Housing of Cull Sows in the Hours before Transport to the Abattoir-An Initial Description of Sow Behaviour While Waiting in a Transfer Vehicle

In modern pig production, sows are transported by road to abattoirs. For reasons of biosecurity, commercial trucks may have limited access to farms. According to Danish regulations, sows can be kept in stationary transfer vehicles away from the farm for up to two hours before being loaded onto the commercial truck. We aimed to describe the behaviour of sows in transfer vehicles. This preliminary, exploratory study included data from 11 loads from a total of six Danish sow herds. Selection of animals to be slaughtered was done by the farmers. Clinical registrations were made before collection of the sows, after which they (in groups of 7-13) were mixed and moved to the transfer vehicle (median stocking density: 1.2 sow/m²), and driven a short distance to a public road. The duration of the stays in the transfer vehicles before being loaded onto the commercial trucks ranged from 6-59 min. During this period, the median frequency of aggressive interactions per load was 18 (range: 4-65), whereas the median frequency of lying per load was 1 (range: 0-23). The duration of the stay correlated positively with the frequency of aggressive interactions (r_s = 0.89; n = 11; p < 0.001) and with the frequency of lying (r_s = 0.62; n = 11; p < 0.05). Frequency of aggressive interactions correlated positively with the temperature inside the transfer vehicle (r_s = 0.89; n = 7; p < 0.001). These preliminary results are the first to describe the behaviour of cull sows during waiting in transfer vehicles, and may suggest that this period can be challenging for sow welfare, especially for longer stays and during hot days.