Do conditioned calves benefit from a rest following long-haul transport?
By Daniela M. Meléndez, Sonia Marti, Derek B. Haley and Karen S. Schwartzkopf-Genswein
Lethbridge Research and Development Centre, Agriculture and Agri-Food Canada, Lethbridge, Alberta, Canada
Surprisingly, we know very little about the effects of providing beef calves a rest (including feed and water) mid-way through a long-haul (>12 hours) transport. Finding an answer to this question has become more important due to recent changes to the Canadian humane transport regulations implemented by the Canadian Food Inspection Agency (CFIA) in February of this year. The proposed changes state that un-weaned and weaned calves can be transported a maximum of 12 and 36 hours, respectively, before an 8 hour rest is required. To provide producers and policy makers with science-based information we conducted a study evaluating the effects of different rest stop durations after different lengths of transport on indicators of welfare in 7-8-mo-old conditioned beef calves.
In order to isolate the effects of transport, calves were ‘conditioned’ to avoid the effect of weaning, which is known to be a stressful management practice. Calves were weaned, vaccinated, ear tagged, adapted to eating from a feed bunk, and consuming a diet with some grain and to drinking from a water trough, 18 to 26 days before the study started.
We used 320 calves, half of which were transported for 12 hours while the other half were transported for 36 hours. Each of these groups was further divided according to the duration of rest they were given: no rest (0), 4, 8 or 12 hours. After their assigned rest period all calves were transported for an additional 4 hours to their final destination. Blood samples were collected from a subset of calves before and after their initial 12 or 36 hours of transport and the final 4 hours of transport as well as at 7 hours, 2 and 28 days after the 4 hour transport. Blood samples were analyzed to evaluate fat mobilization (increases in response to feed deprivation), muscle damage, acute and chronic stress, inflammation and immune function. The performance indicators we assessed included body weight, average daily gain and shrink, while standing and lying behaviour were evaluated as indicators of calf fatigue.
The calves that were transported for 36 hours had lower body weight, averaged daily gain, and greater shrink and fat mobilization than the 12 hours transported calves. Fat mobilization was greater in calves that received no rest, compared to the calves that received 4, 8 and 12 hours of rest. Overall, there were more indicators of reduced welfare in calves transported for 36 hours than calves transported for 12 hours. The only impact of providing calves with a rest en route, was a reduction in fat mobilization.
Based on these results our research group is currently conducting a study to determine if rest stops are more beneficial to newly weaned than conditioned calves. Further studies should also look at the impacts of rest stops in calves that are transported for more than 4 hours after their rest. Replication of these experiments would also be useful to ensure the consistency of the results and conclusions made from them. At the beginning of March the CFIA announced they would postpone implementation of the new regulations regarding required rest periods until February of 2022, pending the outcome of these studies. Stay tuned!
This research was funded by Agriculture and Agri-Food Canada and the Beef Cattle Research Council through the Canadian Beef Cattle Industry Science Cluster.