If foetal membranes are not expelled within 24 hours after giving birth they are classed as retained. They are normally expelled within 3 to 8 hrs after birth but may be retained for up to two weeks. Retained placenta is rare in beef cattle, may affect 5-15% of dairy cows, and is more common following early or abnormal parturition or abortion. Most cases require no treatment, but complications such as metritis and toxaemia may become life-threatening.
Presence of visible membranes at the vulva are an obvious sign but cows may have retained placenta without any external sign. Diagnosis generally depends on physical examination including rectal and vaginal examination.
Manual removal is no longer recommended because of the risk of trauma, haemorrhage and subsequent infection of the uterus. Removing the exteriorised membranes by trimming under slight tension is generally preferred.
Antibiotic pessaries inserted into the uterus are ineffective at reducing infection or preventing metritis and may delay separation which relies on bacterial action.
Animals with retained membranes that show systemic signs of illness associated with metritis, should be treated with systemic antibiotics such as procaine penicillin, oxytetracycline or trimethoprim sulpha.
Specific preventative measures are not warranted because of the retained placenta is likely to be uncommon in the export process.