Transportation can be stressful for pigs of all ages, but data on how weaned piglets are affected by current transport practices are limited. Assuring that all pigs survive transport is important to the bottom line of all hog operations.
Assuming that healthy pigs are loaded onto the truck, if there is a relationship between a transport practice and increased mortality, it indicates a risk factor that could be reviewed for improvement.
The present study identified the risk of mortality (dead on arrival) for weaned piglets during transport increases as transport distance increases. This risk of mortality is further exacerbated when long-distance transport (more than 14 hours) occurs in temperature extremes, i.e., very cold to cold temperature conditions (below -10 degrees C to 5 degrees C), and the type of truck that is used (straight deck versus potbelly).
There is an interactive effect of distance and temperature, and truck type and temperature, on the risk for dead on arrival. This indicates that for such journeys to occur, improved climatic control of trucks needs to be achieved.
Researchers at the University of Saskatchewan, the Prairie Swine Centre Inc. and the University of Guelph collaborated on a study that took a retrospective analysis of industry transport records from shipments of weaned piglets transported by road originating in Canada.
The dataset provides insights into what are typical current transport practices, and what the impact of current transport practices on piglet mortality is.
Through analyzing the effect of risk factors on the piglet transport, this work identifies areas that require industry focus to reduce piglet mortality and improve the welfare of pigs traveling by road.
There is little available knowledge on how commercial transport practices influence piglet welfare. Records of piglet mortality during transport are collected as a measure of importance to animal welfare and production.
The objective of this study was to identify risk factors for mortality in newly weaned piglets transported by road within Canada, by retrospective analysis of records from commercial shipments.
A total of 6,692 transport records spanning a four-year period (2014-18) were collected from five companies: three hog production companies and two livestock transporters. Researchers looked at the effect distance had on piglets, dividing and classifying trips accordingly:
* less than 500 kilometers, "short," <6 hours
* 500 to 1,250 kilometers, "medium," >6-14 hours
* 1,250 to 2,500 kilometers, "long," >14-28 hours
* more than 2,500 kilometers, "very long," >28-36 hours
Ambient temperature was also categorized:
* below -10 degrees C, "very cold"
* -10 degrees C to 5 degrees C, "cold"
* 5 degrees C to 25 degrees C, "mild"
* Above 25 degrees C, "warm"
Researchers also looked at the how the piglet weight; trailer type, whether potbelly or straight deck; the eight trucking companies; and the 62 barns of origin played a role in the number of weaned pigs that were dead on arrival, using a mixed negative binomial model.
The average load size was 1,119 pigs, with a range from a minimum of 29 to a maximum of 3,433 pigs per load. The predicted number of DOA increased with increasing transport distance, and temperature interacted with distance to influence mortality.
The predicted DOA counts (piglet loss per trailer; mean ± standard error, P<0.05), for long transport in very cold temperatures were greater than for long transport in mild temperatures (7.30 ± 3.16, and 1.47 ± 0.55, respectively). The DOA counts for trips in potbelly trailers were greater in very cold (2.43 ± 1.02) and cold (1.33 ± 0.53) temperatures, compared to similar journeys in a straight deck trailer (very cold, 0.61 ± 0.29; cold, 0.11 ± 0.08).
There is an increased risk of DOA for weaned piglets as distance traveled increases. Risk of mortality is greater for long-distance transport in very cold temperatures than in mild temperatures, and under cold or very cold conditions in a potbelly trailer than in a straight deck.
Trailer design with climate-control capabilities is an area for focus, especially for long-distance journeys.
Based on the results of the retrospective analysis, long and very long trips experience mortality on 42% and 45% of loads, respectively, across seasons, with an average mortality of 0.135% (1.3 pigs per load).
During the very cold weather, data suggest mortality increases to approximately 0.7% (seven pigs per load) for long and very long trips.
This increase in mortality would result in lost revenue opportunity of $200 to $300 per load for pigs shipped during a very cold time frame and over a long distance.
This project was financed by the Saskatchewan Agriculture Development Fund. The researchers thank the companies that supplied the data.