庆阳站持久高效草地农业优化模式

根据多年的技术资料和生产实际，采用线性规划法作为系统优化的基本方法，拟定了庆阳黄土高原试验站草地农业结构的优化模式。     

不同生长模型估计籽鹅早期体重发育规律及遗传参数

运用Logistic,Gompertz,VonBertalanfy和Cubic4种非线性生长模型对籽鹅1～1周龄的平均体重进行拟合,并分析生长发育规律及遗传参数。结果表明:虽然4个模型都能描述籽鹅的生长过程,拟合度均超过额0.99;但Logistic模型更符合实际饲养情况,能更好地预测体重,为最佳模型,其相应的体重极限参数A为2267.63g,调节参数B为16.27,瞬时相对生长率C为0.47,生长的拐点时间为6.48周龄,拐点体重为1136.81g。     

未来气候变化条件下青藏高原多年冻土区潜在植被类型面积预估

在青藏高原多年冻土区根据490个植被调查样点数据和3种遥感数据集的27个变量,利用决策树分类模型,模拟出4种代表性浓度路径情景下10个气候系统模式在2050年和2070年的青藏高原高寒草地类型(高寒沼泽草甸、高寒草甸、高寒草原、高寒荒漠和裸地)潜在分布结果。同时为保证数据分析的一致性,利用数据对当前高原草地类型也进行了反演。结果表明:相比当前高寒草地分布面积,预计在2050年和2070年裸地和高寒草甸面积微弱减少,高寒草原和高寒荒漠面积在微弱增加,高寒沼泽草甸面积变化不明显。结果在4种代表性浓度路径情景下的表现基本一致,研究不仅可以为高寒草地气候变化研究提供植被类型相关的数据支持,还可以为青藏高原多年冻土区碳循环的探讨提供部分的方法和理论依据。     

广西巴马小型猪动脉粥样硬化模型的制作

本试验旨在制作广西巴马小型猪动脉粥样硬化模型,初步判断猪发生动脉粥样硬化时的指数值,以期为今后建立相关模型提供依据。试验选取广西巴马小型猪试验组和对照组各10头,通过饲喂高脂高胆固醇饲料建立动脉粥样硬化模型,检测建模过程中血液生化指标,将动脉粥样硬化指数与血管切片作关联分析,初步拟定发生动脉粥样硬化时的指数值。屠宰后血管切片结果显示,试验组有2头广西巴马小型猪发生动脉粥样硬化,对照组均正常。2头广西巴马小型猪的血管切片结果与动脉粥样硬化指数进行关联分析后,初步拟定的动脉粥样硬化指数值在3.8以上,并持续3个月以上。     

Validating a Time Series of Annual Grass Percent Cover in the Sagebrush Ecosystem

We mapped yearly (2000–2016) estimates of annual grass percent cover for much of the sagebrush ecosystem of the western United States using remotely sensed, climate, and geophysical data in regression-tree models. Annual grasses senesce and cure by early summer and then become beds of fine fuel that easily ignite and spread fire through rangeland systems. Our annual maps estimate the extent of these fuels and can serve as a tool to assist land managers and scientists in understanding the ecosystem’s response to weather variations, disturbances, and management. Validating the time series of annual maps is important for determining the usefulness of the data. To validate these maps, we compare Bureau of Land Management Assessment Inventory and Monitoring (AIM) data to mapped estimates and use a leave-one-out spatial assessment technique that is effective for validating maps that cover broad geographical extents. We hypothesize that the time series of annual maps exhibits high spatiotemporal variability because precipitation is highly variable in arid and semiarid environments where sagebrush is native, and invasive annual grasses respond to precipitation. The remotely sensed data that help drive our regression-tree model effectively measures annual grasses’ response to precipitation. The mean absolute error (MAE) rate varied depending on the validation data and technique used for comparison. The AIM plot data and our maps had substantial spatial incongruence, but despite this, the MAE rate for the assessment equaled 12.62%. The leave-one-out accuracy assessment had an MAE of 8.43%. We quantified bias, and bias was more substantial at higher percent cover. These annual maps can help management identify actions that may alleviate the current cycle of invasive grasses because it enables the assessment of the variability of annual grass ? percent cover distribution through space and time, as part of dynamic systems rather than static systems.     

