-
[show abstract]
[hide abstract]
ABSTRACT: Eleven mares were induced to ovulate by treatment with 3,000 iu hCG and subsequently inseminated with frozen-thawed semen. The time of ovulation was determined by transrectal ultrasonography of the ovaries performed every 4 h. At different times after ovulation ova were collected from oviducts removed by surgery through a flank incision under general anaesthesia. The presumed fertilised ova were cultured for 20 min in a medium containing [3H]uridine, fixed, embedded in Epon, semithin-sectioned and processed for autoradiography. Selected semithin sections were re-embedded and processed for transmission electron microscopy. Spherical, paternal and maternal pronuclei were observed within 12 h after ovulation, and by 19 h the pronuclei had migrated to close apposition. The 2-cell stage was seen within 34 h and a major activation of RNA synthesis was detected at 64 h after ovulation in 4 blastomeres of a 6-cell embryo, suggesting maternal-embryonic transition apparently occurs at the 4th cell cycle.
Equine Veterinary Journal 06/2010; 25(S15):79 - 83. · 1.46 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: ContentsThe oocyte growth phase includes development of organelles and inclusions as well as a period of oocyte transcription. Oocyte transcription including nucleolar function (rRNA-synthesis) is activated in the secondary follicle and is maintained up to an oocyte diameter of about 110 μm in the 3 mm tertiary follicle. At a diameter of 100 to 110 μm, the oocyte gradually achieves the competence to undergo meiotic maturation and sustain embryonic development. In the dominant follicle the oocyte undergoes further ultrastructural modifications through a process that we refer to as «Capacitation». The final oocyte maturation up to metaphase II after LH stimulation of the ovulatory follicle is the culmination of the previous processes and equips the oocyte with the cell biological apparatus specialized for fertilization and initial embryonic development.
Reproduction in Domestic Animals 10/2008; 34(5):447 - 454. · 1.36 Impact Factor
-
Reproduction in Domestic Animals 10/2007; 28(3):164 - 169. · 1.36 Impact Factor
-
Reproduction in Domestic Animals 10/2007; 33(5):331 - 342. · 1.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Contents: The present study was undertaken to examine if bovine oocytes matured either in vivo (Experiment I) or in vitro (Experiment II) and fertilized by frozen-thawed spermatozoa in vitro could produce normal calves. In experiment I two one-cell ova were transferred to the oviducts (2 × 2) of a synchronized, final recipient which ultimately became pregnant and delivered a normal bull calf after 275 days of gestation. In experiment II 54 one-cell ova were transferred to the oviduct of an intermediate recipient from which 15 blastocysts were recovered by non-surgical flushing of the uterus 6 days later. Subsequent transfer of 2 blastocysts to the final recipient by a non-surgical technique resulted in pregnancy and birth of a normal heifer calf after 281 days of gestation. The present study confirms that calves can be born from in vitro fertilization of in vivo and in vitro matured oocytes and demonstrates for the first time that calves can be born after non-surgical transfer of bovine oocytes both matured and fertilized in-vitro and incubated in cattle oviducts.Inhalt: Klbergeburten nach In-vitro-Befruchtung von OozytenIn dieser Untersuchung wurde geprüft, ob Rinderooryten nach Reifung in vivo (Exp. 1) oder in vitro (Exp. 2) und anschlieβender In-vitro-Befruchtung sich zu normalen Kl-bern entwickeln können. Im ersten Experiment wurden zwei befruchtete, aber noch nicht geteilte Eier in den Eileiter eines synchronisierten Empfangertieres transferiert, und nach 2 75 Tagen wurde ein normales Bullenkalb geboren. Im zweiten Experiment wurden 54 in vitro gereifte und befruchtete, noch ungeteilte Eier in die Eileiter eines Zwischenempfngers übertragen und nach 6 Tagen durch unchirurgische Uterusspülung 15 Blastozysten wiedergewonnen. Ein nachfolgender unchirurgischer Transfer von 2 Blastozysten in ein Empfngertier führte zur Trchtigkeit und nach 281 Tagen zur Geburt eines normalen Kuhkalbes. Diese Ergebnisse beweisen, daβ durch In-vitro-Befruchtung von in vivo und auch in vitro gereiften Oozyten Klbergeburten möglich sind.
