Calsamiglia M, Fraile L, Espinal A, Cuxart A, Seminati C, Martín M, Mateu E, Domingo M, Segalés J
Centre de Recerca en Sanitat Animal, Edifici CReSA, Universitat Autònoma de Barcelona, 08193 Bellaterra, Barcelona, Spain.
Res Vet Sci. 2007 Jun;82(3):299-304. doi: 10.1016/j.rvsc.2006.08.007. Epub 2006 Oct 24.
Previous studies have described a "litter effect" associated with mortality in postweaning multisystemic wasting syndrome (PMWS) affected farms. The main objective of this study was to evaluate litter mortality in different PMWS affected farms and to characterize it in relation to three variables of the sow: parity, porcine circovirus type 2 (PCV2) infectious status and PCV2 antibody titres. The study was performed in seven farms that experienced PMWS in nurseries and/or fattening areas. Fifteen sows from each farm were randomly selected from the same farrowing batch. Serum samples were analyzed for antibodies to PCV2 and for genomic detection of PCV2. Four piglets from each sow (60 piglets per farm) were selected and ear-tagged at birth. Out of 420 initial piglets, 104 (25%) died. Sixty three of them (60%) were necropsied, and 40 (63%) diagnosed as PMWS based on case definition criteria. Our results show that sow PCV2 viremia was significantly related to piglet mortality since more piglets per litter died from viremic than from non-viremic sows. Additionally, a significantly greater proportion of animals died from sows that had low antibody titres against PCV2 (39% vs. 18% from sows with medium to high antibody titres). The present study, of exploratory nature, confirms previous results and further characterizes the so called "litter effect" by establishing that the sow PCV2 status had a significant effect on litter mortality in PMWS affected farms.
先前的研究描述了与受断奶后多系统消耗综合征（PMWS）影响的猪场死亡率相关的“窝效应”。本研究的主要目的是评估不同受PMWS影响猪场的仔猪死亡率，并根据母猪的三个变量对其进行特征描述：胎次、2型猪圆环病毒（PCV2）感染状况和PCV2抗体滴度。该研究在七个在保育和/或育肥区出现PMWS的猪场进行。从每个猪场的同一批次分娩母猪中随机选取15头母猪。对血清样本进行PCV2抗体分析和PCV2基因组检测。从每头母猪中选取4头仔猪（每个猪场60头仔猪），在出生时进行耳标标记。在420头初始仔猪中，104头（25%）死亡。其中63头（60%）进行了尸检，40头（63%）根据病例定义标准被诊断为PMWS。我们的结果表明，母猪PCV2病毒血症与仔猪死亡率显著相关，因为每窝中死于病毒血症母猪的仔猪比死于非病毒血症母猪的仔猪更多。此外，死于PCV2抗体滴度低的母猪的动物比例显著更高（39%，而抗体滴度中到高的母猪为18%）。本研究具有探索性质，证实了先前的结果，并通过确定母猪PCV2状态对受PMWS影响猪场的仔猪死亡率有显著影响，进一步描述了所谓的“窝效应”。
