Early Embryonic Development In Cattle Research Articles

Stimulation of early embryonic development in cattle by coculture with surfactant.

Our purpose was to determine the efficacy of Surfacten, a bovine pulmonary surfactant, on the maturation of in vitro bovine ova. We used Surfacten as a supplement to the coculture media both at the onset of coculture and after cleavage in bovine ova had been determined. The controls received no Surfacten. The maturation rate in bovine embryos to the blastocyst stage statistically improved (P < 0.05) in the series in which Surfacten was added to the media at the onset of coculture, compared with the controls and the series in which Surfacten was added after cleavage had been determined. Surfacten, a commercially available surfactant which is a naturally occurring phospholipid that dramatically increases in the cervical mucus and the ampullaris of the oviduct at or near the time of ovulation, improves the maturation of bovine embryos in vitro by making the coculture medium approach the conditions found in the oviducts.

Instructing the animal physiology graduate student in human assisted reproductive technology2

Animal physiology graduate students provide an excellent personnel resource for laboratories performing human assisted reproductive technology (ART) procedures. However, the basic training of these students falls short of what is required for this highly specialized field. We designed a course to enhance their education in this area via classroom and hands-on laboratory instruction in a hospital and university setting. Topics covered in the course included in vitro maturation, in vitro fertilization, embryo culture, embryo transfer, quality control, quality assurance, micromanipulation, and cryopreservation. These techniques were applied to a group project to evaluate the influence of spermatozoal quality and quantity on early embryonic development in cattle and humans. Student grades were based on 1) oral and written examinations; 2) demonstrated competency in laboratory techniques; 3) presentation of class project data at a state academy of science meeting; and 4) initiative, determination, and interest in the coursework. Three aspects of the course stood out as very positive. First, the team approach to accomplishing a class project was new to some of the graduate students. Second, a bond was formed between hospital- and university-based faculty that did and will continue to foster unique teaching and research opportunities between the two groups. Third, the opportunity for students to present research data in a formal setting was very rewarding. This course made the students keenly aware of the many aspects of ART and provided them with specialized skills that should make them more marketable in the field of reproductive technology.

Influence of serum and hormones on bovine oocyte maturation and fertilization in vitro

Three approaches were investigated for improvement of in vitro maturation (IVM), in vitro fertilization (IVF), and early embryonic development in cattle. These were: 1) Selection of oocytes, 2) medium supplementation with fetal calf serum (FCS) and cow sera (D0, D1, D10, and D20 to correspond with estrus, metestrus, diestrus, and proestrus, respectively), and 3) addition of follicle-stimulating hormone (FSH), luteinizing hormone (LH), and estradiol-17 beta (E2) during maturation. Greater proportions (percentage) of oocytes initially selected for their compact cumulus cells completed IVM and IVF when compared to unselected oocytes (P less than .05). Proportions (percentage) of selected oocytes that matured and cleaved after in vitro insemination according to serum type used for IVM were: FCS: 110/175 (62.9%) and 37/110 (33.6%) and D0: 130/145 (89.7%) and 52/130 (40.0%); D1 127/130 (97.7%) and 41/127 (32.3%); D10 95/98 (96.9%) and 35/95 (36.8%); D20:113/116 (97.4%) and 49/113 (43.4%). A higher proportion (P less than .05) of embryos resulting from the D20 group reached four- and eight-cell stages. In FCS-supplemented maturation media with no hormones added during maturation (control), results of IVM and IVF were 157/265 (59.2%) and 39/157 (24.8%), respectively. With E2 (1 microgram/ml) and FSH (5 micrograms/ml), comparable results were 189/215 (87.9%) and 71/189 (37.6%); with E2 (1 microgram/ml) plus LH (10 micrograms/ml), 280/327 (85.6%) and 111/280 (39.6%). Added hormones improved IVM results (P less than .05) and, when FSH or LH was added with E2, in vitro development to four- and eight-cell stages was markedly enhanced (P less than .05). Selection of oocytes, D20 serum, and added E2 and FSH or LH for IVM improved in vitro development of bovine embryos after IVF.