自然通风畜舍之间污染物扩散的数值模拟研究

研究利用流体动力学(CFD)模拟方法研究了自然通风情况下两畜舍间及其内部的气流分布和污染物分布;采用湍流标准k-ε模型及组分输运模型,分析不同畜舍间距(1、2、3倍屋脊高H)和不同污染物释放位置(上风向舍内和下风向舍内)对畜舍自然通风空气流动模式和污染物分布的影响。结果表明:下风向舍释放的污染物有可能到达上风向舍,但其量极小,可以合理忽略;自上风向舍释放污染物时,3H间距时下风向舍内污染物浓度与2H间距时相似,是1H间距时的65%,因此选择2倍脊高作为畜舍防疫隔离距离既有效又经济。     

畜舍的朝向与采光

畜舍的朝向与采光会对畜舍的环境造成一定程度的影响,进而影响所饲养牲畜的生长,具有极其重要的作用,这就要求相关人员必须对其给予足够的重视。笔者主要结合朝阳县的实际情况,对畜舍的朝向与采光进行一系列的研究分析。在此基础上,对于畜舍的修建给予一些建议,为相关牲畜提供良好的成长环境。     

对畜舍气候的卫生标准的探讨

畜舍气候是指畜舍内的气象状况,主要包括的温度、湿度、气流及光照等。因为家畜的生活与生产活动绝大部分在畜舍中进行,所以畜舍小气候与家畜的关系十分密切。而且与大气相比虽然差异较大,但容易控制和改造。本文就畜舍气候的卫生标准做一探讨。     

测定位置与管理因素对猪舍中氨气测量值的影响

对畜舍环境中氨气浓度的测定是评价畜舍环境或评价氨的控制技术的常用方法。本试验研究了测定位置与管理因素对猪舍中氨气测量值的影响,并对温度、湿度对畜舍中氨气浓度进行了回归分析研究。结果表明：氨气值随测定高度增加减少,通风、清粪对氨气浓度的影响极显著;温度和湿度明显影响氨的浓度,猪舍中氨气与温度（T）、相对湿度（RH）的回归方程为YNH3=0．560T＋4．602RH-8．559（P〈0．01）。     

测定位置与管理因素对猪舍中氨气测量值的影响

对畜舍环境中氨气浓度的测定是评价畜舍环境或评价氨的控制技术的常用方法。本试验研究了测定位置与管理因素对猪舍中氨气测量值的影响,并对温度、湿度对畜舍中氨气浓度进行了回归分析研究。结果表明：氨气值随测定高度增加减少,通风、清粪对氨气浓度的影响极显著;温度和湿度明显影响氨的浓度,猪舍中氨气与温度（T）、相对湿度（RH）的回归方程为YNH3=0．560T＋4．602RH-8．559（P〈0．01）。     

养殖场畜舍空气环境质量要求

<正>养殖场畜舍环境主要是指畜舍内的空气环境。在自然条件下,畜舍内空气环境与自然界差异较大,舍内空气的温度、湿度常比舍外高,灰尘和有害气体也很多,风速和光照则低于舍外。畜舍的作用在于给家畜创造良好的空气环境,减弱大气不良因素的影响,因此建造适宜的畜舍类型以及控制其它影响因素,对促进家畜健康和生产力的提高,都十分重要。1畜舍的基本结构和作用畜舍各部分结构组成包括:屋顶及顶棚、墙、地板、地基、门窗等。其中屋顶和外墙组成畜舍外     

北方寒区畜舍防寒保暖技术及发展前景

目前国内外科技工作者经过多年的研究,已经将许多先进的科学技术应用到提高畜舍的防寒保温效果上来,并取得了非常喜人的成效.下面介绍几种应用在畜舍防寒保温性能中的技术及方法.     

肉牛场生物安全集成技术的研究与推广

为研究与推广生物安全集成技术在肉牛场的应用,综合运用肉牛饲养学、预防兽医学、动物疫病流行病学、动物传染病学、动物环境卫生与畜舍建筑学等理论,对肉牛场的科学选址、肉牛场的生物安全设计与建造、肉牛隔离检疫等10个关键环节进行了研究,总结制定了肉牛场生物安全集成技术10项。     

电子计算机在畜牧业中的应用

在畜牧业中,从育种、饲养、管理到畜舍设计等方面都可使用电子计算机。 1.电子计算机在家畜、家禽育种中的应用家畜育种需要应用群体遗传学或统计遗传学的原理和方法,电子计算机对于分析家畜的遗传行为和选配家畜的工作可以给予很大的帮助。通过运算与分析,可以预测后代的性能。根据这些结果进行选择,然后将选择的结果加上补充或修正资料,输入电子计算机进行分     

