Spending a minute a day walking amongst finishing pigs can pay dividends at loading and in the packing plant.
Calm, low-stress handling of market hogs depends on a combination of properly designed handling facilities, experience and technique of handlers, and the behavioral response of the pigs to handling.
Pig behavior during handling is thought to depend in large part on their previous experience with humans. One practical recommendation for getting pigs used to moving around people long before they get to the slaughter plant is to “walk the pens” during the growing and finishing phase.
Less than a minute of walking time through the pens each day is thought to have a big impact on pig behavior. But, realistically, if you multiply those few seconds by hundreds of pens in a barn or a site, the time commitment soon tallies hours of a stockman's time each week.
So how much time spent walking the pens is enough to improve pig handling?
Researchers at the University of Guelph and the Ontario Ministry of Agriculture Food and Rural Affairs (OMAFRA) recently set out to answer that question on two commercial farms. Pens on those farms were walked once, twice or three times per week, or not at all, during the 12 weeks prior to marketing.
On Farm 1, five rooms of pigs were tested; each room had 12 pens housing 24 pigs/pen. Three pens in each room were exposed to each of the pen- walking treatments. When walking the pens, a researcher simply entered the pen holding a sorting board and made one circuit around the pen, spending an average of 40 seconds/pen.
On Farm 2, four rooms were used, each room having eight pens of 15 pigs. Two pens in each room were exposed to each of the four pen-walking options. A farm stockperson walked the pens, spending on average 24 seconds/pen.
Behavior was measured in the pigs' home pens, during loading onto trucks and in a crowding pen at a commercial meat packing plant.
Home Pen Behavior
Once each week, the responses of the pigs to the “walker” entering the pens were determined by scoring the percentage of pigs in the pen that rapidly avoided the walker and tried to escape.
At both farms, walking the pens had a significant effect on the pigs' behavior (Figures 1 and 2). All of the pigs showed a reduction in escape behavior over time.
However, pens of pigs that were walked two or three times per week were less inclined to try to escape from the handler moving through the home pen compared to pigs whose pens were walked only once weekly.
By the end of the trials (Weeks 11 & 12), escape behavior was significantly lower in pens walked two or three times compared to those walked only once each week.
Pigs at each farm responded differently, which may have been due to genetics, some other management factors, or the way observers scored the pigs. Still, at both farms, walking the pens at least twice a week had a greater effect on pig behavior.
On Farm 1, the behavior of pigs during loading onto trucks was measured. Three-tiered, potbelly trailers were used to ship the pigs to a commercial slaughter plant.
Researchers were stationed at each segment of the loading process to record how much time it took to move small groups of pigs out of their home pen, down a hallway to the preloading area, out of the preloading area into the loading chute, then through the loading chute and onto the truck. Pigs were marked with different colors according to treatment, but observers were “blind” to treatments.
Figure 3 shows the average amounts of time it took to move pigs through each segment of the loading process for each of the handling treatments. There were no statistical differences between treatments for any of the segments, although there was a tendency for pigs in pens walked two or three times/week to move more quickly out of the preloading area than pigs from pens walked only once/week or not at all.
One factor that had a highly significant effect on loading time was the tier of the truck to which pigs were moved. It took almost twice as long to move pigs up the steep ramp to the top level of the truck as it did to the middle and bottom tiers, regardless of their handling treatment.
Slaughter Plant Behavior
At the slaughter plant, a video camera was positioned over a crowding pen that led into a single file chute. The pigs were observed as plant workers moved batches of pigs from each of the treatment groups through the crowding pen and into the chute. The frequency of jamming at the entrance to the chute and the time it took to empty the crowding pen were recorded.
Handling treatment on the farm significantly reduced the frequency of jamming for pigs from Farm 1, with less jamming occurring for any of the pen-walking treatments compared to pigs whose pens had not been walked.
Similar results were found for the time it took to empty the crowding pen for the pigs from Farm 2. Pigs whose pens had not been walked took about twice as long to move out of the crowding pen than pen-walked pigs.
Regardless of handling treatment, however, the number of pigs put into the crowding pen during handling had a highly significant effect on pig behavior. Overloading the crowding pen resulted in significantly more jamming (Figure 4) and longer times to empty the pen for pigs from both of the farms.
Try for Twice a Week
The data from this study demonstrate how all three factors — facility/truck design, handling technique and pig experience — can significantly affect how pigs respond to humans and to handling at shipping to market.
Walking the pens only once/week for the last 12 weeks prior to shipping had some positive effects on handling at the plant, but walking the pens at least twice/week showed the greatest effects on behavior on the farm.
Ontario Pork and OMAFRA provided funding for this study. The researchers would like to thank the participating producers, truckers and packing plant.
Researchers: Tina Widowski and Jennifer Brown, University of Guelph, Guelph, Ontario, Canada; and Penny Lawlis, Ontario Ministry of Agriculture, Food and Rural Affairs, London, Ontario, Canada. Contact Widowski by phone (519) 824-4120, ext. 52408; fax (519) 836-9835 or e-mail [email protected].