Piepers S, De Vliegher S, de Kruif A, Opsomer G, Barkema H W
Department of Reproduction, Obstetrics, and Herd Health, Ghent University, Salisburylaan 133, 9820 Merelbeke, Belgium.
Vet Microbiol. 2009 Feb 16;134(1-2):113-20. doi: 10.1016/j.vetmic.2008.09.017. Epub 2008 Sep 12.
Dairy heifers represent the future of a dairy herd, and are expected to freshen with a healthy and well-developed udder, capable of producing an optimal amount of high quality milk. A high proportion of heifers have infected mammary quarters at calving, with coagulase-negative staphylococci (CNS) being the most common cause. Staphylococcus aureus and environmental pathogens are also found. The aim of this paper is to summarize how intramammary infections during (late) gestation and early lactation impair the development of the mammary gland and negatively affect future udder health and milk production. Heifers calving with either subclinical or clinical mastitis are also at a higher risk to be culled in first lactation. The magnitude of the effect is most likely related to the virulence of the causative pathogen, the persistence of the infection when milk production has started, and the time of onset of infection. Histological changes in udder tissue from quarters infected with S. aureus are more pronounced than those in udder tissue from CNS-infected quarters. The longer the infections exist and the longer they persist into lactation, the larger the impact on heifers' future udder health and milk production will be. In general, CNS infections are cleared early in lactation and some studies show that CNS do not have a large impact on future milk production and udder health. Future research should elucidate to what extent pathogen-specific as well as host-related factors affect the persistence of IMI in early lactating heifers.
奶牛小母牛代表着奶牛群的未来，人们期望它们产犊时乳房健康且发育良好，能够产出适量的优质牛奶。很大一部分小母牛在产犊时乳腺受到感染，其中凝固酶阴性葡萄球菌（CNS）是最常见的病因。也会发现金黄色葡萄球菌和环境病原体。本文的目的是总结妊娠后期和泌乳早期的乳房内感染如何损害乳腺发育，并对未来的乳房健康和产奶量产生负面影响。产犊时患有亚临床或临床乳腺炎的小母牛在第一个泌乳期被淘汰的风险也更高。影响的程度很可能与致病病原体的毒力、产奶开始后感染的持续时间以及感染的起始时间有关。感染金黄色葡萄球菌的乳腺组织的组织学变化比感染CNS的乳腺组织更明显。感染存在的时间越长，持续到泌乳期的时间越长，对小母牛未来乳房健康和产奶量的影响就越大。一般来说，CNS感染在泌乳早期就会清除，一些研究表明CNS对未来的产奶量和乳房健康影响不大。未来的研究应该阐明病原体特异性因素以及宿主相关因素在多大程度上影响早期泌乳小母牛乳房内感染的持续时间。
