Proceedings of the 5th International Symposium on EQUINE ...

Equine Embryo TransferEMBRYO RECOVERY RATES IN MARES WITHECHOGENIC PREOVULATORY FOLLICLESP. M. McCue, D. K. Vanderwall and E. L. SquiresEquine Reproduction Laboratory, Colorado State University, Fort Collins, Colorado 80523, USAINTRODUCTIONEchogenic particles may be noted in <strong>the</strong> follicularfluid <strong>of</strong> dominant follicles prior to ovulation insome mares. The goals <strong>of</strong> this study were todetermine <strong>the</strong> incidence <strong>of</strong> preovulatory folliclescontaining echogenic follicular fluid and compareembryo recovery rates following ovulation<strong>of</strong> echogenic or non-echogenic follicles.Reproductive records <strong>of</strong> 721 mares examined bytransrectal ultrasonography prior to breeding overa total <strong>of</strong> 1,694 oestrous cycles were reviewed.Embryo recovery data were recorded for 34 maresthat ovulated a single non-echogenic follicle or asingle echogenic follicle during oestrous cycleswithin <strong>the</strong> same breeding season. Non-echogenicand echogenic preovulatory follicles were noted in93.8% and 6.2% <strong>of</strong> <strong>the</strong> cycles, respectively.Embryo recovery rate per flush was significantlyhigher (P