Gonadotrophin-releasing hormone treatment in cattle: a meta-analysis of the effects on conception at the time of insemination   总被引：1，自引：0，他引：1  

WF MORGAN  IJ LEAN 《Australian veterinary journal》1993,70(6):205-209

SUMMARY Data from 40 trials described in 27 published papers were analysed by meta-analysis (pooling of data from numerous trials into a single analysis) to evaluate the effects of injecting gonadotrophin-releasing hormone (GnRH) In cattle at the time of Insemination on the risk of pregnancy. A total of 19 019 cows were involved In these studies. Analyses were stratified by trial and by the effects of dose of GnRH, type of GnRH and Insemination number (first, second or third and greater). Mantel-Haenszel analysis revealed that use of GnRH at Insemination significantly Increased the overall risk of pregnancy by 12.5% In treated cows (P < 0.05). However, Increases In risk of pregnancy were greatest (22.5%) when repeat breeders were treated. Results for use of GnRH or analogue at first service were similar, with Increased risks of pregnancy in treated cows of 5.2 and 8.0%, respectively. The risk of pregnancy tended to be higher (11.1%) when the dose of GnRH was 250 μg and when used at second Insemination (9.9%). The analyses demonstrated that while treatment at Insemination with GnRH and GnRH analogues Increased conception rates In dairy cattle, some variation In study results was attributable to the number of Inseminations after calving at which GnRH Is administered. Further efforts should be made to determine characteristics of populations of cows that have good fertility responses to GnRH and to determine the mode of action of GnRH in Increasing fertility. Meta-analysis proved to be a useful technique for evaluating the apparently conflicting results from trials and in evaluating the effect of factors such as Insemination number, dose and type of GnRH on responses to treatment.  相似文献   

Serotyping of isolates of Pasteurella multocida from chickens     

LA IRELAND  AR MILNER  IJ SMART 《Australian veterinary journal》1989,66(4):119-120

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AN ATTEMPT TO PHOTOGRAPH THE SOLAR CORONA WITHOUT AN ECLIPSE     

Pickering WH 《Science (New York, N.Y.)》1885,6(132):131-133

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Measurement of the speed of photographic drop-shutters     

Pickering WH 《Science (New York, N.Y.)》1884,4(93):454-456

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A case-control study to identify farm factors affecting fertility of dairy herds: univariate description of factors     

FB WEBSTER  IJ LEAN  D. KENNEDY  K. PHILLIPS 《Australian veterinary journal》1997,75(4):266-273

Objective To identify farm factors which were associated with reproductive performance in dairy herds in New South Wales.
Procedure A survey was administered by face to face interview to examine the responses of producers drawn from 757 herds, which used the New South Wales Agriculture Department Dairy Herd Improvement scheme. A case-control approach was used to select a total of 126 herds from the first (top group - cases) and fourth quartiles (low group - controls) for intercalving interval.
Results We found that the estimated interval from calving to first mating was significantly different between groups (P = 0.03) and that the groups significantly differed in both their target for interval to first mating (P = 0.02) and their perceived optimum time for first mating (P = 0.04). Other factors associated with a longer intercalving interval included, use of embryo transfer programs (P = 0.08), younger managers (P = 0.02), fewer breedings per day (P = 0.01), a greater number of people detecting heats (P = 0.07), but less hours spent detecting heats while handling the cows (P = 0.11), and a failure to vaccinate bulls for campylobacteriosis (P = 0.14).
Conclusions Managers of herds with poorer reproductive performance did not intend to mate cattle as soon after calving as managers with better reproductive performance, were not as active in seeking veterinary advice on reproduction, and were attempting to treat reproductive diseases and disorders themselves.  相似文献   

THE AIMS OF AN ASTRONOMER     

Pickering EC 《Science (New York, N.Y.)》1906,24(603):65-71

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Analysis of green hemp fibre reinforced composites using bag retting and white rot fungal treatments     

Yan Li  K.L. Pickering  R.L. Farrell 《Industrial Crops and Products》2009,29(2-3):420-426

The main objective of this project was to investigate two low cost treatment methods, namely bag retting and treatment with white rot fungi, which could be applied to hemp fibre with low environmental impact to improve its interfacial bonding with polypropylene. Wet chemical analysis, FTIR, scanning electron microscopy (SEM), X-ray diffraction (XRD), zeta potential and single fibre tensile testing were used to characterise the effect of treatment on hemp fibres. It was found that all the treatments increased the tensile strength of composites. White rot fungi Schizophyllum commune (S.com) treated fibre composites had the highest tensile strength of 45 MPa, an increase of 28% compared to composites using untreated fibre.  相似文献   

THE ENDOWMENT OF RESEARCH     

Pickering EC 《Science (New York, N.Y.)》1901,13(319):201-202

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The Soaring of Birds     

Pickering WH 《Science (New York, N.Y.)》1889,13(321):245-246

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PHOTOGRAPHIC STUDY OF STELLAR SPECTRA     

Pickering EC 《Science (New York, N.Y.)》1886,7(164):278-279

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