Detection of embryonic death and observations on resorption and subsequent fertility in the ewe

Abstract

Embryos were killed by injection of colchicine into the uterus of ewes 20, 25 and 30 days pregnant. The ewes returned to service 15.0 ± 3.5 days later (range 6.0 to 32.0 days). The presence of debris and additional fluid on vaginal swabs indicated loss of an embryo, but the interval from induced embryo death until the next oestrus was too variable for accurate determination of the time of embryo death. Much of the embryo debris passed into the vagina within the first four days after embryo death. The bacterial, leucocyte and polymorphonucleocyte populations increased in vaginal smears taken from ewes resorbing an embryo, in marked contrast with smears taken from pregnant and non-pregnant ewes. Artificial insemination of normal oestrous ewes and ewes in oestrus subsequent to embryo death, showed that fertility at the oestrus following embryo death is significantly reduced.