Abstract

Retained placentas were one of the primary reasons for clinical admission in three large, non-human primate breeding colonies. Over a five-year span, retained placenta was seen in 4.2% of all cynomolgus macaque (Macaca fascicularis) births, 1.1% of all rhesus macaque (Macaca mulatta) births, and 5.2% of all baboon (Papio sp.) births. Some apparent risk factors for the occurrence of a retained placenta include a stillbirth or prior cesarean section. Of those animals with retained placentas, the association with stillbirths varied, with 72% in cynomolgus, 100% in rhesus, and 47.3% in baboons. Prior cesarean section(s) was not a factor in the two macaque colonies but was present in 39.1% of baboons with retained placentas. In all colonies, the average age of animals with a retained placenta fell within the prime breeding age range for the species, with both younger and older also being affected.

Treatment of a retained placenta can be challenging in non-human primates due to limited access to the individuals. Successful treatment regimens within the colonies varied greatly. Treatment was tailored to each animal based on their overall health, duration of retention, and history. Treatment modalities ranged from observation to combinations of manual uterine massage, fluid therapy, pain management, oxytocin injections, antibiotics, vitamin B12 and B-complex injections, iron injections, and curettage and flushing of the uterus. Complications from a retained placenta rarely caused serious long-term health problems.