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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
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
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L J Kamin L E Moses S A Mednick W F Gabrielli B Hutchings 《Science (New York, N.Y.)》1985,227(4690):983-4,986,989
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Two Scottish Deerhound puppies had clinical and pathological features consistent with the diagnosis of congenital non-goitrous hypothyroidism. They were from separate litters, but were the progeny of the same sire and dam. The puppies were smaller, had shorter limbs and shorter, broader heads than their littermates. They also had histories of weakness, difficulty in walking and somnolence. A characteristic radiographic feature was the absence of epiphyseal growth centres. Both had depressed serum thyroxine (T4) levels and one did not respond to exogenous thyroid stimulating hormone. On necropsy, the thyroid glands were small, the follicles varied in size and contained little or no colloid. The adenohypophysis contained many cells with markedly vacuolated cytoplasm. It is suggested that the clinicopathological pattern is the result of a primary thyroid abnormality. Possible mechanisms include either primary thyroid hypoplasia or an unresponsiveness to thyroid stimulating hormone. 相似文献
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Aluminas and their surface chemistry play a vital role in many areas of modern technology. The behavior of adsorbed water is particularly important and poorly understood. Simulations of hydrated alpha-alumina (0001) surfaces with ab initio molecular dynamics elucidate many aspects of this problem, especially the complex dynamics of water dissociation and related surface reactions. At low water coverage, free energy profiles established that molecularly adsorbed water is metastable and dissociates readily, even in the absence of defects, by a kinetically preferred pathway. Observations at higher water coverage revealed rapid dissociation and unanticipated collective effects, including water-catalyzed dissociation and proton transfer reactions between adsorbed water and hydroxide. The results provide a consistent interpretation of the measured coverage dependence of water heats of adsorption, hydroxyl vibrational spectra, and other experiments. 相似文献
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Cancrini G Frangipane di Regalbono A Ricci I Tessarin C Gabrielli S Pietrobelli M 《Veterinary parasitology》2003,118(3-4):195-202
Investigations were carried out in Padova town (Veneto region, NE Italy) to define the actual role of Aedes albopictus in the natural transmission of Dirofilaria nematodes, and to assess the risk that its presence might represent for veterinary and medical health. During summer 2000-2002 daytime captures of human-attracted mosquitoes were carried out in three areas of the town. The presence of filarial parasites in mosquitoes was evaluated by PCR, and sequencing confirmed species assessment. DNA extraction was performed separately on pools of the insect abdomen and thorax-head, to discriminate between Dirofilaria infected/infective specimens. A total of 2721 mosquitoes were caught and A. albopictus was the most abundant species (2534). Filarial DNA was found in 27.5% (19/69) of the abdomen pools formed with mosquitoes collected in summer 2000, and in 11.1% (16/144) and 4.9% (6/123) thorax-head pools coming from samplings 2001 and 2002, respectively. Filarial DNA was belonging to D. immitis and all studied areas harboured infective specimens. These results prove A. albopictus as natural vector of D. immitis in Italy. Moreover, they support the hypothesis that the presence of the mosquito could affect the transmission pattern of canine heartworm disease in urban environment and, considering the aggressive anthropophylic behaviour of the species (30-48 bites/h) proven in Padova town, could enhance the circulation of filarial nematodes from animals to humans. 相似文献
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The objective of this study was to examine the differences in sow metacarpal properties through various parities and to compare the incidence of locomotory problems between stalled and loose-housed sows. Metacarpals (n = 110) of sows from six farms were collected at slaughter and stored at -20°C. Bones from one forelimb of sows in stalls (n = 36) and loose-housed (n = 20) were collected and their articular surfaces examined for Osteochondrosis Dissecans (OCD), these sows were also scored for lameness pre-slaughter. Metacarpals were CT scanned for cross sectional area and moment of inertia. Cylindrical sections from the diaphysis were used for mechanical testing and calculating bone strength indices. The results show there was little change in bone mineral status throughout the range of parities examined and overall metacarpal integrity was not compromised by multiple production cycles. There were no differences detected in the incidence of lameness or joint pathology between housing systems. 相似文献
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WF Swanson RR Valle FM Carvalho PR Arakaki AZ Rodas‐Martínez JAPC Muniz M García‐Herreros 《Reproduction in domestic animals》2016,51(4):623-627
The main objective of this study was to evaluate sperm morphology in four neotropical primate species to compare the sperm morphological traits and the sperm morphometric parameters as a basis for establishing normative sperm standards for each species. Data from 80 ejaculates collected from four primate species, Callithrix jacchus, Callimico goeldii, Alouatta caraya and Ateles geoffroyi, were analysed for detection of sperm morphological alterations using subjective World Health Organization (WHO‐2010) standards and Sperm Deformity Index (SDI) criteria, objective computer‐assisted sperm morphometry analysis (CASMA) and subpopulation sperm determination (SSD) methods. There were multiple differences (p < 0.01) observed among primate species in values obtained from WHO‐2010, SDI, CASMA and SSD sperm analysis methods. In addition, multiple significant positive and negative correlations were observed between the sperm morphological traits (SDI, Sperm Deformity Index Head Defects, Sperm Deformity Index Midpiece Defects, Sperm Deformity Index Tail Defects, Normal Sperm, Head Defects, Midpiece Defects and Tail Defects) and the sperm morphometric parameters (SSD, Area (A), Perimeter (P), Length (L), Width (W), Ellipticity, Elongation and Rugosity) (p ≤ 0.046). In conclusion, our findings using different evaluation methods indicate that pronounced sperm morphological variation exists among these four neotropical primate species. Because of the strong relationship observed among morphological and morphometric parameters, these results suggest that application of objective analysis methods could substantially improve the reliability of comparative studies and help to establish valid normative sperm values for neotropical primates. 相似文献
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The possibility that genetic factors are among the causes of criminal behavior was tested by comparing court convictions of 14,427 adoptees with those of their biological and adoptive parents. A statistically significant correlation was found between the adoptees and their biological parents for convictions of property crimes. This was not true with respect to violent crimes. There was no statistically significant correlation between adoptee and adoptive parent court convictions. Siblings adopted separately into different homes tended to be concordant for convictions, especially if the shared biological father also had a record of criminal behavior. 相似文献