Reproduction in Domestic Animals 10/2007; 24(2):79 - 83. · 1.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: ContentsActivity of the meiosis inducing substance (MIS) and the concentration of steroids in 36 follicular fluids (FF) aspirated from preovulatory follicles at different hours after the LH surge in 12 superovulated cows was investigated. MIS activity was present in 17 (4 7%) of the FFs. The frequency of MIS active follicles varied significantly throughout the preovulatory period, being highest from 11 to 20 hours after the LH surge. No significant differences were found in the intrafollicular concentrations of progesterone and oestradiol between follicles with and without MIS activity. These results confirm previous findings in women and support the notion, that MIS may be an important factor for the regulation of the preovulatory resumption of oocyte meiosis in mammalsInhalt: Meiose induzierende Substanz (MIS) in bovinen provulatorischen FollikelnFollikelflüssigkeit wurde aus provulatorischen Follikeln von 12 superovulierten Kühen zu unterschiedlichen Zeitpunkten nach dem LH-Peak durch Aspiration gewonnen. In der Flüssigkeit uon insgesamt 36 Follikeln wurde die Aktivitt der Meiose induzierenden Substanz (MIS) sowie die Konzentrationen der Steroidhormone Progesteron und Östradiol-17βbestimmt. MIS-Aktivitt wurde in 17 (47%) der Follikelflüssigkeit festgestellt. Die Hufigkeit von MIS-inaktiver Follikelflüssigkeit varüerte signifikant whrend der provulatorischen Periode und war am höchsten zwischen 11 und 20 Stunden nach dem LH-Peak. Zwischen Follikeln mit und ohne MIS-Aktivitt wurden keine signifikanten Unterschiede bei der intrafo llikulren Konzentration an Progesteron und Östradiol-17βgefunden. Diese Ergebnisse besttigen Untersuchungen, die bei Frauen durchgeführt wurden. Sie unterstützen die Hypothese, daβ MIS ein wichtiger Faktor zur Steuerung der provulatorischen Vollendung der Oocyten-Meiose bei Saugern ist.
Reproduction in Domestic Animals 10/2007; 20(4):217 - 221. · 1.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: InhaltFlow-cytometrische DNA-Analyse von Granulosazellen aus superovulierten, bovinen, präovulatorischen FollikelnIn 68 Aspiraten aus präovulatorischen Follikeln von 14 superovulierten Kühen wurde der Anteil der Granulosazellen in der DNA-S-Phase des mitotischen Zyklus (“S-Fraktion”) sowie die Konzentrationen von Progesteron und Östradiol-17β in der Follikelflüssigkeit bestimmt. Zwischen der S-Fraktion und den Konzentrationen der gemessenen Steroidhormone in der Follikelflüssigkeit ergaben sich signifikante Zusammenhänge. Die mitotische Aktivität der Granulosazellen, d.h. die S-Fraktion, blieb bis zu 17 Stunden nach dem präovulatorischen LH-Peak unverändert. Anschließend erfolgte ein signifikanter Abfall bis zur 21.—23. Stunde. Diese Befunde konnen zur Beurteilung der präovulatorischen Periode herangezogen werden. Die S-Fraktion läuft sowohl mit den präovulatorischen follikulären Veränderungen als auch mit den Steroidkonzentrationelz der Follikelflüssigkeit parallel. Sie bietet dadurch eine Möglichkeit, das follikulare Stadium individuell ansprechen zu können. Indirekt ist damit auch eine Aussage über den Reifezustand der Oozyten möglich.
