.8a  19.6  0.104  <0.001  0.120  Handling  SHS,7,8 cm  2.7  3.2  0.8  2.1b  3.8a  0.8  0.463  0.028  0.123  a,bWithin a row, means without a common superscript differ (P < 0.05). 1Difference between HRtest and HRrest. 2BP = bottom pen. 3Difference between HRBP and HRwaiting period. 4Difference between HRramp and HRBP. 5TP = top pen. 6Difference between HRrecovery period and HRramp. 7Probabilities after log transformation. 8SHS = subjective handling score (cm; 0cm = very easy; 12cm = very difficult). View Large Table 4. Effects of step (Step) to ramp on heart rate (HR), unloading time, and handling score (LS mean ± SEM) during simulated unloading   Slope  Step  P-value  Item  16°  21°  SEM  Without  With  SEM  Slope  Step  Slope × Step  HR, %      Handler1  +31.4  +36.3  1.9  +28.4b  +40.8a  1.9  0.082  <0.001  0.985      Pigs in BP2,3  +23.9  +21.1  1.1  +22.2b  +31.1a  1.1  0.171  <0.001  0.722      Pigs on ramp4  +6.1  +6.9  0.9  +4.2b  +9.2a  0.9  0.782  <0.001  0.938      Pigs in TP5,6  –16.1  –15.6  1.1  –13.6b  –17.3a  1.1  0.873  0.041  0.742  Unloading time,7 s      First pig  38.6  40.2  7.4  14.1b  35.7a  7.4  0.113  0.002  0.201      Group  207.8  152.1  19.6  107.1b  252.8a  19.6  0.104  <0.001  0.120  Handling  SHS,7,8 cm  2.7  3.2  0.8  2.1b  3.8a  0.8  0.463  0.028  0.123    Slope  Step  P-value  Item  16°  21°  SEM  Without  With  SEM  Slope  Step  Slope × Step  HR, %      Handler1  +31.4  +36.3  1.9  +28.4b  +40.8a  1.9  0.082  <0.001  0.985      Pigs in BP2,3  +23.9  +21.1  1.1  +22.2b  +31.1a  1.1  0.171  <0.001  0.722      Pigs on ramp4  +6.1  +6.9  0.9  +4.2b  +9.2a  0.9  0.782  <0.001  0.938      Pigs in TP5,6  –16.1  –15.6  1.1  –13.6b  –17.3a  1.1  0.873  0.041  0.742  Unloading time,7 s      First pig  38.6  40.2  7.4  14.1b  35.7a  7.4  0.113  0.002  0.201      Group  207.8  152.1  19.6  107.1b  252.8a  19.6  0.104  <0.001  0.120  Handling  SHS,7,8 cm  2.7  3.2  0.8  2.1b  3.8a  0.8  0.463  0.028  0.123  a,bWithin a row, means without a common superscript differ (P < 0.05). 1Difference between HRtest and HRrest. 2BP = bottom pen. 3Difference between HRBP and HRwaiting period. 4Difference between HRramp and HRBP. 5TP = top pen. 6Difference between HRrecovery period and HRramp. 7Probabilities after log transformation. 8SHS = subjective handling score (cm; 0cm = very easy; 12cm = very difficult). View Large Pig Behavior Pigs balked (P = 0.021) and vocalized (P = 0.038) more in BP when the step was used with the 16° ramp slope (Table 5). There were no differences (P > 0.05) in balking or vocalization of pigs in BP between the other treatments. The use of the initial step did not significantly (P > 0.05) affect the frequency of backup behavior in BP (Table 5). On the ramp, frequency of balking events was the greatest (P = 0.004) when the 16° ramp slope was used with a step. Table 5. Effects of step (Step) to ramp on pig behavior and ease of handling (LS mean ± SEM) during simulated unloading   Ramp configuration  Item  16°  16° Step  21°  21° Step  P-value  Behavior, occurrences per unloading event1      In BP2,          Balks  2.6 ± 1.5b  15.7 ± 3.2a  3.1 ± 0.6b  5.3 ± 1.5b  0.021          Back up  0.4 ± 0.2  1.4 ± 0.6  0.7 ± 0.4  2.7 ± 1.3  0.641          Vocalizations  0.6 ± 0.4b  6.1 ± 1.7a  0.9 ± 0.5b  2.0 ± 1.1b  0.038      On ramp3          Balks  3.1 ± 1.2b  10.1 ± 1.2a  2.6 ± 1.2b  3.3 ± 1.0b  0.004  Handling, occurrences per unloading event1      In BP2          Voice  9.4 ± 1.4  19.9 ± 5.1  11.9 ± 1.9  13.4 ± 3.2  0.175          Noise with paddle  18.0 ± 6.1b  64.0 ± 5.4a  21.3 ± 4.4b  35.3 ± 9.5b  0.007          Touch/slap  7.1 ± 1.8c  57.3 ± 7.4a  21.6 ± 6.3b  32.0 ± 5.9b  0.005          Push  1.4 ± 1.0b  18.3 ± 3.5a  3.9 ± 1.3b  18.1 ± 4.5a  0.004      On ramp4          Noise with paddle  1.9 ± 0.7  4.0 ± 3.4  5.0 ± 2.5  0.6 ± 0.3  0.427          Touch/slap  0.6 ± 0.4  4.1 ± 1.7  5.6 ± 4.8  2.0 ± 0.5  0.096          Push  0.0 ± 0.0b  4.4 ± 1.6a  5.5 ± 3.7a  0.4 ± 0.2b  0.024    Ramp configuration  Item  16°  16° Step  21°  21° Step  P-value  Behavior, occurrences per unloading event1      In BP2,          Balks  2.6 ± 1.5b  15.7 ± 3.2a  3.1 ± 0.6b  5.3 ± 1.5b  0.021          Back up  0.4 ± 0.2  1.4 ± 0.6  0.7 ± 0.4  2.7 ± 1.3  0.641          Vocalizations  0.6 ± 0.4b  6.1 ± 1.7a  0.9 ± 0.5b  2.0 ± 1.1b  0.038      On ramp3          Balks  3.1 ± 1.2b  10.1 ± 1.2a  2.6 ± 1.2b  3.3 ± 1.0b  0.004  Handling, occurrences per unloading event1      In BP2          Voice  9.4 ± 1.4  19.9 ± 5.1  11.9 ± 1.9  13.4 ± 3.2  0.175          Noise with paddle  18.0 ± 6.1b  64.0 ± 5.4a  21.3 ± 4.4b  35.3 ± 9.5b  0.007          Touch/slap  7.1 ± 1.8c  57.3 ± 7.4a  21.6 ± 6.3b  32.0 ± 5.9b  0.005          Push  1.4 ± 1.0b  18.3 ± 3.5a  3.9 ± 1.3b  18.1 ± 4.5a  0.004      On ramp4          Noise with paddle  1.9 ± 0.7  4.0 ± 3.4  5.0 ± 2.5  0.6 ± 0.3  0.427          Touch/slap  0.6 ± 0.4  4.1 ± 1.7  5.6 ± 4.8  2.0 ± 0.5  0.096          Push  0.0 ± 0.0b  4.4 ± 1.6a  5.5 ± 3.7a  0.4 ± 0.2b  0.024  a–cWithin a row, means without a common superscript differ (P < 0.05). 1Analyzed using Kruskal-Wallis one-way analysis of variance. 2BP = bottom pen. 3Not enough data to run the analysis on back up and vocalizations. 4Not enough data to run the analysis on voice. View Large Table 5. Effects of step (Step) to ramp on pig behavior and ease of handling (LS mean ± SEM) during simulated unloading   Ramp configuration  Item  16°  16° Step  21°  21° Step  P-value  Behavior, occurrences per unloading event1      In BP2,          Balks  2.6 ± 1.5b  15.7 ± 3.2a  3.1 ± 0.6b  5.3 ± 1.5b  0.021          Back up  0.4 ± 0.2  1.4 ± 0.6  0.7 ± 0.4  2.7 ± 1.3  0.641          Vocalizations  0.6 ± 0.4b  6.1 ± 1.7a  0.9 ± 0.5b  2.0 ± 1.1b  0.038      On ramp3          Balks  3.1 ± 1.2b  10.1 ± 1.2a  2.6 ± 1.2b  3.3 ± 1.0b  0.004  Handling, occurrences per unloading event1      In BP2          Voice  9.4 ± 1.4  19.9 ± 5.1  11.9 ± 1.9  13.4 ± 3.2  0.175          Noise with paddle  18.0 ± 6.1b  64.0 ± 5.4a  21.3 ± 4.4b  35.3 ± 9.5b  0.007          Touch/slap  7.1 ± 1.8c  57.3 ± 7.4a  21.6 ± 6.3b  32.0 ± 5.9b  0.005          Push  1.4 ± 1.0b  18.3 ± 3.5a  3.9 ± 1.3b  18.1 ± 4.5a  0.004      On ramp4          Noise with paddle  1.9 ± 0.7  4.0 ± 3.4  5.0 ± 2.5  0.6 ± 0.3  0.427          Touch/slap  0.6 ± 0.4  4.1 ± 1.7  5.6 ± 4.8  2.0 ± 0.5  0.096          Push  0.0 ± 0.0b  4.4 ± 1.6a  5.5 ± 3.7a  0.4 ± 0.2b  0.024    Ramp configuration  Item  16°  16° Step  21°  21° Step  P-value  Behavior, occurrences per unloading event1      In BP2,          Balks  2.6 ± 1.5b  15.7 ± 3.2a  3.1 ± 0.6b  5.3 ± 1.5b  0.021          Back up  0.4 ± 0.2  1.4 ± 0.6  0.7 ± 0.4  2.7 ± 1.3  0.641          Vocalizations  0.6 ± 0.4b  6.1 ± 1.7a  0.9 ± 0.5b  2.0 ± 1.1b  0.038      On ramp3          Balks  3.1 ± 1.2b  10.1 ± 1.2a  2.6 ± 1.2b  3.3 ± 1.0b  0.004  Handling, occurrences per unloading event1      In BP2          Voice  9.4 ± 1.4  19.9 ± 5.1  11.9 ± 1.9  13.4 ± 3.2  0.175          Noise with paddle  18.0 ± 6.1b  64.0 ± 5.4a  21.3 ± 4.4b  35.3 ± 9.5b  0.007          Touch/slap  7.1 ± 1.8c  57.3 ± 7.4a  21.6 ± 6.3b  32.0 ± 5.9b  0.005          Push  1.4 ± 1.0b  18.3 ± 3.5a  3.9 ± 1.3b  18.1 ± 4.5a  0.004      On ramp4          Noise with paddle  1.9 ± 0.7  4.0 ± 3.4  5.0 ± 2.5  0.6 ± 0.3  0.427          Touch/slap  0.6 ± 0.4  4.1 ± 1.7  5.6 ± 4.8  2.0 ± 0.5  0.096          Push  0.0 ± 0.0b  4.4 ± 1.6a  5.5 ± 3.7a  0.4 ± 0.2b  0.024  a–cWithin a row, means without a common superscript differ (P < 0.05). 1Analyzed using Kruskal-Wallis one-way analysis of variance. 2BP = bottom pen. 3Not enough data to run the analysis on back up and vocalizations. 