This study established the causes and timing of spontaneous sow deaths in the farrowing units of ten Danish sow herds. Herds participated for seven to 15 months during 2018–19. We received data (production data and detailed information on the sows that died) on a total of 126 sows. Fifty-three sows were necropsied, and tissues were evaluated histopathologically.

Twenty-four percent of the sows died 0–5 days postpartum. The main cause of death in the study was liver lobe torsion, which was diagnosed in 22 of 53 necropsied sows (42%). Deaths caused by liver lobe torsions were less often seen during the 0–5 day postpartum period compared to deaths caused by other reasons (P = 0.002).

Seven of the necropsied sows (13%) died from endotoxaemic shock from retained foetuses. This cause of death was seen in seven of ten herds. These sows typically died 1–3 days postpartum.

Pneumonia accounted for 13% of deaths in the necropsied sows, but the majority of these sows originated from one herd experiencing a respiratory outbreak caused by the introduction of M. hyopneumonia. Less prevalent causes of death in the study were torsion of the intestinal segment (8%), suspected cardiovascular collapse (8%), rupture of blood vessels (uterine and nonuterine) (8%), gastric ulcer (4%), sepsis (2%) and liver abscess (2%).

We concluded that liver lobe torsion needs further attention to establish the background of this surprisingly prevalent cause of death. Furthermore, a need for procedures that ensure efficient farrowing was identified.

本研究确定了十个丹麦母猪群的分娩单元中母猪自发死亡的原因和时间。在 2018-19 年期间，牛群参与了 7 到 15 个月。我们收到了总共 126 头母猪的数据（生产数据和死亡母猪的详细信息）。对 53 头母猪进行尸体剖检，并对组织进行组织病理学评估。

24% 的母猪在产后 0-5 天死亡。研究中的主要死亡原因是肝叶扭转，在 53 头尸体剖检母猪中有 22 头 (42%) 被诊断出肝叶扭转。与其他原因引起的死亡相比，肝叶扭转引起的死亡在产后 0-5 天期间较少见（P  = 0.002）。

七头尸体剖检母猪 (13%) 死于胎儿滞留引起的内毒素休克。这种死因在 10 个牛群中有 7 个出现。这些母猪通常在产后 1-3 天死亡。

肺炎占剖检母猪死亡的 13%，但这些母猪中的大多数来自因引入猪肺炎支原体而引起呼吸道疾病暴发的猪群。研究中不太常见的死亡原因是肠段扭转 (8%)、疑似心血管衰竭 (8%)、血管破裂（子宫和非子宫）（8%）、胃溃疡（4%）、败血症（ 2%) 和肝脓肿 (2%)。

我们得出结论，肝叶扭转需要进一步关注，以确定这一令人惊讶的普遍死亡原因的背景。此外，还确定需要确保有效分娩的程序。