沙漠沿线暖棚畜舍设计建设评价

沙漠沿线风大、冬季寒冷,是制约设施畜牧业发展的重要因素。利用新型透光保温材料-万通板,在暖棚畜舍采光处扣棚,即可采光保温,也可经久耐用。本文就暖棚畜舍建设、万通板的安装设计以及改造后暖棚畜舍的保温效果做了总结和评价。认为利用万通板扣棚改进后的暖棚畜舍建设,不仅为沙漠沿线风沙大的甘肃、新疆、内蒙、宁夏等地修建暖棚畜舍提供技术支持,也为西部地区冬季风大、寒冷地域提供了技术参考。     

Societal expectations of livestock farming in relation to environmental effects in Europe

The potential environmental effects of livestock farming are mainly associated with intensification of poultry, pig and dairy cow production systems. The major impacts are mainly caused by housing of livestock, which can lead to air and water pollution associated with nitrogen and phosphorus emissions and losses from manure. European countries regulate the potential for these types of pollution through a number of mechanisms, which have received wide public acceptance. In grazing systems, nitrogen pollution, associated with the use of nitrogen fertilizer, is also the subject of legislation. Perhaps because of this regulatory approach, surveys of the public have found that human food quality and animal welfare are more important issues than effects on air and water quality when considering livestock systems.Variation in stocking rates of grazing ruminants can change the structure and composition of pastures with potential impacts on biodiversity and the production of methane, a greenhouse gas. In European countries, maximum stocking rates have been set to reduce these impacts. Surveys of the European public have suggested that they are willing to pay for the mitigation of these environmental effects but that they also value strongly the cultural component of grazed livestock systems. There are few underlying concepts about how society views the environmental impacts of livestock systems. These are used to conclude that current attitudes are likely to prevail in the next decade.     

畜禽场氨减排技术研究进展

近年来,随着规模化养殖业的迅速发展,畜禽饲养密度不断增大,导致养殖业氨排放量大幅上升,严重影响畜禽健康及其生产性能,同时造成大气污染,因此开展养殖场氨减排技术研究对于畜禽健康、产品安全和环境改善均具有重要意义。着眼于畜禽内源氨营养调控、畜禽舍内原位净化和粪污处理过程三个重点环节,综述了多种氨减排技术,包括从源头的饲料优化、粪便除臭剂使用、舍内空气净化及粪污处理过程中的固液分离、表面覆盖等技术,对于养殖业氨减排具有一定参考意义。     

舍内关键环境因子对畜禽健康影响的研究进展

养殖环境是影响畜禽健康和生长的重要因素,饲养密度过高易导致畜禽舍内局部空气温湿度、空气环境颗粒物和有害气体浓度升高,畜禽易出现热应激和呼吸道疾病,降低生长性能。明确养殖不利环境因素对畜禽健康的影响和机制,对于通过改善养殖环境提高畜禽健康状况具有重要意义。文章针对畜禽舍高温、颗粒物和有害气体等关键环境因子对畜禽生长性能、繁殖性能、免疫性能和呼吸道健康等的影响进行综述,针对存在问题提出建议,旨在为我国畜禽养殖产业转型升级与可持续发展提供理论依据。     

Livestock–wildlife joint land use in dry lands of Kenya: A case study of the Lolldaiga Hills ranch

This study aimed to examine livestock–wildlife interactions at the micro level and to quantify how resources are shared in joint land use by comparing the monitoring records collected on the Lolldaiga Hills ranch in Laikipia, Kenya from 1990s onwards. Livestock and wildlife distributions together with existing water points were geo‐referenced; by air and road census total animal biomass densities were estimated. Through 38‐h observation at a water point, livestock–wildlife interaction was recorded. During this period, water decline has been identified as an acute factor for farming and ranching. It was found that distributions of livestock and wildlife were related to water and pasture availability during the severe drought in 2009. Although there is seasonality in densities of both livestock and wildlife populations, results of air census indicated that the stable resident populations of wildlife have resided on the ranch. In this paper, we describe how livestock and wildlife interact at a water point and on pastures on the ranch in terms of biomass density. Such resources shared at different times need to be investigated further as a key factor to improve productivity of livestock–wildlife joint land use.     

"Exposure to isoflurane vapours in operating theatres: A comparative study"

Pollution and chronic exposure to waste anaesthetic gases may be a serious problem for operating theatre personnel. The authors reported the air contamination levels of isoflurane in the operating and preparation rooms at Clinica Chiruryica Veterinaria (University of Milan) and compared them with those of methoxyflurane, halothane and enflurane, previously detected in the sailie rooms.     

