Retained Placenta: Causes and Treatments

Several trials of interventions after calving have attempted to reduce the incidence of retained placenta. Oxytocin has long been advocated to expel the placenta after delivery. There are other advantages to the use of oxytocin after calving but it does not reduce the incidence of retained placenta. Oxytocin is already being secreted by normal cows at parturition and it helps contract the uterus and expel a placenta that is fully detached. The contraction of the uterus helps control bleeding from the various sites that may have been traumatized during delivery. If the placenta is not detached from the caruncles oxytocin will not hasten its passage (12). Low rates of retained placenta during an experiment that required induction of calving was reported with the use of 10 mg of dinoprost tromethamine (Lutalyse, Pharmacia and Upjohn Co.) given within a few hours of calving (8). I conducted a trial in a client herd with 400 calvings to evaluate this as a prevention. There was no difference between the prostaglandin treatment and the placebo. A follow up trial was conducted with induced calvings and either dinoprost or cloprostenol and no reduction in the incidence of retained placenta was observed (6). The use of prostaglandins at parturition has yielded mixed results. The use of Lutalyse (Pharmacia & Upjohn) at calving does not reduce the incidence of retained placenta (14). However, the use of a longer acting prostaglandin, fenprostalene - no longer marketed in the USA, did result in a shorter duration of placental retention and a reduction in subsequent metritis (10). An experimental injection of collagenase into the placental end of the umbilical artery has been shown to facilitate separation of the placenta from the uterus (4). This mode of therapy is specific and appropriate for releasing the placenta from the uterus but has not evolved into a practical treatment.

Many medications have been placed into the uterus of cows with retained placenta. Veterinarians have sometimes devised very detailed protocols requiring sequential placement of antibiotics and other chemicals into the uterus on various days after calving. To date there is no data supporting the beneficial effects of intrauterine therapy for retained placenta. Some cows do not become sick, do not stink, and require no therapy whatsoever. Most cows do become systemically ill and require antibiotic and adjunctive therapy. The aim of therapy is both to minimize illness at the start of lactation so feed intake and milk production will get off to a good start and to reduce the reproductive inefficiency at the start of the breeding period.

I work with many large dairies where therapy of routine problems is administered by the herd staff under my guidance. To insure consistency in treatment programs, protocols have been developed to cover most common conditions including retained placenta and metritis. Fresh cow monitoring is a part of the daily routine on these dairies. Whether your dairy is large or small, the principles of systematic approaches to health problems will help insure that the right cows are treated and with logical interventions. The following is a portion of a typical herd protocol.