The effect of transportation duration on lying behavior in young surplus dairy calves.

Surplus dairy calves are commonly transported long distances from dairy farms to calf-raising facilities and livestock auctions. Current calf transportation research mainly describes physiological changes resulting from transportation. However, few studies have described the impact of transportation on calf behavior. The main objective of this study was to determine the effect of different durations of transportation (6, 12, and 16 h) on lying time and bouts in surplus dairy calves. A secondary objective of this study was to investigate if calf age affected lying behavior around transportation. Surplus dairy calves (n = 175) were transported in 7 cohorts from 5 commercial dairy farms in Ontario to a single veal facility. On the day of transportation (d 0), calves were randomly assigned to one of 3 treatment groups: 1) 6 h (n = 60), 2) 12 h (n = 58), and 3) 16 h (n = 57) of continuous transportation by road. Calf lying and standing behavior was recorded using HOBO data loggers. Daily lying time (h/d) and bouts (no./d) were assessed from -1 to 3 d relative to transportation. The total time spent lying during transportation was assessed as the percentage of time lying (min lying/total min on the trailer × 100) from the time each calf was loaded onto the trailer until the time each calf was unloaded at the veal facility (n = 167). On the day of transportation (d 0), calves transported for 12 and 16 h spent less time lying (6 h: 17.1 h/d; 12 h: 15.9 h/d; 16 h: 15.0 h/d) and had more lying bouts (6 h: 21.9 bouts/d; 12 h: 25.8 bouts/d; 16 h: 29.8 bouts/d) compared with those transported for 6 h. On the day after transportation (d 1), calves transported for 16 h spent more time lying down than calves transported for 6 h (19.9 h/d vs. 18.8 h/d, respectively). In addition, during transportation, calves transported for 12 h and 16 h spent 5.8% and 7.6% more time lying down, respectively, than calves transported for 6 h. On each day relative to transportation (d -1 to 3), younger calves (2 d to 5 d) spent a greater amount of time lying down than older calves (6 d to 19 d) and, overall, had a greater number of lying bouts. The results of this study suggest that longer durations of transportation have an impact on the lying behavior of surplus dairy calves resulting in more fatigue during and after the journey, and therefore, potentially have negative implications on calf welfare. Additionally, longer durations of transportation may be more impactful on younger calves than older calves.