4Not enough data to run the analysis on voice. View Large Ease of Handling It took more time (P = 0.002 and P < 0.001, respectively) to unload the first pig or the group when the initial step was used (Table 4). The handling score, positively and moderately correlated (R = 0.378; P = 0.047) with the HR of the handler was greater (P = 0.028) when the 16° ramp slope was used compared with the 21° ramp slope, whereas the use of the step had no effect (P > 0.05) on this variable (Table 4).In BP the use of voice did not differ significantly (P > 0.05) among the 4 treatments, but a greater number of slaps and touches (P = 0.005), and more frequent use of the paddle to make noise (P = 0.007) was observed when a step was used with the 16° ramp slope than with the 21° ramp slope (Table 5). The frequency of pushes was greater (P = 0.004) when a step was used than when it was not, for both ramp slopes (Table 5). On the ramp, use of the paddle to make noise and frequency of touches and slaps did not differ between treatments, although there was a trend toward more touches and slaps being used on the 16° sloped ramp with an initial step than without (P = 0.096). The number of pushes on the ramp was the lowest (P = 0.024) when the 16° ramp slope with no step or when the 21° ramp slope with a step were used. Frequency of pushes was similar for pigs on the 16° ramp with step and the 21° sloped ramp without a step (Table 5). DISCUSSION The results show that using a 90° angle of entrance to the ramp has detrimental effects on ease of handling, HR of the pig, and behavior of the pig. Because pigs have a tendency to circle around the handler (Grandin, 1997b), they tended to walk along the wall on 1 side of the pen and then got stuck in this corner, probably because they viewed the 90° turn as a dead end (Carpenter et al., 1993; Chevillon, 1998). Thus, more handling was required to get them to move toward the ramp. This observation is in line with the recommendations made by Grandin (1990), suggesting that handling facilities should not have any 90° corners to ease animal movement before slaughter. Our results are also in agreement with those of Warriss et al. (1992), who found a greater moving time in a race with a 90° angle than with a 45° bend. Reducing the angle of entrance with the use of boards allowed the handler to direct pigs to the ramp without any possibility for pigs to hide in a corner. The 0° and 30° angles of entrance appeared to improve the ease of unloading, whereas the 60° angle had an intermediate effect. The 30° angle seemed to be preferable, because pigs moved at this angle balked less frequently and required less manipulation by the handler. This pen configuration is quite similar to the one recommended by Grandin (1982) for crowd pen designs using a single offset step to prevent jamming at the entrance of a single file ramp. In the present study, the use of a 30° angle of entrance may have improved movement flow by creating a smoother pathway along the wall. Results of the second experiment demonstrate that a flat ramp improved the ease of handling, based on the lower HR of the handler and lower number of vocal and paddle interventions required by the handler to move the pigs on the ramp. However, the flat ramp did not differ from the 21° ramp in many of the variables reflecting ease of handling, which may be explained by the difference in configuration between the ramps. Indeed, due to the ramp area configuration associated with the 0° ramp (ramp on the ground with a 91-cm wall on each side), pigs unloaded with this ramp had to go through a narrow corridor to reach the other pen, which could have been perceived as psychologically stressful as a 21° sloped ramp. It is not clear why the 16° slope created more handling difficulties than the 21° slope, as shown by variables