基于耕地质量成果的上海市耕地占补平衡运行机制研究

在对我国耕地占补平衡问题分析的基础上,结合占补平衡耕地质量内涵和上海市耕地质量成果应用条件分析,构建以数量平衡为前提的耕地质量占补平衡运行机制。该机制框架包括耕地质量评估和监测机制、占补平衡指标储备机制、占补平衡指标跨区使用机制和占补平衡实施经济保障机制等4个方面,以为完善耕地占补平衡制度提供依据。     

科尔沁草地的畜草平衡与草业发展途径的研究

根据实地调查和历年的统计资料，系统分析研究了科尔沁草地多年来草业发展速度落后于牲畜增长速度、畜草供需严重失衡的现状。结果表明，草地退化４５．９％，超载率达３６．１％。该地区发展草业的自然和社会经济条件优越，但必须采取以下措施才能达到畜草平衡的目的：加强合理利用和改良天然草地；发展人工饲草料基地，迅速增加种植畜牧业比例；大力发展秸秆及农副产品饲草料加工业     

全球气候变化对松嫩草原土壤水分和生产力影响的研究

本文首先模拟计算松嫩草原土壤水量平衡,并结合未来气候情景估算松嫩草原土壤水分的变化。最后,在土壤水分研究的基础上,初步评估全球气候变化对松嫩草原生产力的影响。     

Heart Rate Variability in Horses Engaged in Equine-Assisted Activities

Although there has been a recent surge in using horses to treat mental and emotional human health issues, the consequences of horse-assisted interventions on the stress response of horses have not been well documented. Assessment of the autonomic nervous system and its regulation of cardiovascular function has been used as an indicator of acute and chronic stress in human beings and horses. Heart rate variability (HRV) is a noninvasive measurement that has been used to assess autonomic nervous system regulation of cardiovascular function. There is evidence to suggest that several factors including the genotype, behavior, environment, temperament, and nutritional status of the horse play a key role in the large inter-individual variations in basal HRV. The present study determined whether 24-hour HRV recordings in horses currently working in equine-assisted therapy (EAT) differ from those previously shown in Thoroughbred horses. Findings from the present study found that in contrast to previous studies in Thoroughbred horses, diurnal and nocturnal low frequency and high frequency powers were not significantly different in horses that are currently engaged in EAT. Future studies are needed to determine the short- and long-term consequences of horses participating in EAT programs. Findings from this study will provide the basis for the development of a physiological/behavioral assessment criteria to determine the consequences of EAT on the well-being of horses as well as to help EAT Centers to improve the beneficial effects of EAT in human beings.     

带双负载运行的VIENNA整流器中点电压平衡控制

针对VIENNA整流器结构固有的中点电压波动问题,可以通过双负载结构中调整负载的大小来观察。文章分析了三相VIENNA整流器的工作原理,采用一种电压电流双环结构,空间矢量调制(SVPWM)方式控制运行。针对三电平结构固有中点电压波动问题,通过调节正负小矢量的作用时间,能够达到双负载在大小不同的情况下,直流电压稳定,中点电压平衡的效果,最后使用MATLAB/Simulink仿真证明了此方案的可行性。     

甘南牧区草畜供求动态变化与调控——以阿孜畜牧试验场为例

甘南牧区不仅是我国重要的畜牧业生产基地,而且是黄河上游的重要水源涵养地.过牧超载导致天然草地退化,严重影响牧区的可持续发展.以甘南州玛曲县的阿孜畜牧试验场为例,分析了2008和2009年天然草地的可食牧草产量、放牧家畜承载量等方面的动态变化.研究结果表明,2009年阿孜畜牧试验场产草量有所增加,月均产草量较2008年提...     

奶牛营养平衡与需要量

随着我国奶牛业的快速发展,奶牛对日粮营养平衡的要求越来越高,而正确理解奶牛的营养需要对制定营养平衡的日粮配方非常重要。本文主要从能量、蛋白质、纤维、矿物质和维生素方面探讨奶牛的适宜营养需要量。     

Influence of varying dietary electrolyte balance on broiler performance under tropical summer conditions

A 6‐week feeding trial was conducted to determine the effects of varying dietary electrolyte balance (DEB) on growth performance and physiological responses in broiler chicks reared during hot summer months (26.1–37.5 °C). The average minimum and maximum room temperatures recorded from 14 to 42 days of age were 26.1 and 37.5 °C, respectively, with relative humidity ranging from 51% to 55%. Five DEB treatments supplying 0, 50, 150, 250 and 350 (Na⁺+K⁺–Cl^?) mEq/kg of diet were prepared by adding NaHCO₃ and/or NH₄Cl to basal diet that contained 185 mEq/kg from 1 to 28 days and 172 mEq/kg from 29 to 42 days. These DEB diets were randomly offered to six experimental units of 20 chicks each. Improved 42‐day body weight gain (BWG), feed:gain (F:G) and reduced mortality was noted with DEB 50, 150 and 250 mEq/kg compared to DEB 0 and 350 mEq/kg. A quadratic effect of increasing DEB level was observed on BWG and F:G, whereas the effect was linear for feed intake, water intake and litter moisture. The DEB 50, 150 and 250 maintained better blood pH, pCO₂ and HCO₃ concentrations during acute heat stress periods than that of 0 and 350. The blood heterophil and lymphocyte percent as well as heterophil:lymphocyte were remained unaffected. The lowest DEB (0 mEq/kg) diet reduced the feed intake and promoted metabolic acidosis. At 350 mEq/kg DEB, water intake and metabolic alkalosis were promoted probably due to high levels of dietary NaHCO₃. The study concluded that overall better performance was recorded with DEB 50, 150 and 250 mEq/kg. These results indicated that single optimal DEB value could not be recommended to combat heat stress in broilers.     

河北省粮—饲平衡发展现状及对策建议

“粮改饲”政策推行以来,通过农业结构调整,实现了奶业振兴。伴随全球新冠肺炎疫情反复发生,粮食安全问题再次进入了公众视野,进而引发一个值得深思的问题：如何在保证粮食安全的前提下,实现草畜平衡,增加肉、蛋、奶市场供给,优化居民膳食营养结构。为此,以河北省为研究对象,深入分析粮食与饲草种植及市场供求。目前来看,河北省粮食种植面积在“红线”以上,饲草生产无法满足省内养殖业需求,同时,城乡居民对肉、蛋、奶的摄入仍未达到膳食营养标准。为优化农业种植结构及居民营养结构,提出推广新型种植模式、加强政策引导、创新生产技术等一系列措施,推动河北省粮—饲平衡发展。     

冷环境中解偶联蛋白对动物体温的调节作用

解偶联蛋白属线粒体内膜载体蛋白,存在动物体的棕色脂肪组织（brown adipose tissue,BAT）、白色脂肪组织（white adipose tissue,WAT）、骨胳肌以及各种器官中。这些组织器官是哺乳动物及禽类非颤抖产热（NST）及其它产热作用的主要点位,对动物的体温维持和能量平衡调节起重要作用。