特殊大豆蛋白HP300对断奶仔猪生产性能影响的研究

选用４８头３０日龄断奶体重约７ｋｇ的杜长大三元杂交猪。随机分到２个处理组,每个处理３个重复,每个重复８头猪,对照组日粮为玉米－豆粕型日粮,试验组日粮在有等氨基酸水平基础上用ＨＰ３００替代普通豆粕,试验期２１ｄ。试验结果表明：断奶后第一周猪平均日增重以ＨＰ３００组为高,１７６．７ｇ／ｄ,比豆粕组高２３．１４％;第２周ＨＰ３００组猪的平均日增重显著高于豆粕组（Ｐ〈０．０５）,提高１６．３３％,但第３周     

Climate Change and North American Rangelands: Assessment of Mitigation and Adaptation Strategies

Recent climatic trends and climate model projections indicate that climate change will modify rangeland ecosystem functions and the services and livelihoods that they provision. Recent history has demonstrated that climatic variability has a strong influence on both ecological and social components of rangeland systems and that these systems possess substantial capacity to adapt to climatic variability. Specific objectives of this synthesis are to: 1) evaluate options to mitigate greenhouse gas emissions and future climate change; 2) survey actions that individuals, enterprises, and social organizations can use to adapt to climate change; and 3) assess options for system transformation when adaptation is no longer sufficient to contend with climate change. Mitigation for carbon sequestration does not appear economically viable, given the small and highly variable carbon dioxide fluxes of rangeland ecosystems and the high transaction costs that would be incurred. In contrast, adaptation strategies are numerous and provide a means to manage risks associated with climate change. Adaptation strategies are diverse, including altered risk perception by individuals, greater flexibility of production enterprises, and modifications to social organizations that emphasize climatic variability, rather than consistency. Many adaptations represent “no regrets” actions because their implementation can be justified without emphasis on pending climate change. Adaptations specific to livestock production systems can include flexible herd management, alternative livestock breeds or species, innovative pest management, modified enterprise structures, and geographic relocation. Social-ecological systems in which adaptation is insufficient to counter the adverse consequences of climate change might undergo transformative change to produce alternative ecosystem services, production enterprises, and livelihoods. The rangeland profession is in a pivotal position to provide leadership on this global challenge because it represents the intersection of management and scientific knowledge, includes diverse stakeholders who derive their livelihoods from rangelands, and interacts with organizations responsible for rangeland stewardship.     

Delivery of growth factors using gene therapy to enhance bone healing

OBJECTIVE: To review the delivery of growth factors using gene therapy for enhancing long-bone fracture healing. STUDY DESIGN: Literature review. METHODS: MEDLINE and CAB Abstracts literature search (1980-2004). RESULTS: Non-union and infected non-union are relatively common complications of long-bone fractures in human and veterinary patients. Growth factors are cytokines that regulate many cell functions important in fracture healing. Exogenous growth factors can be delivered to the fracture site as recombinant proteins or using gene therapy. Recombinant human bone morphogenetic protein-2 and -7 (rhBMP-2 and -7), in particular, enhance fracture healing in numerous experimental and clinical studies. Some limitations with use of recombinant proteins may be overcome by use of gene therapy. Gene therapy involves delivery of the growth factor gene to cells at the fracture site using a viral or non-viral vector. The gene is then expressed (protein synthesis) by cells at the fracture site. Delivery of the BMP gene to the fracture site using gene therapy has been evaluated in laboratory animal models of non-union, with favorable results and without complications. CONCLUSION: Delivery of growth factors, particularly members of BMP family, to the fracture site using gene therapy may be a method to enhance fracture healing. Use of this technology may improve the prognosis for patients with long-bone fractures. CLINICAL RELEVANCE: Clinical application of gene therapy could improve the prognosis for human and veterinary patients with long-bone fractures, but has not been evaluated clinically.     

DETECTION OF A LIVER TUMOR IN A BEAGLE DOG USING SINGLE PHOTON EMISSION COMPUTED TOMOGRAPHY

This case report describes the detection of a liver tumor in an 11–year-old female Beagle dog using single photon-emission computed tomography (SPECT). A mass was palpated in the cranial abdomen during removal of recurrent mammary tumors. A conventional nuclear medicine liver scan, following injection of ^99mTc-sulfur colloid, was equivocal. SPECT was then performed in a second procedure, using a simple system that rotated the dog before a gamma camera. Transverse plane images clearly showed a spheric space-occupying lesion, found at gross necropsy and confirmed histologically as a hepatoma. Discrete liver tumors may be detected more readily and their size determined more accurately using SPECT than with conventional nuclear medicine approaches.     

Open canalicular system of platelets in porcine stress syndrome

A study was undertaken to test whether a previously reported alteration in platelet morphology could be of predictive value for the detection of stress-susceptibility in pigs. Platelets from 20 normal pigs, nine pigs classified as stress-susceptible on the basis of their response to halothane challenge, and 11 siblings of halothane reactors belonging to two different breeds were subjected to electron microscopic examination. A quantitative analysis of electron micrographs, based on the extent of dilatation of the open canalicular system in platelets and the percentage of affected platelets, revealed that halothane reactor pigs could be distinguished from normal animals on the basis of their open canalicular system score. The discrete nature of the score categories in siblings indicates that platelet alteration may be an inherent component of the porcine stress syndrome and suggests that some of the false negatives in the halothane test may be identified as stress-susceptible on this criterion. Further studies involving a larger number of halothane reactors and siblings are needed to ascertain the consistency of the open canalicular system features and eventually, to develop a simple test system based on platelet alterations for the detection of stress-susceptibility in pigs.     

Corynebacterium pseudotuberculosis infections (Pigeon Fever) in horses in Western Colorado: An epidemiological investigation

Following reports of an increase in the number of Corynebacterium pseudotuberculosis infections in horses in the western counties of Colorado in 1997, an epidemiological assessment of the problem was conducted using a survey of premises with affected horses. No gender, age or breed predilections were found. Most diagnoses of disease were made in the summer or fall of 1997. Abscesses were reported to occur in various locations with a mean healing time of 77 days. A majority of premises owners reported potential contact of horses with sheep or goats. The days of lost use and treatment costs per case had a mean of 13 days and $139, respectively.