Reproduction in Domestic Animals 10/2007; 22(2):49 - 52. · 1.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Contents: The in vitro developmental potential of blastomeres from early porcine embryos war studied. Two-, 4-, and 8-cell embryos were separated into component blastomeres and replaced into zonae pellucidae in the following configurations (designated by number of blastomeresl original cell stage): half embryos (1/2, 2/4, and 4/8); quarter embryos (1/4 and 2/8); and eighth embryos (1/8). Culture was done in 50 μl droplets under paraffin oil in either Whitten's medium supplemented with 4 mg/ml bovine serum albumin (BSA) and 10% fetal calf serum (FCS) or in the same medium supplemented with porcine oviductal cells. Cultures were observed on a daily baris when the morphology was recorded and at the end of culture (144—168 h after the expected time of ovulation), the embryos were stained with Hoechst 33342 and cell counts made. Generally, no significant differences in developmental rate were found between the two culture system and the data was pooled. Blastocyst formation rate in half embryos was 23%, 28%, and 44% for 1/2, 2/4, and 4/8 embryos, respectively. The respective blastocysts contained an average of 24.3 ± 4.4 and 28.8 ± 2.0 versa 41.2 ± 6.4 cells (p < 0.05 and p < 0.05). Blastocyst formation rate in quarter embryos was 15% and 35% (p < 0.01) for 1/4 and 2/8 embryos, respectively and they possessed an average of 17.0 ± 1.8 and 22.8 ± 1.4 cells (p < 0.02), respectively. Blastocyst formation rate in 1/8 embryos was 9% and the blastocysts averaged 13.0 ± 1.3 cells. Two-,4-, and 8-cell control embryos formed blastocysts at rates of 22%, 85%, and 64%, respectively, and had average cell counts of 45.8 ± 10.8, 69.1 ± 4.0, and 75.4 ± 7.3, respectively. The timing of the initiation of blastocoel formation was similar for reaggregated and control embryos that started culture at the same stage. This along with the cell counts of reaggregated embryos at cavitation, which were proportional to the reduction in cell mars (7.2 ± 0.6, 12.6 ± 1.9, and 25.6 ± 2.8 for quarter, half and control embryos, respectively) supports the assumption that in pigs blastocoel formation occurs independent of the number of cells present.Inhalt: Entwicklung von frühen in vitro kultivierten Schweineblastomeren nach Abtrennung und ReaggregationEs wurde die Entwicklungspotenz von Blastomoren aus frühen Schweineembryonen studiert. Zwei-, Vier- und Achtzell-Embryonen wurden in ihre Blastomerenbestandteile zerlegt und nachfolgendem Schema in Zonae pellucidae zurückverbracht: Halbierte Embryonen (1/2, 2/4, 4/8) Viertelembrynnen (1/4 und 2/8) und Achtelembryonen (1/8). Die Kulturphase erfolgte in 50 μl Tropfen, die mit Parafinöl überschichtet waren. Es wurde Whitten's Medium, entweder mit 4 mg/ml BSA und 10% FCS verwendet oder das Medium mit porcinen Eileitenellen supplementiert. Die Kultur wurde tglich überpüft und die Morphologie beurteilt. Am Ende der Kulturzeit (144–168 Std nach dem berechneten Ovulationszeitpunkt) wurden die Embryonen mit dem Hoechstfarbstoff 33342 gefrbt und die Zellen gezhlt. Signifikante Unterschiede in der Entwicklungsrate zwischen den beiden Medien wurden nicht gefunden und die Daten wurden zusammengefaβt. Die Blastozystenbildungsrate der Embryonenhlften betrug 23% und 44% für 1/2, 2/4 und 4/8 Embryonen. Diese Blastozysten enthielten im Mittel 24,3 ± 4,4 und 28 ± 2,0 gegenüber 41,2 ± 6,4 Zellen (p ≤ 0,05). Die Blastozystenbildungsrate aus Embryoversuchen betrug 1.5% und 35% (p ≤ 0,01) für 1/4 und 2/8 Embryonen. Im Mittel waren 17,0 ± 1,8 und 22,8 ± 1,4 Zellen (p ≤ 0,02) enhvickelt worden. Die Blastozystenbildungsrate in 1/8 Embryonen betrug 9% und durchschnittlich wurden 13,0 ± 1,3 Zellen in den gebildeten Blastozysten nachgewiesen. Zwei-, Vier- und Achtzell-Embryonen der Kontrollgruppe formten zu 22%, 85% und 64% Blastozysten und die mittlere Zellzahl betrug 45,8 ± 10,8, 69,1 ± 4,0 und 75,4 ± 7,3. Der Zeitpunkt der Blastozoelbildung war für reaggregierte und Kontrollembryonen hnlich, wenn sie die Kulturphase im gleichen Enhvicklungsstadium begannen. Diese Tatsache und die vorhandene Zellzahl in reaggregierten Embryonen zum Zeitpunkt der Kavitation, die sich proportional zur Verringerung der Zellzaiilen verhielt (7,2 ± 0,6, 12,6 ± 1,9 und 25,6 ± 2,8 für Viertel-, Halb- und Kontrollembryonen), unterstützt die Annahme, daβ die Blastozoelbildung beim Schwein unabhngig yon der Zellzahl erfolgt.
