Determining effects of transport factors on transport loss in a commercial production system

摘要

Extensive studies have shown that transportation loss is multi-factorial, however, few have evaluated the utility of pre-transport pig evaluations in determining the post-transport welfare of pigs. The objective of this study was to determine if transport factors, as well as the pre-transport condition of the pigs, in a commercial swine operation played a role in transport losses. In this study, 69 Load Site Assessments were completed at 26 different barns, with different 24 truck drivers, representing 11,482 pigs. Pigs were located in the eastern corn-belt within 300 miles from the harvesting facility. Load Site Assessment forms were created to collect objective data on pig, facility design, and trailers, based on results from a previous project efficiency study.1 Stressed pigs were identified in the barn during load out before entering the trailer as red (open mouth breathing, muscle tremors, and or skin discoloration), or only green (only high pitch vocalization for greater than two seconds), pigs were marked exclusively in one of the categories. Marked pigs were observed through the packing plant and the number of red or green dead at arrival (DOA) and non-ambulatory at arrival or in the plant (NA) were recorded. Facility differences includedan observation of the angle of the loading chute (greater or less than 20 degrees), as well as the number of times a group of pigs stopped when encouraged forward motion during load out, and the average size of loading groups. Standard least squared regression models were used to evaluate the effect of pig and pre-transport factors on the number of pigs marked as red prior to transport, as well as post-transport DOA and NA, usingJMP v9.0. A total of 317 pigs were marked as red (2.8%) and 20 as green (0.2%) prior to transport (Table 1). More pigs were marked red prior to transport when loadingramps were greater than 20° (2.9 ± 0.83 vs 5.7 ± 0.68, P = 0.02), and the number of pigs marked red increased by 0.14 ± 0.06 for every degree increase in ambient temperature during loading, within the range of 43 to 88 °F that occurred in this study(P = 0.02). Overall, 0.2% pigs were DOA, and 0.3% were NA. Of the 317 pigs marked red prior to transport, 7 (2.2%) were DOA and 1 (0.3%) were NA. However, 25% of DOA pigs were pigs that had been marked red prior to transport and pigs marked red prior totransport had 11.7 times the risk or being DOA compared to pigs that were not matked prior to transport (95 % CI = 5.01 to 27.3; P < 0.01). Zero of the 20 pigs marked green prior to transport were DOA or NA following transport. There was no statisticalassociation between the number of red or green pigs in a load and the number of DOA or NA pigs after transport. Thete was a tendency for DOA pigs to increase when the loading tamp was greater than 20° (0.13 ± 0.17 vs 0.58 ± 0.15, P = 0.07). The numberof NA pigs tended to increase by 0.09 ± 0.05 for every increase in lbs/ft2 within the range of 44 to 62 lbs/ft2 in the current study (P = 0.08). The findings of this study are consistent with previous transport data on angle of the loading chute.2 Thestudy was designed to be applicable to provide support for data to make adjustments to loading procedures; such as ramp design, space allowance, and decreasing the opportunities for physical and vocal signs of stress during load out.