Strait Erin L, Hawkins Peggy Anne, Wilson Warren D
Department of Veterinary Diagnostic and Production Animal Medicine, College of Veterinary Medicine, Iowa State University, Ames, 50011, USA.
J Am Vet Med Assoc. 2012 Dec 15;241(12):1666-7. doi: 10.2460/javma.241.12.1666.
A sudden onset of extreme dysgalactia in gilts and sows in a 1,000-head farrow-to-wean herd was observed in December 2009. Signs of dysgalactia were identified in sows beginning 1 day after parturition and lasted 4 to 6 days. This resulted in a mean piglet preweaning mortality rate of 18% because of starvation.
Sows were neither off feed nor febrile. Udders were not inflamed or congested. Feed sample analysis did not find ergotamine, mycotoxin contamination, or ration formulation errors. Management practices were acceptable. Piglets attempted to stimulate milk production but none was elicited. Oxytocin (20 U) caused milk ejection but the effect was short-lived. Blood samples from sows with affected litters were positive for Mycoplasma suis (formerly Eperythrozoon suis) by PCR assay, and blood samples from sows with unaffected litters were negative.
Chlortetracycline fed to the entire sow herd at 22 mg/kg/d (10 mg/lb/d) for 2 weeks resulted in a near complete absence of dysgalactia in sows farrowing within 5 weeks after the start of treatment. Dysgalactia did occur in sows that received chlortetracycline > 5 weeks prior to farrowing. Currently, gestating sows and gilts receive chlortetracycline in feed at a dosage of 22 mg/kg/d for 2 weeks beginning 3 weeks prior to farrowing.
M suis is spread primarily by blood contact from animal to animal, and diagnosis of infection with this organism can be easily missed by means of standard diagnostic protocols unless PCR assays or specific stains are used. Therefore, its current prevalence and impact are likely to be greatly underestimated.
2009年12月，在一个有1000头母猪从产仔到断奶的猪群中，观察到后备母猪和经产母猪突然出现严重的泌乳障碍。泌乳障碍的症状在母猪分娩后1天开始出现，持续4至6天。这导致仔猪因饥饿而断奶前平均死亡率达到18%。
母猪既没有食欲减退也没有发热。乳房没有发炎或充血。饲料样本分析未发现麦角胺、霉菌毒素污染或日粮配方错误。管理措施是可接受的。仔猪试图刺激乳汁分泌，但没有成功。催产素（20单位）可引起排乳，但效果短暂。通过聚合酶链反应（PCR）检测，受影响仔猪窝的母猪血液样本猪支原体（原猪附红细胞体）呈阳性，未受影响仔猪窝的母猪血液样本呈阴性。
以22毫克/千克/天（10毫克/磅/天）的剂量给整个母猪群投喂金霉素，持续2周，结果在开始治疗后5周内分娩的母猪几乎完全没有出现泌乳障碍。在分娩前5周以上接受金霉素治疗的母猪确实出现了泌乳障碍。目前，妊娠母猪和后备母猪在分娩前3周开始，在饲料中按22毫克/千克/天的剂量接受金霉素治疗，持续2周。
猪支原体主要通过动物之间的血液接触传播，除非使用PCR检测或特异性染色，否则通过标准诊断方案很容易漏诊这种病原体的感染。因此，其目前的流行程度和影响可能被大大低估。
