Establishing Bedding Requirements on Trailers Transporting Market Weight Pigs in Warm Weather.

During warm weather, incorrect bedding levels on a trailer transporting market weight pigs may result in heat stress, fatigue, and death. Two experiments were conducted in June and July of 2011; Experiment 1 used 80 loads (n = 13,887 pigs) to determine the effects of two bedding levels (3 (68.1 kg) or 6 bags (136.2 kg) of wood shavings/trailer [each bag contained 22.7 kg, 0.2 m³]) 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 (3 vs. 6 bags) 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). 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, bedding level did not result in deleterious effects on pig measures or transport losses. However, using more bedding may result in higher costs to the industry. Therefore, 3 bags of bedding/trailer may be used when transporting market weight pigs during warm weather in the Midwestern U.S.