M. J. Ritter

Effect of floor space during transport of market-weight pigs on the incidence of transport losses at the packing plant and the relationships between transport conditions and losses

Data on 74 trailer loads of finishing pigs (mean BW = 129.0, SEM = 0.63 kg) from wean-to-finish buildings on 2 farms within 1 production system were collected to investigate the effect of amount of floor space on the trailer (0.39 or 0.48 m2/pig) during transport on the incidence of losses (dead and nonambulatory pigs) at the packing plant and to study the relationships between transport conditions and losses. Pigs were loaded using standard commercial procedures for pig handling and transportation. Two designs of flat-deck trailers with 2 decks were used. Floor space treatments were compared in 2 similarly sized compartments on each deck of each trailer type. Differences in floor space were created by varying the number of pigs in each compartment. The incidence of nonambulatory pigs at the farm during loading and at the plant after unloading, average load weight, load number within each day, event times, and temperature and relative humidity in the trailer from loading to unloading were recorded. Of the 12,511 pigs transported, 0.26% were non-ambulatory at the farm, 0.23% were dead on arrival, and 0.85% were nonambulatory at the plant. Increasing transport floor space from 0.39 to 0.48 m2/pig reduced the percentage of total nonambulatory pigs (0.62 vs. 0.27 +/- 0.13%, respectively; P < 0.05), nonambulatory, noninjured pigs (0.52 vs. 0.15 +/- 0.11%, respectively; P < 0.01), and total losses (dead and nonambulatory pigs) at the plant (0.88 vs. 0.36 +/- 0.16%, respectively; P < 0.05) and tended to reduce dead pigs (0.27 vs. 0.08 +/- 0.08%, respectively; P = 0.06). However, transport floor space did not affect the percentage of nonambulatory, injured pigs at the plant. Nonambulatory pigs at the farm were positively correlated with relative humidity during loading and load number within the day (r = 0.46 and 0.25, respectively; P < 0.05). The percentage of total losses at the plant was positively correlated to waiting time at the plant, unloading time, and total time from loading to unloading (r = 0.24, 0.51, and 0.36, respectively; P < 0.05). Average temperature during loading, waiting at the farm, transport, waiting at the plant, unloading, and average pig weight on the trailer were not correlated to losses. These results suggest that floor space per pig on the trailer and transport conditions can affect transport losses.

Review:Transport Losses in Market Weight Pigs: I. A Review of Definitions, Incidence, and Economic Impact

ABSTRACT Transport losses (dead and nonambulatory pigs) present animal welfare, legal, and economic challenges to the US swine industry. The objectives of this review are to explore 1) the historical perspective of transport losses; 2) the incidence and economic implications of transport losses; and 3) the symptoms and metabolic characteristics of fatigued pigs. In 1933 and 1934, the incidence of dead and nonambulatory pigs was reported to be 0.08 and 0.16%, respectively. More recently, 23 commercial field trials (n = 6,660,569 pigs) were summarized and the frequency of dead pigs, nonambulatory pigs, and total transport losses at the processing plant were 0.25, 0.44, and 0.69% respectively. In 2006, total economic losses associated with these transport losses were estimated to cost the US pork industry approximately

Effects of multiple concurrent stressors on rectal temperature, blood acid-base status, and longissimus muscle glycolytic potential in market-weight pigs.

46 million. Furthermore, 0.37 and 0.05% of the nonambulatory pigs were classified as either fatigued (nonambulatory, noninjured) or injured, respectively, in 18 of these trials (n = 4,966,419 pigs). Fatigued pigs display signs of acute stress (open-mouth breathing, skin discoloration, muscle tremors) and are in a metabolic state of acidosis, characterized by low blood pH and high blood lactate concentrations; however, the majority of fatigued pigs will recover with rest. Transport losses are a multifactorial problem consisting of people, pig, facility design, management, transportation, processing plant, and environmental factors, and, because of these multiple factors, continued research efforts are needed to understand how each of the factors and the relationships among factors affect the well-being of the pig during the marketing process.

