“…However, administration beyond the normal lifespan of corpora lutea suppresses fertility of the subsequent estrus (DeBois and Bierschwal, 1970;Beal et al, 1988;Anderson and Day, 1994). Therefore, some researchers have taken the approach of administering MGA for about 14 days followed by the administration of the luteolysin prostaglandin F,, (PGF,) about 17 d later so that estrus can be synchronized with normal fertility (Brown et al, 1988;Jaeger et al, 1992). Synchronized pregnancy rates (6-day) to this procedure have been reported to be about 49 to 57% and are similar to pregnancy rates in females that had been bred at non-synchronized estrus.…”