Hormonal treatments for increasing the oocyte and embryo production in an OPU-IVP system.

The objective was to enhance the inherent developmental ability of bovine oocytes retrieved by ultrasound-guided transvaginal aspiration. Various hormonal regimes were utilized to produce partially matured oocytes in vivo, in order to improve embryo development following IVF. In the first experiment, a two-by-two factorial design was used with FSH (multiple versus single dose) and im administration of LH (yes versus no) 6h prior to OPU. In all protocols (which lasted for nine consecutive weeks), ovarian stimulation was performed in the presence of a CIDR. One FSH administration was adequate for ovarian stimulation (9.33+/-0.7 and 10.14+/-0.7 follicles per cow per OPU session); however, multiple injections increased (P<0.05) follicular response (12.97+/-0.7 and 13.97+/-0.7). In the second experiment, a two-by-two factorial design was used to compare the effects, during ovarian stimulation, of the presence or absence of CIDR, and iv treatment with LH 6h prior to OPU (yes versus no), on oocyte competence (judged by blastocyst development rates following IVF). Presence of CIDR during superstimulation had no effect on the follicular response. Administration of LH 6h prior to OPU increased (P<0.05) the oocytes of higher morphological grades, and in the absence of a CIDR, improved (P<0.05) blastocyst development rate. Treatment with LH, 6h prior to OPU without the use of CIDR during ovarian stimulation, resulted in 2.89+/-0.4 blastocysts per cow per OPU session as compared to 1.56+/-0.4, 1.56+/-0.4 and 1.33+/-0.4 for all other groups. In conclusion, compared to single administration, multiple FSH administration increased (P<0.05) available follicles for aspiration. Moreover, when ovarian stimulation in the absence of CIDR was followed by administration of LH 6h prior to OPU, it increased (P<0.05) the number of blastocysts per OPU session.

Comparison of different transvaginal ovum pick-up protocols to optimise oocyte retrieval and embryo production over a 10-week period in cows.

The objective was to develop a simple and effective ovum pick-up (OPU) protocol for cows, optimised for oocyte harvest and subsequent in vitro embryo production (IVP). Five protocols differing in collection frequency, dominant follicle removal (DFR) and FSH stimulation were tested on groups of three cows each, over an interval of 10 consecutive weeks. Performance was evaluated on per OPU session, per week and pooled (3 cowsx10weeks) basis. Among the non-stimulated groups, on a per cow per session basis, once- or twice-weekly OPU had no effect on the mean (+/- S.E.M.) number of follicles aspirated, oocytes retrieved and blastocysts produced (0.6+/-0.8 and 0.7 +/- 0.7, respectively). However, DFR 72 h prior to OPU almost doubled blastocyst production (1.2 +/- 1.3). In stimulated groups, FSH treatment (80 mg IM and 120 mg SC) was given once weekly prior to OPU. Treatment with FSH, followed by twice-weekly OPU, failed to show any synergistic effect of FSH and increased aspiration frequency. When FSH was given 36 h after DFR, followed by OPU 48 h later, more (P < 0.05) follicles (16.0 +/- 5.0), oocytes (10.6 +/- 4.5) and embryos (2.1 +/- 1.2) were obtained during each session, but not on a weekly basis. Pooled results over 10 weeks showed an overall improved performance for the treatment groups with twice-weekly OPU sessions, due to double the number of OPU sessions performed. However, the protocol that consisted of DFR, FSH treatment and a subsequent single OPU per week, was the most productive and cost-effective, with potential commercial appeal.

Agro-economic impact of cattle cloning.

The purpose of this paper is to review the economic and social implications of cloned cattle, their products, and their offspring as related to production agriculture. Cloning technology in cattle has several applications outside of traditional production agriculture. These applications can include bio-medical applications, such as the production of pharmaceuticals in the blood or milk of transgenic cattle. Cloning may also be useful in the production of research models. These models may or may not include genetic modifications. Uses in agriculture include many applications of the technology. These include making genetic copies of elite seed stock and prize winning show cattle. Other purposes may range from "insurance" to making copies of cattle that have sentimental value, similar to cloning of pets. Increased selection opportunities available with cloning may provide for improvement in genetic gain. The ultimate goal of cloning has often been envisioned as a system for producing quantity and uniformity of the perfect dairy cow. However, only if heritability were 100%, would clone mates have complete uniformity. Changes in the environment may have significant impact on the productivity and longevity of the resulting clones. Changes in consumer preferences and economic input costs may all change the definition of the perfect cow. The cost of producing such animals via cloning must be economically feasible to meet the intended applications. Present inefficiencies limit cloning opportunities to highly valued animals. Improvements are necessary to move the applications toward commercial application. Cloning has additional obstacles to conquer. Social and regulatory acceptance of cloning is paramount to its utilization in production agriculture. Regulatory acceptance will need to address the animal, its products, and its offspring. In summary, cloning is another tool in the animal biotechnology toolbox, which includes artificial insemination, sexing of semen, embryo sexing and in vitro fertilization. While it will not replace any of the above mentioned, its degree of utilization will depend on both improvement in efficiency as well as social and regulatory acceptance.