畜禽养殖舍氨气排放特性及减排技术研究进展

畜禽养殖舍是重要的氨气(NH_3)排放源,了解畜禽舍NH_3排放特性及其减排措施对于畜禽健康生产和环境健康均具有重要意义。本文综述了国内外有关猪、鸡、牛3种主要畜禽养殖舍内的NH_3排放特性,对于不同畜禽舍内影响其NH_3排放的关键影响因素进行了探讨,并对3种畜禽舍的NH_3排放因子进行了比较,总结了当前广泛采用的各类畜禽舍内的NH_3减排技术,包括从源头的饲料优化、排泄后粪便添加剂使用、舍内空气净化处理以及外排空气过滤装置等,构建了全方位的畜禽舍NH_3减排措施体系,对于了解畜禽舍NH_3排放特性,以及减排措施的选择具有重要参考意义。     

氨气影响动物健康和生产性能的机理

随着畜禽养殖数量和规模不断扩大,养殖环境趋于恶化。畜禽对空气质量敏感,空气质量与发病率直接相关。氨气（NH₃）是影响动物健康及生产最主要的环境有害气体之一。动物长期暴露于氨气中会诱发呼吸系统疾病,引起神经功能障碍,降低生殖能力和生长能力。本文总结了氨气影响动物健康和生产性能的机制。     

Rangeland Livestock Production in Relation to Climate and Vegetation Trends in New Mexico

A large statewide historical database involving livestock numbers, vegetation cover, precipitation, air temperature, and drought frequency and severity allowed us to explore relationships between climate and rangeland livestock grazing levels and livestock productivity from 1920 to 2017. Trends in vegetation cover and livestock grazing levels from 1984 to 2017 were also explored. Our climate time series was divided into two periods, 1920 ? 1975 and 1976 ? 2017, based on an apparent accelerated increase in mean annual air temperatures that began in the mid-1970s. Both mean annual precipitation (MAP) and mean annual air temperature (MAT) differed (P ≤ 0.05) between the two periods. MAP and MAT were 9.6% and 3.4% higher in period 2 compared with period 1, respectively. From the 1920s to 2010s the livestock grazing level and weaned calf numbers fell 30% and 40%, respectively, despite a significant increase in MAP. Long-term declines in livestock grazing levels and in weaned calf numbers were significantly (P ≤ 0.05) correlated with increasing MAT (r = ? 0.34 and r = ? 0.43, respectively). No long-term trends (1984–2017) in woody or perennial herbaceous cover were detected at the level of the entire state of New Mexico. Woody plant cover dynamics for New Mexico were not related to livestock grazing levels. However, at the county level we detected a 2% increase in woody plant cover coupled with a 9% decrease in cattle animal units between 2000 and 2002 and 2015 and 2017 for 19 select counties well distributed across New Mexico. Increases in woody plant cover varied greatly among counties and were higher for eastern than western New Mexico. Both global and New Mexico data show the climate warming trend is accelerating. Our findings have relevance to several other parts of the world because New Mexico occurs at midlatitude, has varied topography and climatic conditions, and several different range vegetation types.     

空间电场对冬春季畜舍温室气体的净化效果

[目的] 探讨空间电场对冬春季畜舍内温室气体的净化效果以及对舍内温湿度的影响。[方法] 在畜舍内安装空间电场净化设备和温湿度监测仪,舍内外均设置3个取气点,每个取气点分0 m、0.5 m、1.0 m和1.5 m 4个采集高度,系统监测冬春季畜舍温室气体浓度以及温湿度变化情况。[结果] 空间电场显著（P<0.05或P<0.000 1）降低了冬春季畜舍内CH₄、NH₃和CO₂气体的浓度,降低幅度分别可达39.8%、26.3%和24.0%。空间电场可显著（P<0.05）降低冬季舍内20：00—8：00和12：00—15：00的环境湿度,分别降低了4.5%和15.3%。春季湿度在9：00—17：00降低了31.9%（P<0.05）。[结论] 空间电场可有效地降低冬春季畜舍内CH₄、NH₃和CO₂气体浓度,同时显著降低畜舍内不同时间段的环境湿度。     

The relationship between production and infertility in dairy cows

Extract

Each year increasing numbers of livestock are transported by land, rail, sea and air, vet documented observation of the behaviour of stock during transit has seldom been recorded. The trans-shipment of weaner calves between the North and South Islands of New Zealand provided an opportunity to gather information on conditions of travel and general adaptation to a journey of 1600 kilometres by road and air.