Time of weaning has more of an effect on certain stress markers than length of transport, scientist says
By Jackie Clark
Researchers are collaborating to analyse data from a swine transportation study comparing health and welfare of weaned piglets.
“We collected data in 2019 with long and short transports,” Dr. Jennifer Brown, research scientist at the Prairie Swine Centre, told Farms.com. “We followed four loads going from Saskatchewan to nursery barns in Ontario, so roughly 36 hours, right at the upper limit of the previous transport maximum duration. … We compared those to a short duration transport, roughly 90 minutes within Ontario.”
The researchers recorded piglet weight, lesion scores, lameness and took blood samples before and after transportation. They also attached heart rate monitors to a subset of piglets and monitored temperature and humidity on the trailers. Finally, cameras captured pig behaviour during transport, Brown explained.
The researchers returned to nurseries 72 hours later to score and weigh piglets again, she added.
A PhD student is still working to analyse much of the data, but some initial findings were surprising.
“It’s presumed with a long transport that you would see more indicators of stress, and actually we really didn’t,” Brown said. Blood indicators of stress, such as like white blood cells and cortisol, were all higher in short duration pigs compared to long duration after transport.
This is likely “because they had that intense experience of being weaned and then loaded and unloaded, whereas the long duration pigs had time on the trailer to settle down, presumably,” Brown explained.
Weaning timing had a greater effect on certain parameters than transport duration, she added.
“With those long loads, in order to fill a transport trailer and take all those pigs from Saskatchewan to Ontario, it’s multiple weaning dates, so those pigs are gathered together in a nursery at the sow barn before they’re loaded,” she explained. The long duration piglets were weaned prior to loading, whereas piglets in the short transport treatment are taken directly off the sow and loaded onto the trailer.
“When we look at the lesions, those short duration piglets, because they hadn’t been already mixed before they went to transport, they had lower lesion scores before transport,” Brown explained. “The long duration pigs were mixed in the nursery, so they were already into fighting and that kind of thing and so the had more lesions before they went on the trailer.”
However, upon arrival there were no differences between tail lesion scores of the two groups, and higher lameness in the short duration group.
The short duration transport group experienced more intense and acute stress “whereas the long duration piglets had over a day to recover on the trailer and then walked off nicely,” she said.
After 72 hours in the nursery barn, the short duration piglets had more lesions because the long duration ones were over their weaning aggression, she added.
When looking at weight, piglets in the long transport treatment did experience a drop post-transport, which was unsurprising, explained Brown. However, 72 hours later there was no difference in weight based on length of transport. No difference existed in dehydration of piglets between transport lengths and “all the values were within what’s considered the normal range for nursery pigs.”
Overall, the researchers found “no flags thus far in our data that show any real problems associated with the long transport which is of course the main concern,” Brown said. “We’re really interested to see now the behaviour measures on the trailers and see how that maybe contributed to some of these results and if that’s going to help us to interpret the welfare of the pigs during transport.”
Future studies may investigate the impact of rest, feed and water provided during long transport to see if new transport regulations will actually result in improved health and welfare for weaner piglets.
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