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Horses with undescended testes are frequently presented to the veterinary surgeon for castration. The pertinent pre-operative evaluations and diagnostic procedures that should be made prior to either surgical intervention or referral of such cases are outlined. Several accepted anesthetic and surgical techniques are similarly reviewed. Case histories of 58 horses referred during a two year period are reviewed and correlated with the findings of a recent study of equine testicular development and descent.  相似文献   
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A large-scale and long-term research and development project Forest management inspired by natural disturbance dynamics (DISTDYN) was initiated in Finland in 2009. The aim is to examine how variation in spatial and temporal scales of felling affects forest structure and biota. Harvesting methods applied in this project include selection, gap, partial and clear felling with variable retention. Rehabilitation is also applied as dead wood is intentionally increased while harvesting. The motivation of the project lies in the growing interest in using natural disturbances as an inspiration of forest-ecosystem management and in the recognition that mid- to small-scale disturbances are a characteristic feature of unmanaged Fennoscandian forests. The effects of felling methods are studied at the stand scale. However, a unique aspect of the project is the focus on landscape-scale impacts of different harvesting alternatives by comparing ca. 150-ha landscape units with varying harvesting regimes. Overall, the project aims at creating a long-lasting multidisciplinary research infrastructure. It also addresses core issues of forest-ecosystem management, including ecological, timber-production, economic and socio-cultural performances of alternative harvesting practices.  相似文献   
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A rapid and sensitive method is described for the quantitation of erythromycin A (EA) in edible salmon tissue by liquid chromatography (LC) analysis using either electrochemical detection (ED) or electrospray ionization mass spectrometric (ESI/MS) detection. The salmon tissue is extracted with 10 mM ammonium formate. The extract is then purified by solid phase extraction using a hydrophilic-lipophilic balanced (HLB) polymeric-based C18 packing, followed by partitioning of EA into methylene chloride at alkaline pH, evaporation, and final dilution. The mean recoveries of EA at 50, 100, 200, and 400 ppb levels in fortified salmon tissue were 63.8 +/- 6.0 and 75.5 +/- 5.4% by LC-ED and LC-ESI/MS, respectively. There was no evidence of formation of the anhydro-EA (m/z 716) decomposition product of EA (m/z 734) that was reported to occur by other published methods.  相似文献   
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Polypore communities were compared between mature managed, overmature managed, and old-growth spruce-dominated forests in southern Finland. A total of 85 polypore species, with 6000 records, were found in 16 sample plots, each 4 ha in size. Old-growth stands had on average 80% more species than mature stands, and 38% more species than overmature managed stands. Variation in polypore species richness was best explained by diversity of dead wood and the number and volume of dead trees. The best predictor for the number of threatened polypore species was the number of cut stumps. Threatened species were practically confined to old-growth forests and to stands in which the amount of dead wood exceeded 20 m3/ha. This figure appears to represent a stand-level threshold value for the amount of dead wood, below which the persistence of threatened species becomes unlikely. Our results suggest that a significant increase in the amount of dead wood (e.g. by leaving large retention trees and even by killing trees) is needed in managed forests before they become suitable habitats for threatened polypores.  相似文献   
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An 18-week study was conducted to evaluate orthotopic osteochondral transplantation of the proximal femur in the dog. Eighteen dogs were divided into 3 groups of 6 each. The first group received autografts, the second received fresh allografts, and the third received grafts that had been frozen in a bone bank for 24–28 days. The grafts were fixed in position using dynamic compression plates. The grafted limbs were maintained in a sling and thus were nonfunctional and non-weight bearing throughout the 18-week study. Postoperatively the dogs were given oral tetracycline to assess osteo- cyte viability. The dogs were radiographed at 2–week intervals and 1 dog in each group was euthanatized every 3 weeks. The femurs were examined using standard histopathologic and fluorescent labeling techniques. All femoral heads were luxated by the 2nd postoperative week. The bones of all the femoral heads underwent avascular necrosis and degenerative changes were present in the transplanted cartilage by the 6th postoperative week. During the first 18 weeks following transplantation there was little radiographic and histologic difference among the 3 types of grafts regarding the nature and rate of bone healing. Based on the data obtained from techniques utilized in this study, the femoral head, neck, and articular cartilage did not survive, while the femoral diaphysis did survive the transplantation process. Different techniques may alter to some degree the results obtained.  相似文献   
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Testosterone concentrations in stallions showed a seasonal trend with peak concentrations in the spring (April and May in Britain) and lowest concentrations in the period from December to February. The effect on this pattern of changing the length of the photoperiod at the end of the normal breeding season (mid-summer's day) was studied in 2 experiments. In the first experiment artificial illumination was organised from 21 June to mimic the effect of transfer to a southern hemisphere spring and summer, that is short days becoming longer. The stallions had low concentrations of testosterone in February and high concentrations in April. Concentrations in July, August and September were extremely low with a return to high values in late November/early December. In the second experiment, illumination was maintained at the equivalent of a 16 1/2-hour day from 21 June to mid December. These stallions had high testosterone concentrations in April, after which they fell until August, later rising to a maximum in October. These results are discussed in relation to transfer of stallions between the northern and southern hemispheres.  相似文献   
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The Cloward technique for intervertebral fusion was utilized on 12 horses ranging from 3 months to 2 years of age. Of the 12 horses, 9 had been diagnosed as having equine cervical vertebral malformation (CVM) or "wobbles," and 3 were normal controls. A large hole was drilled from the ventral border of the vertebral bodies spanning the intervertebral disc and the vertebral end plates of the 2 articulating vertebrae. Frozen homologous bone dowels of slightly larger diameter from equine cadaver ilia were inserted in the holes. No adverse postoperative complication arose. Clinical improvement was seen in all horses with CVM. Three months postoperatively, partial or complete fusion was evident radiographically in 11 of the 12 horses. Necropsies were performed 3–6 months postoperatively to evaluate the quality of the fusion. Cadaver manipulation demonstrated reduced intervertebral movement at the operative site in all cases. The articulations of the equine cervical spine can be operatively fused by the Cloward technique, and surgically induced trauma is minimal. This technique can be used for stabilizing subluxations and may be applicable for treating fractures and osteolytic processes that have weakened vertebrae.  相似文献   
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Of 33 Escherichia coli strains isolated from canine urinary tract infections, 22 were haemolytic and 27 were classified into O serogroups, the most common being O4, O6, O2 and O83. P-fimbriated strains were haemolytic and belonged mainly to serogroups O4 and O6. Twenty-nine strains possessed type-1 fimbriae but only small numbers possessed S fimbriae, type-1C fimbriae, X adhesins or the aerobactin system. It is postulated that P fimbriae and haemolysin production contribute to bacterial virulence in canine pyelonephritis and cystitis.  相似文献   
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