Effects of season and distance moved during loading on transport losses of market-weight pigs in two commercially available types of trailer

Sixty-four market-weight (130.0 +/- 0.65 kg) barrows (n = 16) and gilts (n = 48) were used in a split-plot design with a 2 x 2 x 2 factorial arrangement of treatments: 1) handling intensity (gentle vs. aggressive), 2) transport floor space (0.39 vs. 0.49 m(2)/pig), and 3) distance moved during handling (25 vs. 125 m) to determine the effects of multiple concurrent stressors on metabolic responses. For the handling intensity treatment, pigs were moved individually approximately 50 m through a handling course with either 0 (gentle) or 8 (aggressive) shocks from an electric goad. Pigs were loaded onto a trailer and transported for approximately 1 h at floor spaces of either 0.39 or 0.49 m(2)/pig. After transport, pigs were unloaded, and the distance moved treatment was applied; pigs were moved 25 or 125 m through a handling course using livestock paddles. Rectal temperature was measured, and blood samples (to measure blood acid-base status) were collected 2 h before the handling intensity treatment was applied and immediately after the distance moved treatment was applied. A LM sample to measure glycolytic potential was collected after the distance moved treatments on a subset of 32 pigs. There were handling intensity x distance moved interactions (P < 0.05) for several blood acid-base measurements. In general, there was no effect of distance moved on these traits when pigs were previously handled gently. However, when pigs were previously handled aggressively, pigs moved 125 compared with 25 m had greater (P < 0.05) blood lactate and less (P < 0.05) blood pH, bicarbonate, and base-excess. Pigs transported at 0.39 compared with 0.49 m(2)/pig had a greater (P < 0.01) increase in creatine kinase values; however, transport floor space did not affect any other measurements. Data were analyzed by the number of stressors (the aggressive handling, restricted transport floor space, and 125-m distance moved treatments) experienced by each pig (0, 1, 2, or 3). As the number of stressors experienced by the pig increased, rectal temperature, blood lactate, and LM lactate increased linearly (P <or= 0.01), and blood pH, bicarbonate, and base-excess decreased linearly (P < 0.01). These data suggest that the stressors evaluated had additive effects on several indicators of metabolic stress responses in finishing pigs.

2011 and 2012 Early Careers Achievement Awards: farm and pig factors affecting welfare during the marketing process.

This study evaluated effects of trailer design and season on physical indicators of stress during loading and unloading and transport losses (dead and nonambulatory pigs) in market-weight pigs (BW = 129.6 +/- 0.40 kg). A total of 109 trailer loads of pigs (n = 17,256 pigs) from 1 farm were used in a randomized complete block design with a 2 x 4 factorial arrangement of treatments: 1) trailer design (potbelly vs. straight-deck) and 2) season (spring vs. summer vs. fall vs. winter). A subset of loads (n = 42) was used to examine effect of distance pigs were moved during loading [short (<24 m) vs. long (47 to 67 m)] on physical indicators of stress and transport losses. This study was conducted on 7 d per season at 1 farm with 4 loads (2 on potbelly and 2 on straight-deck trailers) being transported each day to 1 commercial packing plant. Pigs from different farm groups were mixed on the trailer and provided with 0.45 m(2)/pig floor space during an approximately 4-h journey to the plant. The percentage of pigs exhibiting open-mouth breathing, skin discoloration, and muscle tremors was recorded during loading and unloading. Additionally, dead pigs on arrival at the plant and nonambulatory pigs at the farm and at the plant were recorded. Effects of trailer design on open-mouth breathing and skin discoloration during unloading were dependent on season (trailer design x season interaction; P < 0.05). Pigs unloaded from potbelly trailers had a greater (P < or = 0.05) incidence of open-mouth breathing in the spring and summer and a greater (P < 0.05) incidence of skin discoloration in the spring, summer, and winter than pigs unloaded from straight-deck trailers. The incidence of total nonambulatory pigs at the plant was greater (P < 0.05) in the winter than in the spring and summer. The long compared with short distance moved treatment resulted in a greater (P = 0.001) incidence of open-mouth breathing and skin discoloration during loading and tended (P = 0.06) to increase the incidence of nonambulatory pigs at the farm. However, there was no effect of trailer design, season, or loading distance on total losses at the plant. In summary, physical indicators of stress (open-mouth breathing and skin discoloration) were increased with the long distance moved during loading treatment and were greater during unloading for potbelly than straight-deck trailers; however, trailer design, season, and loading distance had minimal effects on total transport losses.

Ractopamine (Paylean) response in heavy-weight finishing pigs.