such as pig HR, balking on the ramp, voice, and noise with paddle. In the present study, slope modifications were made by changing the length of the ramps (2.54 and 1.95 m for the 16° and 21° ramps, respectively), which might have influenced how the animal perceived the ramp. Thus, animals may have perceived the 16° ramp as more psychologically and physically challenging than the 21° ramp, because it represented a longer walk to reach the other side. Because space on a trailer is usually limited, a folding ramp extension has been previously suggested as a potential solution to the detrimental effect of steep ramp slopes associated with short ramps (Van Putten and Elshoff, 1978; Grandin, 1979). However, the present results suggest that ramp length may have a negative effect on ease of unloading. The results of this experiment clearly show that the use of the steepest 26° ramp slope had the most detrimental effect on behavior and handling of the pig. This is consistent with studies demonstrating that a ramp slope >20° leads to a significant increase in unloading time (Warriss et al., 1991) and more frequent balking behavior (Phillips et al., 1988). The 26° ramp may have been perceived as more psychologically and physically challenging by the pigs, compared with the other ramp slopes. Reluctance of the pig to move resulted in more handler vocalizations and interventions. The increase in HR of the pig was also greater with the 26° ramp. However, this increase was not different from the increase associated with the use of the 16° ramp, again, probably because the 16° ramp was longer than the 26° ramp (2.54 and 1.60 m for the 16° and 26° ramps, respectively). This would explain why the present results are not consistent with the findings of Van Putten and Elshoff (1978) and Mayes and Jesse (1980), who showed a direct positive correlation between HR during loading and ramp slope. The use of an initial step was tested in Exp. 3 because it may be used to either reduce the ramp slope or length of the ramp. Phillips et al. (1988) showed that young pigs used a staircase composed of small steps at least as readily as a ramp of similar slope, whereas staircase designs with fewer, larger steps were not preferred. However, the results of the present study show that a step associated with a ramp made the work more challenging for the handler, as indicated by his greatest HR when pigs were moved to the ramps with a step, reflecting a greater physical effort or stress. In addition, unloading was more difficult to initiate when the initial step was used, which may explain the greater time to unload pigs with the ramps combined with the step. The presence of the step also made the unloading more physically demanding for the animal as shown by the greater increase in HR of the pigs on the ramp. In line with our results, handling problems due to refusal or hesitation of the pigs to leave the truck voluntarily have been related to height differences between the truck and unloading ramp when step height was >15 cm (SCAHAW, 2002). The greater difficulty of handling and reluctance to move of pigs moved toward the 16° ramp with a step suggest that pigs perceived this ramp as more challenging. As suggested in Exp. 2, the length of the ramp may have had an effect on how a pig perceived the ramp. Thus, there may have been combined effects of the use of the step and the ramp slope. However, when comparing the ramps not associated with an initial step, the results obtained in Exp. 2 and 3 are not in line, even though similar conditions (handler, tools and simulated compartments) were applied. In contrast to Exp. 2, there were no differences between pigs in the 16° and 21° ramp slope treatments in experiment 3. Compared to pigs in Exp. 2, pigs moved to the 16° ramp in Exp. 3 seemed to balk less