Application of the bovine model for the study of ovarian function in other species

A research model is a general pattern that scientists use as a tool to investigate a general phenomenon. Research models usually imply the use of specific techniques (e.g., ultrasonography) and experimental units (e.g., animals) with which data were originally gathered and patterns were originally defined. Research models offer a conceptual framework upon which specific hypotheses may be formed and tested, and they permit the extension of a concept into new areas (e.g., different species). Good research models are readily accessible (i.e., abundant and inexpensive), malleable (i.e., easy to work with and adaptable), of broad applicability, and lend themselves to quantitative assessment. Ovarian function is perhaps most studied and best understood in the bovine species. Through the use of ultrasound imaging, studies in the bovine species have served as a template for elucidating physiologic mechanisms related to ovarian function and for characterizing reproductive events in many other species, including humans [5]. The following is intended as an overview of the bovine model for studying ovarian function and its remarkable impact on our understanding of the reproductive biology of many other domestic and non-domestic species. Examples of findings in other species are drawn primarily from studies in the author’s laboratory, and hence, is not intended as a comprehensive review

Ovulation-inducing factor: a protein component of llama seminal plasma

<p>Abstract</p> <p>Background</p> <p>Previously, we documented the presence of ovulation-inducing factor (OIF) in the seminal plasma of llamas and alpacas. The purpose of the study was to define the biochemical characteristics of the molecule(s) in seminal plasma responsible for inducing ovulation.</p> <p>Methods</p> <p>In Experiment 1, llama seminal plasma was centrifuged using filtration devices with nominal molecular mass cut-offs of 30, 10 and 5 kDa. Female llamas (n = 9 per group) were treated i.m. with whole seminal plasma (positive control), phosphate-buffered saline (negative control), or the fraction of seminal plasma equal or higher than 30 kDa, 10 to 30 kDa, 5 to 10 kDa, or < 5 kDa. In Experiment 2, female llamas (n = 7 per group) were given an i.m. dose of seminal plasma treated previously by: 1) enzymatic digestion with proteinase-K, 2) incubation with charcoal-dextran, 3) heating to 65°C, or 4) untreated (control). In Experiment 3, female llamas (n = 10 per group) were given an i.m. dose of pronase-treated or non-treated (control) seminal plasma. In all experiments, llamas were examined by transrectal ultrasonography to detect ovulation and CL formation. Ovulation rate was compared among groups by Fisher's exact test and follicle and CL diameters were compared among groups by analyses of variance or student's t-tests.</p> <p>Results</p> <p>In Experiment 1, all llamas in the equal or higher than 30 kDa and positive control groups ovulated (9/9 in each), but none ovulated in the other groups (P < 0.001). In Experiment 2, ovulations were detected in all llamas in each treatment group; i.e., respective treatments of seminal plasma failed to inactivate the ovulation-inducing factor. In Experiment 3, ovulations were detected in 0/10 llamas given pronase-treated seminal plasma and in 9/10 controls (P < 0.01).</p> <p>Conclusions</p> <p>We conclude that ovulation-inducing factor (OIF) in llama seminal plasma is a protein molecule that is resistant to heat and enzymatic digestion with proteinase K, and has a molecular mass of approximately equal or higher than 30 kDa.</p

Local versus systemic effect of ovulation-inducing factor in the seminal plasma of alpacas

BACKGROUND: Camelids are induced (reflex) ovulators. We have recently documented the presence of an ovulation-inducing factor (OIF) in the seminal plasma of alpacas and llamas. The objective was to test the hypothesis that OIF exerts its effect via a systemic rather than a local route and that endometrial curettage will enhance the ovulatory response to intrauterine deposition of seminal plasma in alpacas. METHODS: Female alpacas were assigned randomly to 6 groups (n = 15 to 17 per group) in a 2 × 3 factorial design to test the effect of seminal plasma versus phosphate-buffered saline (PBS) given by intramuscular injection, by intrauterine infusion, or by intrauterine infusion after endometrial curettage. Specifically, alpacas in the respective groups were given 1) 2 ml of alpaca seminal plasma intramuscularly, 2) 2 ml of PBS intramuscularly (negative control group), 3) 2 ml of alpaca seminal plasma by intrauterine infusion, 4) 2 ml of PBS by intrauterine infusion (negative control group), 5) 2 ml of alpaca seminal plasma by intrauterine infusion after endometrial curettage, or 6) 2 ml of PBS by intrauterine infusion after endometrial curettage (negative control group). The alpacas were examined by transrectal ultrasonography to detect ovulation and measure follicular and luteal diameters. RESULTS: Intramuscular administration of seminal plasma resulted in a higher ovulation rate than intrauterine administration of seminal plasma (93% versus 41%; P < 0.01), while intrauterine seminal plasma after endometrial curettage was intermediate (67%). None of the saline-treated controls ovulated. The diameter of the CL after treatment-induced ovulation was not affected by the route of administration of seminal plasma. CONCLUSION: We conclude that 1) OIF in seminal plasma effects ovulation via a systemic rather than a local route, 2) disruption of the endometrial mucosa by curettage facilitated the absorption of OIF and increased the ovulatory effect of seminal plasma, and 3) ovulation in alpacas is not associated with a physical stimulation of the genital tract, and 4) the alpaca represents an excellent biological model to evaluate the bioactivity of OIF

