Effect of short road journeys on behaviour and some blood variables related to welfare in young bulls

Many studies have focused on the transport of cattle to fattening farms or to slaughterhouses but there is little information concerning the transport of young bulls delivered to the genetic test stations for selection. Due to the high expected value of young AI candidate bulls, their transport conditions could be very different from those intended for other cattle categories. The objective of the present study was to examine the effect of transport on behavioural response and on some blood variables of 26 young Holstein bulls (mean weight kg 278±64) before, during and after short journeys (duration <8h) to a genetic test centre. Behavioural patterns such as agonistic and affiliative interactions, environmental and conspecific explorative behaviour were recorded by means of an instantaneous sampling method at the farms of origin, into the truck and at the genetic test station. Moreover, standing orientation and postures during transport were recorded. Blood samples were collected by jugular venipuncture before transport (−4 days, T−4), immediately after transport (day 0, T0) and at 4 days (T+4) relative to time day 0. The space allowance during transport, ranging from 1.50m2 to 3.75m2 per head, enabled the animals to move quite freely and adopt comfortable positions. Young bulls did not show any preferences in their standing orientation during journeys and they were observed in a lying position for short time periods; they were also observed to ruminate, especially during the stationary periods of the journey. Mixing of animals during journeys did not affect their behaviour. The agonistic behaviour rate was higher during transport (P=0.049) and in the first two hours after unloading (P=0.003) than on the rearing farms. Four days after transport, agonistic behaviour decreased compared to the level observed during the first two hours after unloading (P=0.003), whereas affiliative behaviours increased (P=0.023); however, since the hourly rate of agonistic interactions remained higher than the rate observed on the farms of origin (P=0.001), we postulate that hierarchical relationships were not well established yet. After unloading, all animals spent more time interacting with others than exploring their new pen. Plasma glucose and non-esterified fatty acid (NEFA) concentrations both increased significantly after transport. There were no changes in the activity of plasma creatine kinase (CK) after transport, suggesting that the journeys did not cause physical exertion. The results indicate that the transport conditions adopted for the AI candidate bulls only slightly affected the behavioural response and blood variables examined here and could be considered satisfactory for their welfare.