Reproduction in Domestic Animals 10/2007; 27(5):283 - 289. · 1.36 Impact Factor
-
Reproduction in Domestic Animals 10/2007; 32(6):291 - 296. · 1.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Quantification of embryo respiration is a promising procedure to assess embryonic metabolism and possibly select viable embryos. At the blastocyst stage, ATP is produced by glycolysis and oxidative phosphorylation, processes that require uptake of oxygen and glucose, which is regulated by the expression of GLUT1 and G6PD. The purpose of the present study was to investigate the relationship between respiration rates and relative abundances of G6PD and GLUT1 transcripts in individual bovine blastocysts produced in vitro. Respiration rates of 104 bovine in vitro-produced blastocysts were measured individually using the nanorespirometer technology. Real-time RT-PCR was employed to determine the relative abundance of G6PD and GLUT1 mRNA in individual embryos. The mean respiration rates were similar for male and female blastocysts of the same developmental stage, but the sex ratio was skewed towards males. GLUT1 expression was down-regulated in female versus male embryos. In contrast, a approximately 1.8-fold increase in the expression of G6PD mRNA was observed in female blastocysts when compared to male blastocysts, indicating that dosage compensation for this gene had not yet occurred. Both GLUT1 and G6PD expression levels were affected by morphological quality and stage of development. Expression of GLUT1 and G6PD mRNAs was correlated with respiration rates, indicating that, in metabolically active blastocysts, uptake of oxygen and glucose are jointly increased. These findings suggest that expression of genes for oxidative phosphorylation and glycolysis are both involved in oxygen demanding ATP production.
Theriogenology 08/2007; 68(2):223-36. · 1.96 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Quantification of oxygen consumption by individual preimplantation embryos has the potential to improve embryo selection. This study investigated whether respiration rates of individual embryos are useful indicators of embryo viability. The effect of the Nanorespirometer on embryo viability was also evaluated.
The respiration rates of individual day 7 bovine in vivo- (n=44) and in vitro-produced (n=156) embryos were measured using the Nanorespirometer. In vivo-produced embryos were individually transferred to recipients.
The respiration rates of in vivo-produced embryos increased with increasing morphological quality and stage of development (P < 0.05). Pregnancy rates on days 35 and 60 were 65 and 60%, respectively. The mean respiration rate did not differ significantly between embryos producing and not producing a pregnancy, but the transfer of embryos with respiration rates <0.78 nl/h, between 0.78 and 1.10 nl/h, and >1.10 nl/h resulted in 48, 100 and 25% pregnancy rate, respectively. The mean respiration rate of in vitro-produced embryos was higher than that of in vivo-produced embryos because of differences in the morphological quality and stage of development.
The Nanorespirometer does not adversely influence embryo viability, but the sample size was too small to confirm the significance of the correlation observed between respiration rates and viability.
Human Reproduction 03/2007; 22(2):558-66. · 4.47 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The objective of this study was to investigate (i) the effect of two different ovum pick-up (OPU) schemes (once vs twice weekly aspirations) on oocyte recovery rate, quality and subsequent in vitro embryo development, (ii) the influence of days post-partum on oocyte recovery and (iii) possible differences in OPU results from two different herds. In group A, OPU was performed twice weekly in two Holstein Friesian (HF) and three Danish Red and White (DRW) cows from a private herd. In the research herd, two groups of eight HF cows were investigated: group B (OPU once weekly) and group C (OPU twice weekly). The collected oocytes were subsequently submitted to in vitro embryo production. More oocytes were recovered from the private herd when compared with the research herd. In the research herd, the twice weekly scheme aspirated more oocytes than the once weekly scheme. The quality of the retrieved oocytes was significantly different between groups B and C but not between groups A and C, and HF cows yielded higher quality oocytes than DRW cows (p = 0.029). Oocytes from group C showed higher level of embryonic development than group B oocytes. No differences in blastocyst rates were observed between groups A and C. Session affected the number of retrieved oocytes and subsequent developmental rates, with these being lower in the first compared with the last sessions. Finally, there was no significant effect of days post-partum in the number and quality of the retrieved oocytes, likely because of the small group size and high variation between sessions.