Ultrasonic Imaging of Reproductive Events in Muskoxen

To our knowledge, this is the first detailed report of ovarian follicular dynamics in a wild species. It seems that the pattern in muskoxen, with major and minor waves and a short first cycle, is similar to that in goats. Insight of this kind is important in the design of appropriate artificial breeding systems and in this respect, the muskox may provide a useful model for the endangered takin {Budorcas taxicolor). A detailed knowledge of ovarian events may also be critical to the interpretation of the response of wild populations to environmental stress

Level set segmentation of bovine corpora lutea in ex situ ovarian ultrasound images

<p>Abstract</p> <p>Background</p> <p>The objective of this study was to investigate the viability of level set image segmentation methods for the detection of corpora lutea (corpus luteum, CL) boundaries in ultrasonographic ovarian images. It was hypothesized that bovine CL boundaries could be located within 1–2 mm by a level set image segmentation methodology.</p> <p>Methods</p> <p>Level set methods embed a 2D contour in a 3D surface and evolve that surface over time according to an image-dependent speed function. A speed function suitable for segmentation of CL's in ovarian ultrasound images was developed. An initial contour was manually placed and contour evolution was allowed to proceed until the rate of change of the area was sufficiently small. The method was tested on ovarian ultrasonographic images (<it>n </it>= 8) obtained <it>ex situ</it>. A expert in ovarian ultrasound interpretation delineated CL boundaries manually to serve as a "ground truth". Accuracy of the level set segmentation algorithm was determined by comparing semi-automatically determined contours with ground truth contours using the mean absolute difference (MAD), root mean squared difference (RMSD), Hausdorff distance (HD), sensitivity, and specificity metrics.</p> <p>Results and discussion</p> <p>The mean MAD was 0.87 mm (sigma = 0.36 mm), RMSD was 1.1 mm (sigma = 0.47 mm), and HD was 3.4 mm (sigma = 2.0 mm) indicating that, on average, boundaries were accurate within 1–2 mm, however, deviations in excess of 3 mm from the ground truth were observed indicating under- or over-expansion of the contour. Mean sensitivity and specificity were 0.814 (sigma = 0.171) and 0.990 (sigma = 0.00786), respectively, indicating that CLs were consistently undersegmented but rarely did the contour interior include pixels that were judged by the human expert not to be part of the CL. It was observed that in localities where gradient magnitudes within the CL were strong due to high contrast speckle, contour expansion stopped too early.</p> <p>Conclusion</p> <p>The hypothesis that level set segmentation can be accurate to within 1–2 mm on average was supported, although there can be some greater deviation. The method was robust to boundary leakage as evidenced by the high specificity. It was concluded that the technique is promising and that a suitable data set of human ovarian images should be obtained to conduct further studies.</p

Cetrorelix suppresses the preovulatory LH surge and ovulation induced by ovulation-inducing factor (OIF) present in llama seminal plasma

