The influence of different feeding arrangements and food type on competition at feeding in pregnant sows

Abstract

The effects of different feeding arrangements (body, shoulder and no partitions between sows) and type of food (wet vs. dry) on aggressive competition at feeding were investigated. Six groups of six pregnant sows were subjected to all the six treatments, and the order of treatments were rotated systematically. In the last 2 days of each treatment period (lasting for 9 days in total), the behaviour of the sows was video recorded for 60 min from the start of feeding. Aggressive behaviours (bite towards head/shoulder and body, bite towards vulva, push, threat, head knock), frequency of changing position at the trough (displacements and voluntary changes of position) and the time at trough were recorded. In the analysis, the observation period was divided into feeding (0–15) and post feeding (45–60 min). On dry feeding, increasing length of partitions resulted in a significant reduction in the number of bites, total aggressive behaviours and displacements at the trough and an increased time at trough. The number of bites and total aggressive behaviours were lower on wet than on dry feeding in the simple feeding arrangements (i.e., shoulder or no partitions), but there were no significant differences when body partitions were used. On wet feeding, there were no significant differences between body and shoulder partitions concerning the number of bites, nor were there any significant differences between feeding arrangements concerning the time at trough or the number of displacements at trough when wet food was used. The top ranked sows received less bites and displacements and spent more time at trough than the other sows in all feeding arrangements, whereas the lower ranked sows were less subjected to aggression and displacements and spent more time at the trough as the length of partitions increased. In conclusion, a feeding arrangement with body partitions resulted in the least aggression and displacements at trough compared to a situation with shoulder or no partitions. On wet feeding, however, the amount of aggression did not differ between shoulder and body partitions, and the time at trough appeared to be almost equal in all feeding arrangements. Simple feeding systems may thus be used without increasing the amount of aggression or reducing the eating time when wet food is used. However, the differences in eating time, aggression received and displacements between sows of different rank order will increase with decreasing length of partitions at the trough, and in a situation without partitions the low-ranking individuals may suffer from a reduced food intake. Body partitions is therefore still a more recommendable feeding system.