Commercialization of animal biotechnology.

Commercialization of animal biotechnology is a wide-ranging topic for discussion. In this paper, we will attempt to review embryo transfer (ET) and related technologies that relate to food-producing mammals. A brief review of the history of advances in biotechnology will provide a glimpse to present and future applications. Commercialization of animal biotechnology is presently taking two pathways. The first application involves the use of animals for biomedical purposes. Very few companies have developed all of the core competencies and intellectual properties to complete the bridge from lab bench to product. The second pathway of application is for the production of animals used for food. Artificial insemination (AI), embryo transfer, in vitro fertilization (IVF), cloning, transgenics, and genomics all are components of the toolbox for present and future applications. Individually, these are powerful tools capable of providing significant improvements in productivity. Combinations of these technologies coupled with information systems and data analysis, will provide even more significant change in the next decade. Any strategies for the commercial application of animal biotechnology must include a careful review of regulatory and social concerns. Careful review of industry infrastructure is also important. Our colleagues in plant biotechnology have helped highlight some of these pitfalls and provide us with a retrospective review. In summary, today we have core competencies that provide a wealth of opportunities for the members of this society, commercial companies, producers, and the general population. Successful commercialization will benefit all of the above stakeholders.

Gritti-Stokes (through-knee) amputation: should it be reintroduced?

BACKGROUND: When there is doubt about perfusion in the distal part of the leg and around the ankle, an above-knee amputation (AKA) site has been the most commonly selected to assure primary wound healing. METHODS: The Gritti-Stokes amputation (GSA), a modified through-knee amputation, seems to have value for selected patients, according to a literature review and our success in a small group of patients. We have investigated the proportion of patients who have had AKA and who might have been suitable candidates for GSA. RESULTS: In a retrospective study of 66 patients who had had AKA, at least one third could have been considered for a GSA and might have benefitted from this procedure. This suggests that some consideration should be given to the reintroduction of the Gritti-Stokes operation. CONCLUSION: Our expectation is that patients so treated could achieve a high proportion of primary wound healing, an end-bearing stump, and more rapid rehabilitation than found in patients undergoing the classic AKA.

Transgenic production from in vivo-derived embryos: effect on calf birth weight and sex ratio.

We examined transgenic-cattle production by DNA microinjection into 1-, 2-, and 4-cell embryos, analyzing the impact on calf size and subsequent viability. Embryos were either collected at an abattoir by flushing oviducts from superovulated and artificially inseminated cows (in vivo-derived) or obtained by in vitro maturation and in vitro fertilization of oocytes aspirated from excised ovaries (in vitro-derived). A human serum albumin (hSA) milk-expression DNA construct was microinjected, either in one of the visible pronuclei of in vitro- and in vivo-derived 1-cell embryos or in the nuclei of two blastomeres of 2- and 4-cell in vivo-derived embryos. Microinjection-induced mortality (lysis and developmental block) was equivalent ( approximately 40%) for all microinjected embryos. Embryos were co-cultured with BRL cells in B-2 medium containing 10% fetal calf serum (FSC). Overall, embryo development to morulae/blastocysts was significantly greater for in vivo-derived ova (15.5%) than for in vitro-derived oocytes (9.3%). All morulae and blastocysts were transferred to synchronized recipient females on Days 6-8 post-fertilization. A total of 189 calves were delivered. Birth weights were significantly greater for calves generated from in vitro-derived oocytes compared with those generated from in vivo-derived oocytes. One transgenic bull calf was obtained from the microinjection of a 2-cell embryo. Fluorescence in situ hybridization (FISH) analysis of lymphocytes detected one transgenic integration site in all cells. Transmission frequency of the hSA transgene in embryos obtained through IVM/IVF/IVC utilizing the semen of the transgenic calf confirmed that it was not mosaic.

What would make us stay in West Virginia?: perspectives of the state's medical students.

In summer 1994, a questionnaire was sent to all of the 822 allopathic and osteopathic medical students in West Virginia. They were asked if they planned to practice primary care in the state, and to rate the importance of financial, lifestyle, and educational factors that may impel them to practice in rural areas. The response rate was 51.8%. The results indicated that 70.2% of the students were unsure about their career plans, but they were considering staying in the state as primary caregivers. Financial factors such as tuition waivers, loan repayment programs, the improvement of Medicaid and Medicare reimbursement, and the elimination of the 2% healthcare provider tax were the most important incentives that students stated would influence them to remain in the state. Responses also indicated that lifestyle factors such as the quality of schools for children and having backup may increase participation in rural care. Educational factors were not found to be important reasons affecting students' decisions to practice in rural areas, and many students stated they were unhappy with the current mandatory rotations in rural care. Out-of-state students displayed great interest in both staying in West Virginia and in becoming primary care physicians. Few differences were found between students depending on what school they attended or their gender.