Reproduction in Domestic Animals 07/2006; 41(3):196-203. · 1.36 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Oxygen consumption is a useful parameter for evaluating embryo quality, since it provides a valuable indication of overall metabolic activity. Over the years, several approaches have been used to measure the respiration rates of individual embryos, but a convincing method has not yet been reported. In this study, we introduce and have validated a novel high resolution microsensor technology to determine the respiration rates of individual embryos at different developmental stages. We have employed this technology to investigate the correlation between respiration rate and embryo morphology, diameter and sex. Following morphological evaluation, individual respiration rates of day 3 (n = 18) and day 7 (n = 60) bovine in vitro-produced embryos were determined. Of the measured embryos, 64 were lysed for sex diagnosis by PCR. Average respiration rates of day 7 embryos (1.30 +/- 0.064 nl/h) were 3.4-fold higher than day 3 embryos (0.38 +/- 0.011 nl/h). On day 7, the average respiration rate of quality 1 blastocysts was significantly higher than the respiration rates of the lower qualities. For both day 3 and day 7 embryos, respiration rates were directly influenced by embryo diameter but did not differ between sexes. These results have demonstrated that the novel microsensor technology can be used to accurately and rapidly (8 min) measure the respiration rates of individual embryos at different developmental stages. Respiration rates were only in partial agreement with embryo morphology, suggesting a slight discrepancy between these two methods in assessing embryo quality. It is likely that a combined assessment of embryo respiration and morphology would improve embryo classification and subsequent selection.
Reproduction (Cambridge, England) 12/2005; 130(5):669-79. · 3.09 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: During the past thirty years, basic and experimental studies on classical (superovulation; non-surgical recovery and transfer of cattle embryos) and advanced embryo technologies (in vitro embryo production; cloning by somatic cell nuclear transfer) have generated structural and functional information on oocyte development and quality, fertilisation and conceptus development. This information has provided new insight, not only into these technologies per se but also into the factors contributing to fertility in cattle. It is now known that the peripheral and follicular endocrine profiles have a profound influence on the subsequent developmental competence of the embryo. It is also well established that manipulation of the oocytes or embryos may adversely affect embryonic and foetal development, leading to the so-called 'large offspring syndrome'. Information from such studies has alerted scientists to the importance of epigenetics in cattle reproduction.
Revue scientifique et technique (International Office of Epizootics) 05/2005; 24(1):405-12. · 1.10 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: This essay is concerned with the function of ovarian somatic cells, especially those of the cumulus oophorus, that are shed with the oocyte at the time of ovulation. Once dissociated from the surface of the oocyte(s), they remain in its close vicinity or that of the zygote(s) throughout the tubal sojourn. Most such follicular cells are not moribund or dead but continue to be synthetically active, although showing ultrastructural modification. Their secretions may include steroid hormones, prostaglandins and diverse peptides, molecules that would be presented locally to the endosalpinx. The cell suspension represents a potential route of amplification of early pregnancy signals from the embryo to influence the pattern of ovarian steroid secretion and perhaps that of folliculogenesis. Bearing in mind the relatively low concentration of hormones generated by the somatic cell suspension, vascular counter-current transfer of information is postulated from the Fallopian tube to the ipsilateral ovary. Molecular techniques are being applied as a means of examining endosalpingeal responses in four different experimental models in which the numbers and presumptive activity of suspended follicular cells are varied in pigs with spontaneous oestrous cycles. Because these animals ovulate on both ovaries, epithelial activity can be compared and contrasted between the two sides. In a final model, attempts are being made to generate early pregnancy responses in the absence of embryos by transplanting zygote-programmed cumulus cells from a mated donor into the Fallopian tube of an unmated recipient.
Italian journal of anatomy and embryology = Archivio italiano di anatomia ed embriologia 02/2005; 110(2 Suppl 1):195-203.
