Analysis of physical traits, clinical parameters, and energy metabolism of in vivo- and in vitro-derived Flemish newborn calves during the first day of life.

Studies investigating physiological deviations from normality in newborn calves derived from in vitro fertilization procedures remain important for the understanding of factors that reduce calf survival after birth. The aim of this study was to investigate parameters affecting health and welfare of newborn Flemish calves derived from in vitro embryo production (IVP) in the first hours of life in comparison to in vivo-derived calves. Physical traits of newborn calves and fetal membranes (FM) were recorded soon after birth.

and embryo production efficiency in Flemish and Holstein donor females.

The aim of this study was to compare embryo production efficiency in Flemish and Holstein donor females using ovum pick-up and fertilization (OPU-IVF) or production (superovulation; SOV) procedures. The study was conducted using a split-plot design, with eight Flemish and eight Holstein non-lactating cycling females. Females were subjected to ten weekly OPU/IVF sessions and/or two SOV/embryo collections sessions at a 63-day interval, for a total of 160 OPU-IVF and 32 SOV sessions.

Effects of fusion-activation interval and embryo aggregation on in vitro and in vivo development of bovine cloned embryos.

Nuclear reprogramming in somatic cell cloning is one of the key factors for proper development, with variations in the protocol appearing to improve cloning efficiency. This study aimed to determine the effects of two fusion-activation intervals and the aggregation of bovine cloned embryos on subsequent in vitro and in vivo development. Zygotes produced by handmade cloning were exposed to two fusion-activation intervals (2 h or 4 h), and then cultured in microwells either individually (1 × 100%) or after aggregation of two structures (2 × 100%).

Impact of cumulative gain in expertise on the efficiency of handmade cloning in cattle.

The aim of this study was to determine the effects of the cumulative gain in expertise in carrying out handmade cloning (HMC) procedures on embryo yield and pregnancy outcome in cattle. Results from in vitro and in vivo embryo development after HMC during three periods of 7 months, separated by 3-month intervals, were compiled and designated as P1, P2 and P3. Blastocyst yield, morphological quality and stage of development, and pregnancy per embryo transfer (ET) on Day 30 of gestation were compared.

Morphometric developmental pattern of bovine handmade cloned concepti in late pregnancy.

Cloning procedures often interfere with conceptus growth and life ex utero, in a set of symptoms known as abnormal offspring syndrome (AOS). The aim of the present study was to compare the developmental pattern of in vivo-derived (IVD), IVF-derived and handmade cloning-derived (NT-HMC) Day 225 bovine concepti using established procedures. Pregnancy diagnosis was performed on Day 30 following blastocyst transfer on Day 7.

Developmental Outcome and Related Abnormalities in Goats: Comparison Between Somatic Cell Nuclear Transfer- and In Vivo-Derived Concepti During Pregnancy Through Term.

Cloning by somatic cell nuclear transfer (SCNT) is characterized by low efficiency and the occurrence of developmental abnormalities, which are rather poorly studied phenomena in goats. This study aimed at comparing overall SCNT efficiency in goats by using in vitro-matured (IVM) or in vivo-matured oocytes and fibroblast donor cells (mock transfected, transgenic, or wild type), also characterizing symptoms of the Abnormal Offspring Syndrome (AOS) in development, comparing results with pregnancies produced by artificial insemination (AI) and in vivo-derived (IVD) embryos. The SCNT group had lower pregnancy rate (18.

In vitro development of cloned bovine embryos produced by handmade cloning using somatic cells from distinct levels of cell culture confluence.

The relationship between the level of cell confluence near the plateau phase of growth and blastocyst yield following somatic cell cloning is not well understood. We examined the effect of distinct cell culture confluence levels on in vitro development of cloned bovine embryos. In vitro-matured bovine oocytes were manually bisected and selected by DNA staining.

Developmental potential of bovine hand-made clone embryos reconstructed by aggregation or fusion with distinct cytoplasmic volumes.

Animal cloning has been associated with developmental abnormalities, with the level of heteroplasmy caused by the procedure being one of its potential limiting factors. The aim of this study was to determine the effect of the fusion of hemicytoplasts or aggregation of hemiembryos, varying the final cytoplasmic volume, on development and cell density of embryos produced by hand-made cloning (HMC), parthenogenesis or by in vitro fertilization (IVF). One or two enucleated hemicytoplasts were paired and fused with one skin somatic cell.

Calves born after direct transfer of vitrified bovine in vitro-produced blastocysts derived from vitrified immature oocytes.

Vitrification has been the method of choice for the cryopreservation of bovine oocytes, as rapid cooling decreases chilling sensitivity. The aim of this study was to determine the in vitro and in vivo survival and the viability of immature oocytes vitrified using super-cooled liquid nitrogen. Immature oocytes were randomly allocated to three groups: (i) non-vitrified control group, (ii) vitrified in normal (-196 degrees C) liquid nitrogen (LN(2)) and (iii) vitrified in super-cooled LN(2) (< or =-200 degrees C).

In-straw cryoprotectant dilution of IVP bovine blastocysts vitrified in hand-pulled glass micropipettes.

The aim of this study was to determine the influence of two ethylene glycol-based vitrification solutions on in vitro and in vivo survival after in-straw cryoprotectant dilution of vitrified in vitro-produced bovine embryos. Day-7 expanded blastocysts were selected according to diameter (> or = 180 microm) and osmotic characteristics and randomly assigned to one of three groups (i) VSa: vitrification in 40% EG+17.1% SUC+0.

Current status of sperm cryopreservation: why isn't it better?

Cryopreservation extends the availability of sperm for fertilization; however, the fertilizing potential of the frozen-thawed sperm is compromised because of alterations in the structure and physiology of the sperm cell. These alterations, characteristics of sperm capacitation, are present in the motile population and decrease sperm life-span, ability to interact with female tract, and fertilizing ability. The etiology of such alterations may represent a combination of factors, such as inherited fragility of the sperm cell to withstand the cryopreservation process and the semen dilution.

Splitting and biopsy for bovine embryo sexing under field conditions.

Improvements on embryo micromanipulation techniques led to the use of embryo bisection technology in commercial embryo transfer programs, and made possible the direct genetic analysis of preimplantation bovine embryos by biopsy. For example, aspiration and microsection, allow bovine embryos sexing by detection of male-specific Y-chromosome in a sample of embryonic cells. We report on the application of the methodologies of splitting and biopsy of bovine embryos in field conditions, and on the results of embryo sex determination by the polymerase chain reaction (PCR).