and require less handling. The reason for this discrepancy is not known. Human factors, such as the handler becoming more familiar with the experimental set-up and more efficient at moving animals, cannot be completely ruled out. On commercial trailers, ramp slopes in PB can be as steep as 41° (Weschenfelder et al., 2012) and the presence of 1 or 2 (at the top and bottom of the ramp) steps is quite common (Goumon, personal observations). Our study suggests that ramp slope should not be greater than 21° and that a step at the bottom of the ramp is not recommended. For ramp slopes steeper than 21°, the use of a ramp extension may not be the most appropriate modification to facilitate handling because, as suggested by the results of the present study, the beneficial effect of a lower ramp angle is possibly counteracted by a longer ramp length. Elevating the “pot” floor could be suggested to decrease the ramp slope. However, this modification means an elevation of the whole truck, which may not be possible for safety reasons. Our results also show that angle of entrance should not be >30°. This can be easily implemented by setting up a board, before loading, on 1 side of the entrance. However, it has to be noted that this procedure leads to a reduction of the surface available in the compartment equivalent to 2 market-weight pigs, according to our estimates. Conclusions The results demonstrate that ramp configuration has an effect on the efficiency of unloading pigs and their behavior. Animals appear more reluctant to move when a steep ramp, an initial step associated with a moderate slope, or a wide angle of entrance are used. The current configuration of the “pot” compartment in PB trailers is not ideal and does not match these recommendations. Although unloading may be a physically demanding exercise, this study highlights that the way pigs first perceive the ramp as they are moved to it is the main contributing factor to handling difficulty. Animals refusing to move up a ramp can lead to unnecessary rough handling. Thus, making a few ramp design changes could improve efficiency of handling and welfare of pigs and handler. LITERATURE CITED Barton-Gade P. Christensen L. Baltzer M. Petersen J. V. 2007. Causes of preslaughter mortality in Danish slaughter pigs with special emphasis on transport. Anim. Welf.  16: 459– 470. Bradshaw R. H. Parrott R. F. Forsling M. L. Goode J. A. Lloyd D. M. Rodway R. G. Broom D. 1996. Stress and travel sickness in pigs: Effects of road transport on plasma concentrations of cortisol, beta-endorphin and lysine vasopressin. Anim. Sci.  63: 507– 516. Google Scholar CrossRef Search ADS   Brown J. A. Dewey C. Delange C. F. M. Mandell I. B. Purslow P. P. Robinson J. A. Squires E. J. Widowski T. M. 2009. Reliability of temperament tests on finishing pigs in group housing and comparison to social tests. Appl. Anim. Behav. Sci.  118: 28– 35. Google Scholar CrossRef Search ADS   Brown S. N. Knowles T. G. Wilkins L. J. Chadd S. A. Warriss P. D. 2005. The response of pigs to being loaded or unloaded onto commercial animal transporters using three systems. Vet. J.  170: 91– 100. Canadian Council on Animal Care 2009. Guidelines on: The care and use of farm animals in research, teaching and testing. Canadian Council on Animal Care, Ottawa, ON. Carpenter J. D. Hoehne J. A. Mayes H. F. 1993. Corral systems for handling and sorting hogs. Agric. Publ. G01165.  http://muextension.missouri.edu/explore/agguides/agengin/g01165.htm. (Accessed 22 October 2012.) Chevillon P. 1998. Taux de mortalité lors du transport et du bien-être du porc. Techni-porc.  21: 13– 18. Grandin T. 1979. Designing meat packing plant handling facilities for cattle and hogs. Trans. ASAE  22: 912– 917. Google Scholar CrossRef Search ADS   Grandin T. 1982. Pig behavior studies applied to slaughter-plant design. Appl. Anim. Ethol.  