Lay D C, Haussmann M F, Buchanan H S, Daniels M J
Department of Animal Science, Iowa State University, Ames 50011-3150, USA.
J Anim Sci. 1999 Aug;77(8):2060-4. doi: 10.2527/1999.7782060x.
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.
母猪压死仔猪，即“踩压”，是当前养殖系统中仔猪死亡的一个重要原因。尽管产仔栏中仔猪的死亡率低于猪舍中仔猪的死亡率，但据估计，因踩压造成的损失仍在4.8%至18%之间。在分娩后的头几天，仔猪对母猪乳房的气味有很强的吸引力。因此，我们的研究旨在通过使用“模拟”乳房与母猪乳房竞争，将仔猪从母猪身边移开。15头约克夏×长白母猪及其仔猪（11.4±0.78头）被分为对照组（C，n = 9）或实验组（SU，n = 6）。对照组仔猪可以使用加热灯，而实验组仔猪的产仔栏中有一个模拟乳房。在分娩开始时，使用延时摄影（1帧/0.4秒）持续3天收集数据。当母猪站立时，通过1分钟扫描取样记录使用加热灯或模拟乳房的仔猪数量。此外，还记录了死产仔猪、被踩压仔猪以及其他方式死亡的仔猪。使用广义估计方程按12小时时间段对数据进行分析。结果表明，产后12至72小时，不包括产后24至36小时，实验组仔猪处于安全区域（模拟乳房或加热灯）的估计概率为0.89，而对照组仔猪仅为0.72（P = 0.005）。在24至36小时期间，仔猪在模拟乳房上的可能性（0.77）高于仅在加热灯下的可能性（0.61，P = 0.016）。各处理组之间死产仔猪、被踩压仔猪以及其他方式死亡的情况没有差异（平均值分别为0.87、0.60、1.2；P>0.20）。模拟乳房比单独的加热灯更能将仔猪从母猪乳房旁引开。考虑到这些发现，使用模拟乳房可能会大幅降低仔猪因踩压造成的死亡率。这些结果很有前景，但仍需进一步改进，包括改进乳房设计以及研究各种刺激因素的吸引力。
