Niamh Lewis

University of Liverpool | UoL · Institute of Ageing & Chronic Disease

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 embryo...

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). Expos...

Horses are one of the few species, beside humans, in which assisted reproductive technology has important clinical applications. Furthermore, the horse can serve as a valuable model for the study of comparative reproductive biology. Here we present the first comprehensive characterisation of energy metabolism and mitochondrial efficiency in equine...

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 m...

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...

Background: 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 t...

Production of equine embryos using intracytoplasmic sperm injection (ICSI) is rapidly gaining interest in the horse industry. Due to increasing client demand, equine practitioners with limited experience in embryology are attempting to set up clinical ICSI programs, with little success. We report here studies performed with the purpose of establish...

Niamh Lewis BVM&S Dip ACT Dip ECAR MRCVS, explains the technology behind ICSI – the most complex of equine in vitro fertilisation procedures

Production of equine embryos in vitro is gaining popularity, and many differences exist in composition of in vitro maturation (IVM) media. Metabolism of the cumulus-oocyte complex (COC) is essentially unknown in the horse. Here, we describe preliminary data on carbohydrate metabolism of the equine COC during IVM. COC, collected by scraping of the g...

Insemination with frozen-thawed (FZ) semen has been associated with an increased incidence of post-breeding intrauterine fluid (IUF) accumulation and decreased pregnancy rates per cycle (PR) compared with fresh (F) and chilled (CH) semen. This retrospective study was undertaken to determine the PR and incidence of post-breeding IUF associated with...