Review on Retention of Placenta in Dairy Cows and it is Economic and Reproductive Impacts

Fetal membranes or what is known as “placenta” is an essential organ for prenatal transfer of nutrients and oxygen from the dam to the fetus. The normal separation of fetal membranes consists of complex hormonal process that starts before parturition in cows, which drops within short time after birth. It normally drops within short time post partum. If the placenta is not expelled within certain time (12 h post calving and 3 h post foaling), it is defined as being retained placenta (RP). Its a condition where all or part of the placenta or membranes are left behind in the uterus during the third stage of labour. Retained placenta creates a number of problems following pulling of microorganisms into the uterus causing its inflammation, decreased milk yield, longer calving intervals, reduction of fertility, longer calving interval, and reduce conception rate. RP causes great economic losses, mainly due to decreased milk yield and loss due to infertility. The number of risk factors of retained placenta includes stillbirth, dystocia, abortion, twin, fetotomy, induction of parturition, cesarean section, shortened gestation, managemental system, heridetary, hormonal, infectious disease and maternal immune system. Since there are many causative agents of retained placenta, the treatments which are commonly used for the retention of fetal membranes do not show the significant effects. Therefore, Basically, we have to avoid the occurrence of dystocia through genetic selection of dam and sire having minimal probability for RP, proper prepartum nutritional status and exercise. Special care should be paid for nutrition and vitamin supplementation, especially during the dry period. It could be concluded that RP is an important problem which causes great economic losses and leave the animal subfertile even after treatment and recovery. So, it is recommended to control the condition rather than to treat it. Keywords: Cows, Retention of placenta, Risk factors, Placental detachment, Dystocia