BOVINE RETAINED PLACENTA - ETIOLOGY, PATHOGENESIS AND ECONOMIC-LOSS

The literature on the effects and causes of retained placenta in the c ow is reviewed. On a herd basis the condition can adversely affect mil k yield and fertility, but on an individual cow basis the effects are unpredictable, The aetiology of retained placenta has been extensively studied and many causal factors have been implicated, but little is k nown of how many of them cause the condition. iis a result its prevent ion and prediction is uncertain, primarily because of the lack of know ledge of the normal process of placental release. Vascular changes and uterine contractions play a role in placental release, but current op inion suggests that the primary cause of retained placenta is the rete ntion of the fete-maternal union. Release only occurs after a process of maturation, which involves hormonal and structural changes. The fac tors which are thought to influence these changes, and thus cause the condition, are discussed.