In the U.S., 113 million pigs are transported annually to market, primarily by road in a tractor trailer. The conditions under which pigs are handled and transported can have a direct impact on their well-being, which may result in increased transport losses (the sum of dead on arrival and non-ambulatory (sum of fatigued and injured)). Transport losses cost ~$125/head for dead on arrival and ~$37/head for non-ambulatory pigs, which sum to $46 million yearly.

The National Pork Board has recently funded research to improve pig well-being during handling and transport. The objectives of Chapter 3 were to compare the effects of 2 bedding levels on the (1) pig measures at the time of unloading and (2) transport losses during warm weather for market weight pigs. During warm weather, incorrect bedding levels on a trailer transporting market weight swine may result in heat stress, fatigue, and death. Two experiments were conducted in June and July 2011; Experiment 1 used 80 loads (n = 13,887 pigs) to determine the effects of two bedding levels (3- or six 22.7 kg, 0.2 m3 bags of wood shavings/trailer) on pig measures (surface temperature, vocalizations, slips and falls, and stress signs). Experiment 2 used 131 loads (n = 22,917 pigs) to determine the effects of bedding on transport losses (dead, sum of dead- and euthanized- on arrival; non-ambulatory, sum of fatigued and injured; total transport losses sum of dead and non-ambulatory). Bedding did not affect surface temperature, vocalizations, or slips and falls (P = 0.58, P = 0.50, and P = 0.28, respectively). However, pigs transported on 6 bags/trailer had 1.5 % more stress signs than pigs transported on 3 bags/trailer (P < 0.01). The relationship was weak (R2 = 0.26). No differences were observed between bedding levels for non-ambulatory, dead, or total transport losses (P = 0.10, P = 0.67, and P = 0.34, respectively). Within the context of these experiments there was no evidence of deleterious effects on pig measures or transport losses. However, using more bedding would cost the industry more. Therefore, 3 bags of bedding/trailer may be used when transporting market weight pigs during warm weather in the Midwestern U.S.

Chapter 4 objectives were to compare the effects of 4 sprinkling methods used on trailers transporting market weight pigs on (1) pig measures at the time of unloading and (2) transport losses at the plant. This study was conducted in July of 2012 in Iowa, in WARM (< 26.7 °C) and HOT (≥ 26.7 °C) weather. Four sprinkling methods were compared, with one treatment being randomly assigned to each load: Control (not applied in HOT weather), pigs only, bedding only, or pigs and bedding. Experiment 1 used 51 loads in WARM- and 86 loads in HOT weather to determine the effects of sprinkling method on pig measures (surface temperature, vocalizations, slips and falls, and stress signs). Experiment 2 used 82 loads in WARM- and 54 loads in HOT weather to determine the effects of sprinkling on transport losses (non-ambulatory, dead, and total transport losses). Experiment 1 found that, in WARM weather, there were no differences between sprinkling treatments for surface temperature, vocalizations, or slips and falls (P ≥ 0.18). However, stress signs were 2 % greater for the pigs and bedding- than for the control treatment (P = 0.03). Experiment 2 found, that in WARM and HOT weather, sprinkling did not affect non-ambulatory, dead, or total transport losses (P ≥ 0.18). Therefore, it is only necessary to sprinkle the pigs, but not the bedding, when transporting market weight pigs during WARM and HOT weather in the Midwestern U.S.

Based on these results, 3 bags of bedding/trailer could be used instead of 6 when transporting pigs in June and July in Iowa. Using less bedding could save both money and potentially decreasing the industry's impact on the environment. The overall conclusion of the sprinkling study was that the current industry practice of sprinkling only the pigs should be continued in July in Iowa. However, bedding should not be wetted.