Equine ART and antral follicle count: Can we deepen our understanding to improve outcomes?

Assisted reproductive technologies (ARTs) are performed worldwide in the equine industry to produce genetically valuable foals. Among them, ovum pick up (OPU) combined with intra-cytoplasmic sperm injection (ICSI) can now be more efficient than embryo transfer (ET) under optimal conditions. However, OPU is not a benign procedure for the mare and the process is costly.

Equine produced blastocysts: relationship of embryo morphology, stage and speed of development to foaling rate.

Context: Information on factors associated with developmental competence of equine in vitro -produced (IVP) blastocysts is lacking.

Aims: To determine the relationships of stage, grade, day of development, and specific morphological parameters of equine IVP blastocysts, to pregnancy and foaling rates.

Methods: Photomicrographs of 316 IVP embryos with known pregnancy outcomes were scrutinised individually by four observers.

Glucose concentration during equine in vitro maturation alters mitochondrial function.

The use of in vitro embryo production in the horse is increasing in clinical and research settings; however, protocols are yet to be optimised. Notably, the two most commonly used base media for in vitro maturation (IVM) supply glucose at markedly different concentrations: physiological (5.6 mM, M199) or supraphysiological (17 mM, DMEM/F-12).

Application of extracellular flux analysis for determining mitochondrial function in mammalian oocytes and early embryos.

Mitochondria provide the major source of ATP for mammalian oocyte maturation and early embryo development. Oxygen Consumption Rate (OCR) is an established measure of mitochondrial function. OCR by mammalian oocytes and embryos has generally been restricted to overall uptake and detailed understanding of the components of OCR dedicated to specific molecular events remains lacking.

Morphokinetics of early equine embryo development in vitro using time-lapse imaging, and use in selecting blastocysts for transfer.

The use of time-lapse imaging (TLI) in the evaluation of morphokinetics associated with invitro developmental competence is well described for human, cattle and pig embryos. It is generally accepted that embryos that complete early cleavage sooner are more likely to form blastocysts and that timing of later events, such as blastocyst formation and expansion, are predictive of implantation potential and euploid status. In the horse, morphokinetics as a predictor of developmental competence has received little attention.