-
[show abstract]
[hide abstract]
ABSTRACT: Glucocorticoids play an important role in prenatal organ maturation in many species. In humans, maternal treatment with synthetic glucocorticoids improves neonatal adaptation of prematurely born infants. In cows, pre-term calf survival is improved following a single maternal glucocorticoid administration. We hypothesized that stimulation of endogenous cortisol secretion by adrenocorticotropin (ACTH) treatment combined with maternal dexamethasone treatment, would be even more efficient in stimulating organ maturation in the prematurely delivered calf. Three groups of premature calves were delivered by caesarian section at 90% of gestation length from dams which were either untreated or injected with dexamethasone before delivery, combined with either prenatal or postnatal ACTH treatment to the calf. During the first 24h after birth, thermoregulation, blood chemistry, liver values and organ weights were recorded. In the untreated calves, survival was significantly correlated with blood oxygenation, sodium and calcium levels at the moment of birth. There were marked maturational effects of the treatments on body temperature regulation, blood acid-base status, oxygenation, glucose, insulin, IGF-1 levels, weight of the heart, liver, gastrointestinal tract and thymus weight. For many of the measured metabolic, endocrine and organ weight parameters, the intrauterine ACTH treatment was associated with improved values relative to the postnatal ACTH treatment, which appeared to have no immediate effect on calf viability. In conclusion, the premature calf delivered by caesarian section at 90% of gestation length showed blood chemistry, metabolic, endocrine and organ growth characteristics that indicated severe prematurity. However, the maturation of organ function in newborn premature calves following maternal glucocorticoid injections was further enhanced if is was preceded by intra-fetal injections of ACTH.
Theriogenology 07/2004; 61(9):1729-44. · 1.96 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Surgical intervention in general anesthesia (GA) of the cow in late gestation is a stressful condition for both mother and fetus, potentially leading to premature delivery or fetal death. The present study hypothesized that fetal catheterization at days 246-253 (90% of gestation) is done with less physical and metabolic stress for the mother and fetus, when the surgery is performed on a standing cow and local anesthesia (LA) rather than on a recumbent cow in general anesthesia. Fetal and uterine maternal intra-vascular catheters were implanted during general anesthesia (GA, n=24) or local analgesia (LA, n=7). Blood gases and metabolite levels in the fetal calves and their mothers were measured during surgery and for 5 days post-operatively. During surgery, venous blood pH was higher (7.44 +/- 0.01 versus 7.39 +/- 0.01, P<0.05) and hemoglobin and oxygen contents lower in LA cows compared with GA cows (9.3 +/- 0.3 mg/dl versus 11.8 +/- 0.2 mg/dl, P<0.001 and 10.0 +/- 0.3 ml/dl versus 12.6 +/- 0.6 ml/dl, P<0.05). The differences between the two groups of fetuses reflected those of their dams in that LA fetuses showed lower arterial oxygen pressure (18.3 +/- 1.4 mmHg versus 24.8 +/- 1.4 mmHg, P<0.05) and hemoglobin (7.81 +/- 0.30 mg/dl versus 9.22 +/- 0.21 mg/dl P<0.01) and furthermore, they also showed higher blood glucose (2.4 +/- 0.2 mM versus 1.4 +/- 0.1 mM, P<0.01). During the 5 days post-surgery, 10 GA fetuses (42%) and 1 LA fetus (14%) died in utero. Bacterial contamination was implicated in six of the GA deaths and in the one LA death. In the dams with surviving calves, differences in hemoglobin (9.49 +/- 0.21 mg/dl versus 11.17 +/- 0.23 mg/dl P<0.001) and O2ct (10.9 +/- 0.3 ml/dl versus 12.5 +/- 0.5 ml/dl, P<0.05) were still present, and in addition, blood glucose was higher in LA versus GA cows (4.3 +/- 0.2 mM versus 3.8 +/- 0.1 mM, P<0.05). The choice of surgical method did not affect post-surgery blood chemistry in the surviving fetuses, except that the higher blood glucose in the LA fetuses at surgery tended to be maintained also post-operatively (2.0 +/- 0.2 mM versus 1.5 +/- 0.1 mM, P=0.07). The observed differences in blood chemistry parameters between the two methods of surgery and possibly in the fetal death may be explained by differences in catheterization method and the associated differences in physical and metabolic stress during and after surgery. Thus, surgery upon a standing cow in local anesthesia should be considered as an alternative to surgery in universal anesthesia for fetal catheterization in the cow in late gestation.
Animal Reproduction Science 03/2004; 80(3-4):193-200. · 1.75 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: In the mare, ultrasound-guided transvaginal oocyte recovery and transfer might offer a way to circumvent the demanding procedures of in vitro embryo production. Before clinical application, the possible consequences for subsequent fertility have to be considered.
To examine ovarian function and morphology in mares after repeated follicular punctures.
