Danger to pigs due to crushing can be reduced by the use of a simulated udder

Sows that lie on their young, pig "crushing", is a significant cause of pig mortality in current production systems. Although mortality rates of pigs in farrowing crates are lower than mortality rates of pigs in pens, loss due to crushing is still estimated to be between 4.8 and 18%. During the first few days after parturition, pigs are highly attracted to the odor of their dam's udder. Thus, our research was designed to move the pigs away from the sow by competing with the sow's udder using a "simulated" udder. Fifteen Yorkshire x Landrace sows and their litters (11.4+/-.78 pigs) were assigned to either a control (C, n = 9) or an experimental group (SU, n = 6). The C pigs had access to a heat lamp, whereas the SU pigs' crate had a simulated udder. Data were collected using time-lapse photography (1 frame/.4 s) for a 3-d duration at the initiation of farrowing. When a sow stood, data were recorded by 1-min scan samples to record the number of pigs using either the heat lamp or the simulated udder. In addition, stillborn pigs, pig crushing, and death by other means also were recorded. Data were analyzed by 12-h periods using generalized estimating equations. Results indicate that from 12 to 72 h postpartum, excluding 24 to 36 h postpartum, the estimated probability that pigs were in a safe area (simulated udder or heat lamp) was .89 for SU pigs, compared with only .72 for C pigs (P = .005). During the 24- to 36-h period, it was more probable to find pigs on a simulated udder (.77) than under only a heat lamp (.61, P = .016). Stillborn pigs, pig crushing, and death by other means were not different between treatments (mean = .87, .60, 1.2; P>.20). The simulated udder drew pigs away from the sow's udder better than heat lamps alone. Considering these findings, mortality of pigs due to crushing may be decreased substantially using a simulated udder. These results are promising, but further refinement should be done, including improved udder design and investigation of the attractiveness of various stimuli.