几种仔猪肠道损伤模型的建立及肠道损伤生物标志物的研究进展

肠道不仅是所有营养物质消化吸收的最终场所,也是动物体内最大的免疫器官,是机体防御体系的第一道屏障,维护动物肠道健康对保障养猪生产至关重要。肠道是机体应激反应的中心器官,各种应激因素致使肠道结构损伤与功能紊乱,从而导致仔猪健康不良与生长受阻。因此,建立稳定可靠的肠道损伤模型是研究仔猪肠道损伤机制及营养干预的关键,本文主要介绍了本实验室成功建立的几种仔猪肠道损伤模型,筛选了几种肠道功能紊乱的标志性分子,为猪和人类的肠道功能障碍研究及营养干预提供参考。     

从江县鲤爆发性死亡病例实验室诊断

2018年10月贵州省从江县某水产养殖专业合作社鲤爆发死亡,本研究对死亡病例进行了流行病学调查、病理学观察、寄生虫学检查、细菌分离鉴定和病毒PCR检测等诊断。结果显示:病鲤病变以鳃丝溃烂、体表出血、肛门红肿和眼球凹陷为主要特征,组织的主要病变是肾小球萎缩出血、肾小囊空腔、鳃丝肿胀粘连及上皮细胞脱落等;细菌分离培养可得到圆形凸起、表面光滑的灰白色菌落,经染色镜检、生理生化鉴定和16S rRNA基因测序分析,鉴定该分离菌为嗜水气单胞菌;PCR检测显示鲤浮肿病毒(Carp edema virus,CEV)为阳性,未检出鲤春病毒血症病毒(Spring viremia of carp virus,SVCV)和鲤疱疹病毒(Koi herpesvirus,KHV);显微镜观察亦未见到寄生虫虫体;分别取分离菌和鲤浮肿病毒阳性病例组织悬液进行人工感染试验,均可引起健康鲤发生死亡。上述结果表明,从江县鲤的死亡是嗜水气单胞菌和鲤浮肿病毒混合感染所致。     

Competition model for international comparisons of livestock

Interbull has been responsible for comparing dairy bulls across countries since the mid‐1980s. The current methodology is called MACE (multiple across country evaluations) which has been in use since 1995. Now that genomic data are being utilized in many countries, this has led to two serious problems. The first is that of preselection of young bulls such that the young animals are no longer a random sample of progeny from a sire by dam mating pair. Secondly, some countries are becoming less willing to share genomic data with Interbull. Both issues raise concern over the future of Interbull and international comparisons. This paper suggests a competition model as a potential replacement for MACE. The competition model makes pairwise comparisons between all pairs of bulls within a country and combines these differences across countries through bulls that are used in more than one country. Pedigree information is ignored as are all genomic data because bulls are treated as fixed. The model produces one international ranking of bulls averaging out any genotype by environment interactions which may exist. The competition model is illustrated by a small example. The limitations and advantages of the competition model are discussed.     

犬冠状病毒诊断技术研究进展

犬冠状病毒（canine coronavirus,CCoV）是导致犬胃肠道疾病的常见病原,与其他肠道病原共同感染时犬死亡率显著升高,严重影响养犬业的健康发展。快速、灵敏和特异的诊断技术对该病的防控起到至关重要的作用。除临床诊断外,常见的CCoV实验室诊断技术主要有病毒分离培养、电镜观察及血清学诊断技术,然而这些技术往往耗时长且工作量较大,分子诊断技术主要包括普通RT-PCR、实时荧光定量RT-PCR、纳米PCR等检测方法,这些诊断技术在准确性、敏感性及特异性上有极大提高,诊断效率也显著提高。近年来,随着分子免疫诊断技术与新型材料研发技术的迅速发展,新的检测方法应运而生,纳米金、核酸探针、芯片技术及纳米生物传感器等技术更加敏感、便捷、高效且都具有制备试剂盒的可能性,从而在诊断上具有简洁性和普适性。文章将针对CCoV的诊断技术进行全面综述,以期为CCoV诊断试剂的研发提供参考。     

兽医临床实例训练课程教学与考核模式的探索

兽医临床实例训练是安徽农业大学动物医学专业近几年新开设的一门实践课程。该课程以学校动物医院为实践平台,以提高学生的动手操作技能,增强临床实践能力,培养学生的临床思维能力和初步职业素质为目标,通过在教学过程中不断地实践和完善,探索出一套合理的、先进的教学与考核模式。该模式取得了明显的教学效果,为兽医临床实践教学改革提供了新思维和新方法。