9: 141– 151. Google Scholar CrossRef Search ADS   Grandin T. 1990. Design of loading facilities and holding pens. Appl. Anim. Behav. Sci.  28: 187– 201. Google Scholar CrossRef Search ADS   Grandin T. 1997a. Assessment of stress during handling and transport. J. Anim. Sci.  75: 245– 257. Google Scholar CrossRef Search ADS   Grandin T. 1997b. The design and construction of facilities for handling cattle. Livest. Prod. Sci.  49: 103– l19. Google Scholar CrossRef Search ADS   Lambooij E. Van Putten G. 2000. Transport of pigs. 2nd ed. In: Grandin T. editor, Livestock handling and transport.  CAB International, Wallingford, Oxon, UK. p. 228– 244. Mayes H. F. Jesse G. W. 1980. Heart rate data of feeder pigs. Tech. Pap. 80–4023. Am. Soc. Agric. Eng., St. Joseph, MI. p. 1– 8. Phillips P. A. Thompson B. K. Fraser D. 1988. Preference tests of ramp designs for young pigs. Can. J. Anim. Sci.  68: 41– 48. Google Scholar CrossRef Search ADS   Riches H. L. Guise H. J. Penny R. H. C. Jones T. Cuthbertson A. 1996. A national survey of transport conditions for pigs. Pig J.  38: 8– 18. Ritter M. J. Ellis M. Bowman R. Brinkmann J. Curtis S. E. DeDecker J. M. Mendoza O. Murphy C. M. Orellana D. G. Peterson B. A. Rojo A. Schlipf J. M. Wolter B. F. 2008. Effects of season and distance moved during loading on transport losses of market-weight pigs in two commercially available types of trailer. J. Anim. Sci.  86: 3137– 3145. Google Scholar CrossRef Search ADS PubMed  SCAHAW. 2002. Report of the Scientific Committee on Animal Health and Animal Welfare adopted on 11 March 2002: The welfare of animals during transport (details for horses, pigs, sheep and cattle). European Commission, Health and Consumer Protection, Brussels, Belgium. p. 130. Schwartzkopf-Genswein K. S. Faucitano L. Dadgar S. Shand P. Gonzàlez L. A. Crowe T. G. 2012. Road transport of cattle, swine and poultry in North America and its impact on animal welfare, carcass and meat quality: A review. Meat Sci.  92: 227– 243. Google Scholar CrossRef Search ADS PubMed  Torrey S. Bergeron R. Widowski T. Lewis N. Crowe T. Correa J. A. Brown J. Gonyou H. W. Faucitano L. 2013. Transportation of market-weight pigs 1. Effect of season, truck type, and location within truck on behavior with a 2-h transport. J. Anim. Sci.  91: 2863– 2871. Google Scholar CrossRef Search ADS PubMed  Van Putten G. Elshoff G. 1978. Observations on the effect of transport on the well being and lean quality of slaughter pigs. Animal Reg. Stud.  1: 247– 271. Warriss P. D. 1998. The welfare of slaughter pigs during transport. Anim. Welf.  7: 365– 381. Warriss P. D. Bevis E. A. Edwards J. E. Brown S. N. Knowles T. G. 1991. Effect of the angle of slope on the ease with which pigs negotiate loading ramps. Vet. Rec.  128: 419– 421. Google Scholar CrossRef Search ADS PubMed  Warriss P. D. Brown S. N. Knowles T. G. Edwards J. E. 1992. Influence of width and bends on the ease of movement of pigs along races. Vet. Rec.  130: 202– 204. Google Scholar CrossRef Search ADS PubMed  Weschenfelder A. V. Torrey S. Devillers N. Crowe T. Bassols A. Saco Y. Piñeiro M. Saucier L. Faucitano L. 2012. Effects of trailer design on animal welfare parameters and carcass and meat quality of three Pietrain crosses being transported over a long distance. J. Anim. Sci.  90: 3220– 3231. Google Scholar CrossRef Search ADS PubMed  American Society of Animal Science
TI - Effect of ramp configuration on easiness of handling, heart rate, and behavior of near-market weight pigs at unloading
JF - Journal of Animal Science
DO - 10.2527/jas.2012-6083
DA - 2013-08-01
UR - https://www.deepdyve.com/lp/oxford-university-press/effect-of-ramp-configuration-on-easiness-of-handling-heart-rate-and-Bx2NEAPCH0
SP - 3889
EP - 3898
VL - 91
IS - 8
DP - DeepDyve
ER -