The objective of this paper is to review the scientific literature to identify on-farm factors that contribute to market weight pig transportation losses. Transportation of market weight pigs is an essential element to the multisite pork production model used in the United States. In 2011 alone, approximately 111 million market weight pigs were transported from the finishing site to the abattoir. For pigs, the marketing process can present a combination of potentially novel, physical, and/or unfamiliar experiences that can be stressful. If the pig cannot cope with these sequential and additive stressors, then an increased rate of transportation losses could occur with a detrimental effect on pork carcass value. Current yearly estimates for transport losses are 1 million pigs (1%). A variety of market weight pig and farm factors have been reported to detrimentally affect transportation losses. By understanding how pigs interact with their environment during marketing, researchers, producers, and personnel at the abattoir may begin to identify, prioritize, and attempt to minimize or eliminate these stressors. This process will ultimately decrease transportation losses, improve pork quality, and increase profitability.

Effect of feeding ractopamine hydrochloride on growth performance and responses to handling and transport in heavy-weight pigs

The objective of this study was to investigate the effects of feeding diets with 10 ppm of ractopamine hydrochloride (RAC; Paylean 9G, Elanco Animal Health, Greenfield, IN) to heavy-weight pigs (final BW of 147 kg). Few studies have addressed the effects of RAC on performance and carcass traits at the finishing BW presented in this study. This study was carried out as a randomized complete block design with a 2 × 2 factorial arrangement of treatments, 1) sex (barrow or gilt) and 2) RAC inclusion (0 or 10 ppm), with a total of 128 pigs. Pigs were randomly assigned to pens of 4 and beginning BW was approximately 115 kg. After 28 d on test, pigs were slaughtered and a subset of pigs, totaling 64 pigs (2 pigs/pen), were selected for carcass characteristics and meat quality analysis. There were no sex × RAC interactions (P > 0.10). Final farm BW was increased (P = 0.003) by 3.3 kg, overall ADG was increased (P = 0.009) by 11.0%, and overall G:F was increased (P < 0.001) by 12.9% with RAC. The HCW was increased (P < 0.001) by 3.9 kg with RAC, and dressing percentage was increased (P = 0.001) to 76.04% from 75.06%. In the subset selected for carcass characteristics (n = 64), there was a trend of increasing (P = 0.08) lean cut yield. Ultimate pH was increased (P < 0.001) by 0.08 units, and drip loss was decreased (P = 0.011) to 4.31% from 5.59% with RAC. Feeding diets with 10 ppm RAC to pigs with ending BW of approximately 147 kg proved efficacious in improving BW, ADG, G:F, HCW, and dressing percentage without adversely affecting meat quality traits.

Effects of Presorting on Stress Responses at Loading and Unloading and the Impact on Transport Losses from Market-Weight Pigs1

The impact of feeding ractopamine hydrochloride (RAC) on growth performance and responses to handling and transport in heavy BW pigs was evaluated in a study performed as a split-plot design with a 3 × 3 factorial arrangement of treatments: 1) RAC level (0 vs. 5 vs. 7.5 mg/kg of feed) and 2) handling intensity (HI; gentle vs. moderate vs. aggressive); RAC level was the main plot and HI was the subplot. A total of 288 pigs housed in groups of 8 were used to evaluate growth performance over a 28-d RAC feeding period (98.5 ± 4.58 to 131.5 ± 7.45 kg BW). On d 29 of the study, the HI treatment was applied to 216 pigs (6/pen; 2/pen on each HI). This was followed by transportation for 1 h on a livestock trailer at the end of which pigs were subjected to a final handling procedure. Blood samples (to measure acid-base, cortisol, and catecholamine levels) were collected and rectal temperature was measured 2 h before the HI treatment (baseline) and after the final handling procedure (final). Feeding RAC (5 and 7.5 mg/kg) improved ( < 0.01) ADG (9.9 and 9.0% for 5 and 7.5 mg/kg RAC, respectively) and G:F (8.8 and 11.8%, respectively) compared to controls, with no differences ( > 0.05) between the 2 RAC levels. Increasing the intensity of handling decreased ( < 0.001) final blood pH, bicarbonate, and base excess and increased ( < 0.001) final blood lactate and plasma cortisol and norepinephrine levels. Aggressive compared to gentle handling increased ( < 0.05) the incidence of pigs exhibiting open-mouth breathing and skin discoloration after the final handling procedure but had no effect ( > 0.05) on the incidence on nonambulatory, noninjured pigs. There was no effect ( > 0.05) of feeding RAC on final rectal temperature or blood acid-base measurements. Feeding 7.5, but not 5, compared to 0 mg/kg RAC increased ( < 0.05) final plasma epinephrine levels and the incidence of nonambulatory, noninjured pigs. This study confirms the improved growth performance of pigs fed RAC and the negative effects of aggressive handling on physical, metabolic, and physiological responses of pigs. It also suggests that pigs fed 5 compared to 0 mg/kg RAC showed similar responses to transport and handling. However, pigs fed 7.5 mg/kg of RAC had a greater incidence of nonambulatory, noninjured pigs when subjected to the handling/transport model and this warrants further investigation.