A total of 14-26 follicular puncture sessions were conducted on each of 4 Norwegian pony mares over a period of 8 years. The ovaries of these mares were recovered by bilateral ovariectomy or at post mortem and subjected to macroscopic inspection and histology. For comparison, ovaries were collected from 7 nonaspirated control mares and processed for histology.
In all experimental mares, ovarian function, defined as the ability regularly to ovulate preovulatory follicles and develop corpora lutea, remained normal during their last breeding season. Gross examination and histology showed that normal follicular and corpus luteum development was accompanied by the formation of condensed reparative fibrosis and normal local haemosiderosis of the ovarian stroma in all experimental mares. In one mare, an ovary contained several foci of chronic apostematous oophoritis, while a cystic structure lined with a single layer of epithelial-like cells and surrounded by a cartilaginous capsule was present in the other ovary.
Repeated follicular aspirations do not hamper future folliculogenesis, ovulation and corpus luteum formation. However, ovarian puncture induces reparative fibrosis in the ovarian stroma and involves a risk of inducing abscess formation within the ovarian tissue which may impair fertility.
Equine Veterinary Journal 10/2003; 35(6):575-9. · 1.46 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: The general objective of this study was to perform follow-up studies including selected peri- and postnatal characteristics on calves born after transfer of in vitro produced (IVP) embryos vitrified by the 'Open Pulled Straw' (OPS) method. An overall pregnancy rate of 16% after transfer of the OPS-vitrified IVP embryos was achieved and resulted in birth of 9 calves, with 11 AI calves serving as controls. There were no immediate or long-term effects on these calves with respect to birth weight, gestation length, perinatal mortality, growth rate, disease susceptibility and reproductive performance.
Acta veterinaria Scandinavica 02/2003; 44(1-2):87-95. · 1.37 Impact Factor
-
[show abstract]
[hide abstract]
ABSTRACT: Earlier reports indicate that calves derived from in vitro produced (IVP) embryos are more susceptible to neonatal disease than calves produced after artificial insemination (AI) or natural mating. The aims of the present study were to investigate whether calves born after IVP embryos show an altered macromolecule absorption (immunoglobulin G (IgG) and porcine serum albumin (PSA)) compared with AI calves and whether the macromolecule absorption could be related to the degree of acidosis or to the cortisol secretion around birth. Hence, IgG and PSA absorption in control AI calves (n=7) was compared with that in two groups of IVP calves (IVP-defined: SOFaa embryo culture with polyvinyl alcohol, n=6; IVP-serum: SOFaa embryo culture with serum and co-culture, n=8). The calves were fed colostrum (40ml/kg) at 2, 6 and 12h after birth. At 24h after birth, both AI and IVP calves had achieved a level of plasma IgG sufficient to provide passive immunization (>15mg/ml). When the values were adjusted for the varying colostral IgG contents and the degree of acidosis, the IVP-defined calves had significantly lower peak plasma IgG concentrations than the AI calves at 18-24h after birth (P<0.04). However, when the macromolecule marker (PSA), was fed to all calves at 2 and 12h after birth the resulting plasma PSA levels were significantly lower in the AI calves compared with the IVP calves during the whole observation period (P<0.0001). Calves with a moderate neonatal acidosis (mean pH<7.2 during the first 30min after birth) had reduced peak plasma IgG concentration at 18-24h after birth (P<0.02) compared to calves without acidosis. The basal and ACTH-stimulated cortisol levels were lower in the newborn IVP-defined calves than in the AI calves (P<0.05) and the IVP-serum calves (P<0.002). Cortisol levels shortly after birth correlated positively with birth weight (r=0.60, P<0.0001) and with gestation length (r=0.34, P<0.04). Since, the IVP calves absorbed sufficient amounts of IgG from colostrum to acquire sufficient passive immunity, we conclude that the lower viability described in IVP offspring probably is not caused by an impaired passive immunization. IVP-defined calves had significantly lower absorption efficiency of IgG compared with AI calves, whereas absorption of a non-Ig macromolecule (PSA) was higher for IVP than AI calves. This might indicate a more selective absorption in AI calves in favor of IgG. Acidosis around birth affected immunoglobulin absorption negatively. IVP-defined calves had significantly lower cortisol levels the first 3h after birth and during an ACTH-challenge and a lower IgG absorption efficiency, which might indicate a mild degree of organ dysmaturity in these calves.
Animal Reproduction Science 04/2002; 70(1-2):1-11. · 1.75 Impact Factor
