Nursing behaviour in lactating sows kept in isolation, in acoustic and visual contact

Abstract Synchronization of nursings occurs between domestic lactating sows housed in one room. This study tested experimentally whether acoustic contact without any possibility to see other sows is sufficient for a high level of nursing synchronization. Secondly, the study investigated whether the possibility to synchronize with other sows affects positively the frequency of nursing, the frequency of milk ejection and the growth rate of sucking piglets. Eleven sets of three lactating sows were observed. One sow of each set (the I sow) spent lactation in an isolated room while the other two were housed in a room with other lactating sows, one of them with acoustic and visual contact with other sows (the C sow), the other in acoustic contact only (the S sow). Nursing behaviour was recorded in these focal sows ( n  = 33) for 6 h on days 7 and 21 of lactation. The S sows had 43% of their nursings synchronized with the C sows ( p