奶牛产后子宫感染与子宫免疫

非特异性子宫感染会降低奶牛的生产性能和奶牛场的潜在效益。发生子宫感染时常并发感染化脓性放线杆菌或混合感染其他细菌。当从产后21 d的奶牛子宫液中分离到化脓性放线杆菌时,说明奶牛发生了严重的子宫内膜炎,并且将导致产后第一个发情期不孕。然而引起子宫感染的确切原因尚不清楚,但可以肯定与多种因素有关。发生难产、胎衣不下、怀有双胎或死胎以及患有各种代谢紊乱疾病的奶牛比其他奶牛更容易发生子宫感染。分娩前后异常的免疫功能更容易导致发生严重的子宫感染。子宫感染一般不会引起奶牛死亡,但是发生子宫感染的奶牛其生产性能会受到很大影响。另外,子宫发生感染还会降低产奶量,并且对子宫感染的一些治疗措施还会对牛奶产生污染。因为感染的非特异性,所以子宫感染很难预防;注意加强卫生设施以及围产期的卫生,特别是在助产过程中的卫生,才可能是最好的预防方法。异常免疫功能导致奶牛发生子宫感染的现象,说明通过对免疫功能的调节来预防和治疗围产期奶牛子宫感染是有潜力的。

The Postpartum Cow Uterine Infection and Immune Function

Nonspecific uterine infections reduce the reproductive efficiency of cows and the profit potential of dairy farms.Fortunately,most cows do not develop severe uterine infections.The term uterine infection indicates that the uterus is contaminated with pathogenic organisms.Actinomyces pyogenes,either alone or with other bacteria,is often associated with uterine infections.When A.pyogenes was isolated from uterine fluids after 21d postpartum,cows developed severe endometritis and were infertile at first service.However,the exact causes of uterine infections are unknown but are associated with several factors.Cows with dystocia,retained placenta,twins or stillbirths,and various metabolic disorders are more likely to develop metritis than are other cows.Aberrant immune function before and after calving seems to predispose cows to severe uterine infections.Few cows die from uterine infections,but cows with uterine infections are more likely to be culled for poor reproductive performance.Also,uterine infections can reduce milk production,and some treatments contaminate milk.Because they are nonspecific,uterine infections are difficult to prevent;attention to sanitation and periparturient hygiene,especially during assisted calving,may be the best defense.Evidence that aberrant immune function predisposes cows to uterine infections indicates that methods for regulating immune function in periparturient cows have the potential for preventing or treating uterine infections.