Impact of ractopamine hydrochloride on growth performance, carcass and pork quality characteristics, and responses to handling and transport in finishing pigs

The objective of this study was to determine the effects of presorting before loading on stress responses and transport losses at the slaughter facility in the market-weight pig. A total of 5,802 pigs (n = 33 loads) were used in a randomized complete block design with 2 treatments. The presorted (PRE) and not presorted (NON) treatments each had 292 pigs/pen (0.65 m2/pig). For the PRE treatment, internal swing gates were used to presort pigs manually 18 h before loading, whereas pigs in the NON treatment were sorted from pen mates at the time of marketing. Treatments were assigned to trailer decks in an alternating manner. Data were analyzed using generalized linear mixed model methodology, and loading time was analyzed using mixed model procedures. Loading time differed (P 0.05) different. There were no (P > 0.05) differences between treatments for total losses at the slaughter facility. Two pigs in the PRE treatment and zero pigs in the NON treatment were classified as dead on arrival. In conclusion, presorting market-weight pigs reduced loading time and some stress responses on farm; however, no treatment differences were observed for stress responses or transport losses at the slaughter facility.

Effects of grow-finish group size on stress responses at loading and unloading and the effect on transport losses from market-weight pigs1

The effect of feeding ractopamine hydrochloride (RAC) on growth performance, carcass and pork quality, and blood acid-base and catecholamine responses to handling and transport in finishing pigs was evaluated using a randomized complete block design to compare 2 RAC levels (0 vs. 10 mg/kg). Crossbred pigs ( = 144) were housed in single-sex pens (barrow or gilt) of 3 with 24 pens/RAC level. The study was carried out for a 28-d period from 104.0 ± 5.99 to 136.7 ± 6.44 kg BW. At the end of the growth study, pigs were subjected to handling and transport procedures that involved an initial aggressive handling procedure (pigs moved 50 m with 8 shocks from an electric prod) followed by a 30-min transport on a standard livestock trailer at a floor space of 0.46 m/pig followed by a final gentle handling procedure (pigs moved 100 m using sort boards and slap paddles). A blood sample was taken and rectal temperature was measured 2 h before (baseline) and immediately after the final handling procedure (final). Barrows ( = 72) were harvested and carcass and pork quality were measured. Feeding RAC increased ( ≤ 0.05) ADG (19.6%), ADFI (4.2%), and G:F (14.8%). The increase in plasma epinephrine levels from baseline to final was greater ( ≤ 0.05) for pigs fed RAC; there was a trend ( ≤ 0.10) for pigs fed RAC to have greater final blood lactate and to show a greater change from baseline to final in blood bicarbonate, partial pressure of and total carbon dioxide, and oxygen saturation levels. However, there were no differences between treatments for changes from baseline to final in rectal temperature, blood pH and lactate, and plasma norepinephrine levels. The incidence of physical indicators of stress and of nonambulatory, noninjured pigs during the handling and transport procedures was similar for the 0 and 10 mg/kg RAC levels. Final farm BW was 4.1 kg heavier, carcass yield was 1.4 percentage units greater, and LM area was 5.18 cm greater for pigs fed RAC compared to the control ( ≤ 0.05). Minolta a* and b* values were lower ( ≤ 0.05) and ultimate pH (0.05 units) and Warner-Bratzler shear force (0.43 kg) were greater ( ≤ 0.05) for pigs fed 10 compared to 0 mg/kg RAC. These results confirm the substantial improvement from feeding 10 mg/kg RAC in growth performance and carcass yield and suggest relatively limited effects on pork quality and on responses to the handling and transport procedures used in this study.