仔猪断奶前死亡率（PWM）是养猪业的一个重要繁殖指标，可影响畜群的生产力。了解造成仔猪PWM的原因对改善动物福利、降低生产损失、提高养殖利润都是非常重要的。本项研究的主要目的是总结最重要的造成的仔猪PWM的非感染因素，及阐述在商业养殖条件下影响这些的主要因素。

仔猪PWM是一个多因子过程，出生时体重偏小，再加上体能储存较少、不成熟的免疫系统，使得它们更怕冷、更易饥饿、或易被母猪挤压。一般来讲，造成仔猪PWM的因素可分成3类：仔猪（如出生重、活力、性别）、母猪（如初乳、胎次、母体应激、母猪营养）、环境（如季节、温度、栏舍、管理）。

出生重可直接影响体温调节能力、生长速度，故是影响仔猪存活率的最具决定性因素。仔猪活力与存活率、生长速度也有关系，且强烈受分娩过程中缺氧程度影响。另外，仔猪PWM还有性别特点，公猪更易死亡。新生仔猪高度依赖于初乳作为体温调节和生长的能量来源，获得被动免疫对其存活也是非常关键地。但是，母猪胎次对仔猪PWM表现一种相反影响，还需进一步研究。适度的母猪舒适感对于降低分娩过程中母体应激也是很重要的，还可降低对仔猪的负面影响及挤压风险。母猪的营养可影响胎儿发育、出生重、初乳/常乳产量。最后，环境温度对仔猪存活也有显著影响，因为仔猪更易遭受冷应激。分娩舍所使用的栏舍可影响挤压发生率。

将限位与不限位结合起来的新型栏舍设计取得了满意的结果。分娩过程中生产者可执行不同的管理策略来控制PWM。但是对口服营养补充剂、交叉饲喂、看护母猪系统、人工饲喂仔猪等这些技术，还缺乏科学依赖，还需作更多的研究。

附原文：

Non-infectious causes of pre-weaning mortality in piglets

Piglet pre-weaning mortality （PWM） is one of the major reproductive components that affects herd productivity in the swine industry. Knowledge of factors that influence piglet PWM are important to improve animal welfare, to reduce production loss and to raise profits in commercial herds. The main objective of the present work was to review the most important non-infectious causes of piglet PWM and to present the main factors influencing them under commercial conditions.

Piglet pre-weaning mortality is a multifactorial process, the small size of piglets at birth, together with their low body energy storage and their immature immune system, make them prone to chilling, starving, or being crushed by the sow. In general, factors causing piglet PWM are usually classified into three major groups: piglet （i.e., birth weight, vitality, and gender）， sow （i.e., colostrum, parity, maternal stress, and sow nutrition）， and environmental factors （i.e., season and temperature, housing, and management）。

Birth weight is the most determinant factor for piglet survival with direct impact on thermoregulatory capacity and growth; piglet vitality is also correlated with survival and growth and is strongly influenced by the degree of intra-partum hypoxia suffered by the piglet; additionally, piglet PWM appears to be sex-biased, with males showing greater susceptibility to causal mortality factors. Newborn piglets are highly dependent on colostrum to use it as energy substrate for thermoregulation and growth, and also to acquire passive immunity crucial for their future survival; however, sows' parity is a factor with contradictory effect on PWM which requires further research; a proper sows' comfort is also important for maternal stress around farrowing might have a negative impact on offsprings development and also increases the risk of crushing; sows' nutrition will influence foetal development and piglet birth weight, and is determinant to ensure a proper colostrum/milk production. Finally, ambient temperature has an important impact on piglet survival because piglets are very sensitive to cold stress. The housing system used in the farrowing room seems to influence the incidence of crushing.

Promising results have been obtained using recent designs that combine initial confinement of the sow with the subsequent ability to move within the same pen. Different management strategies to deal with PWM are usually performed by producers around farrowing. However, there is a lack of scientific evidence on techniques, such as oral supplementation of piglets, cross-fostering, nurse sow systems, or artificial rearing of piglets, and further research should be of interest.