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Effect of rest-stop duration during long-distance transport on indicators of animal welfare in weaned beef calves
Forty newly weaned Angus beef calves (260 ± 32.6 kg) were transported 15 h in a livestock trailer (7.3 m × 2.1 m) on 2 separate d (20 calves per d) to evaluate the effect of rest-stop duration on indicators of calf welfare. Immediately following the 15 h journey all calves were unloaded at a feedlot and randomly assigned to one of the 4 treatments. Treatments included: 0 (Control; C) 5 (RS5), 10 (RS10), or 15 (RS15) h rest periods in pens containing ad libitum access to water and long-stem hay. Following each rest period, calves were reloaded onto the same trailer and taken on another 5 h journey for a total transport event lasting 20 h. Control calves did not have access to feed or water until the end of the 20 h transit event. Behavioral measurements included: loading and unloading scores (fall, aggression, mount, slip, trip, balk and walk, trot or run), animal condition (non-ambulatory, lame, injured, fatigued, wet coat and dirty), number of steps (steps/d), feeding behavior (min/d), standing and lying frequency (no./d) and duration (min/d) during rest periods and at the end of the 20 h transport event . Physiological measurements included: saliva and hair cortisol, total blood cell count and substance P concentrations. All measurements were taken immediately prior to loading and after unloading at the rest stop and the end of the 20 h event. Salivary cortisol was greater (P < 0.01) in C and RS15 than in RS5 and RS10 calves at the end of each rest stop period and the 20 h event. RS15 calves had greater (P = 0.02) salivary cortisol concentrations before and after the last 5 h of transport compared to RS5 and RS10 calves. The RS10 calves spent more (P < 0.01) time lying than any other treatment. No treatment differences (P = 0.14) were observed for feeding duration, although it was numerically lower in RS10 calves. Meal duration following 20 h of transport was lower (P = 0.05) in C calves than all other treatments. The results of this study indicate that provision of a rest stop not greater than 10 h reduces stress in weaned calves as witnessed by reduced salivary cortisol concentration and less time spent lying.
Keywords: resting stop, transport, calves, welfare