<p>Abstract</p> <p>Background</p> <p>The purpose of the study was to determine if the effect of llama OIF on LH secretion is mediated by stimulation of the hypothalamus or pituitary gland.</p> <p>Methods</p> <p>Using a 2-by-2 factorial design to examine the effects of OIF vs GnRH with or without a GnRH antagonist, llamas with a growing ovarian follicle greater than or equal to 8 mm were assigned randomly to four groups (n = 7 per group) and <b>a) </b>pre-treated with 1.5 mg of GnRH antagonist (cetrorelix acetate) followed by 1 mg of purified llama OIF, <b>b) </b>pre-treated with 1.5 mg of cetrorelix followed by 50 micrograms of GnRH, <b>c) </b>pre-treated with a placebo (2 ml of saline) followed by 1 mg of purified llama OIF or <b>d) </b>pre-treated with a placebo (2 ml of saline) followed by 50 micrograms of GnRH. Pre-treatment with cetrorelix or saline was given as a single slow intravenous dose 2 hours before intramuscular administration of either GnRH or OIF. Blood samples for LH measurement were taken every 15 minutes from 1.5 hours before to 8 hours after treatment. The ovaries were examined by ultrasonography to detect ovulation and CL formation. Blood samples for progesterone measurement were taken every-other-day from Day 0 (day of treatment) to Day 16.</p> <p>Results</p> <p>Ovulation rate was not different (P = 0.89) between placebo+GnRH (86%) and placebo+OIF groups (100%); however, no ovulations were detected in llamas pre-treated with cetrorelix. Plasma LH concentrations surged (P < 0.01) after treatment in both placebo+OIF and placebo+GnRH groups, but not in the cetrorelix groups. Maximum plasma LH concentrations and CL diameter profiles did not differ between the placebo-treated groups, but plasma progesterone concentrations were higher (P < 0.05), on days 6, 8 and 12 after treatment, in the OIF- vs GnRH-treated group.</p> <p>Conclusion</p> <p>Cetrorelix (GnRH antagonist) inhibited the preovulatory LH surge induced by OIF in llamas suggesting that LH secretion is modulated by a direct or indirect effect of OIF on GnRH neurons in the hypothalamus.</p

Sheep Updates 2005 - Part 3

This session covers seven papers from different authors: CUSTOMER 1. Benefits VIAscanR to producers and WAMMCO, Rob Davidson, Supply Development Manager, David Pethick, School of Veterinary and Biomedical Studies, Murdock University. 2. Healthy fats in lamb: how WA lambs compare with others, C. F. Engelke Animal Biology, University of Western Australia, bCSIRO Livestock Industries, Western Australia B.D. Siebert, Department of Animal Science, University of Adelaide, South Australia, K. Gregg, Centre for High-Throughput Agricultural Genetic Analysis, Murdoch University, Western Australia. A-D.G. Wright CSIRO Livestock Industries, Western Australia, P.E Vercoe Animal Biology, University of Western Australia 3. Shelf life of fresh lamb meat: lamb age & electrical stimulation, Dr Robin Jacob, Department of Agriculture, Western Australia 4. Pastures from space - An evaluation of adoption of by Australian woolgrowers, Russell Barnett, Australian Venture Consultants, Joanne Sneddon, University of Western Australia 5. Your clients can learn from ASHEEP\u27s example, Sandra Brown Department of Agriculture Western Australia 6. Lifetime Wool - Farmers attitudes affect their adoption of recommended ewe management, G. Rose Department of Agriculture Western Australia, C. Kabore, Kazresearch, Lower Templestowe Vic, J. Dart, Clear Horizons, Hastings Vic 7. Sustainable certification of Australian Merino, what will customers be looking for? Stuart Adams, i-merino / iZWool International Pty Lt

Greed, recklessness and/or dishonesty? An investigation into the micro-regulation and culture of five UK banks between 2004-2009

The author uses a multiple case study approach to examine five UK banks in her paper. The banks are Northern Rock, the Royal Bank of Scotland, Barclays, Lloyds Banking Group and HSBC. The author feels that it is appropriate to use a multiple case study here because it will be interesting to study the micro aspects of regulation and corporate governance of five UK banks. The banks have to comply with the same regulations and laws on a macro level, so it is essential to examine the differences between these banks on a micro level through reviewing annual reports and financial ratios. The case study is longitudinal, spanning across 2004-2009. In accordance to the aims of a case study, the author will describe, understand and explain the effects of the financial crisis 2007 on five UK banks. This case study provides an opportunity to examine the weaknesses and failures of corporate governance of five UK banks at a micro level. The author has two hypotheses at the beginning of the study. First, banks moved from a customer driven culture to sales driven one. Secondly, the banking culture during between 2004-2009 is one of greed, recklessness and dishonesty. With the caveat that one should not make generalisations, there is evidence from the case study that both hypotheses are correct to a certain extent