规模化养鸡场粉尘的检测

鸡舍内粉尘浓度过高,会危害饲养员的健康和家禽的生产力,还会对周围环境造成污染。了解鸡舍内粉尘浓度空间变化情况,有助于进一步分析粉尘释放和变化规律,为开发更有效的除尘方法,试验测定了规模化养鸡场一年四季鸡舍门口和鸡舍中央的粉尘含量。结果表明,鸡舍中央位点全尘春季与冬季、秋季与冬季差异显著(P<0.05),夏季与冬季差异极显著(P<0.01);呼吸性粉尘PM10夏季与秋季差异显著(P<0.05),春季与冬季、秋季与冬季差异极显著(P<0.01);四季呼吸性粉尘PM10鸡舍中央位点与鸡舍门口差异不显著(P>0.05);全尘TSP鸡舍中央位点与鸡舍门口差异也不显著(P>0.05)。     

人工负离子对鸡舍空气环境净化作用研究

现代集约化、规模化畜牧生产存在舍内空气质量恶化问题,粉尘、有害气体及微生物蓄积,进而影响畜、禽健康和生产。笔者在舍内加装人工负离子发生装置,研究空气负离子对鸡舍中需氧菌总数、粉尘含量和氨气浓度的影响,探讨其在鸡舍空气净化中的应用。采用两栋完全相同的鸡舍,通过2个试验研究人工负离子对鸡舍空气环境的改善效果及有效作用时间。试验1,加装人工负离子发生装置鸡舍为试验组,无负离子发生装置鸡舍为对照组,在不同时间点采样测定;试验2,分别设置不同负离子发生功率,在负离子发生前、发生时及发生后不同时间采样测定。结果表明,在该试验条件下,人工负离子能显著降低鸡舍内需氧菌总数和粉尘含量(P0.05),而且具有明显的时间效应(P0.05),0.5μm以下粉尘含量不受负离子处理时间的影响(P0.05),1.0μm及以上粉尘含量随处理时间的延长明显降低(P0.01),空气负离子对鸡舍内氨气含量没有显著影响(P0.05);相对于低发生功率(32 W),43 W发生功率下空气负离子对鸡舍内粉尘和需氧菌清除效率更高,开启负离子发生装置30min后,可保持鸡舍内需氧菌总数30min和粉尘含量60min内处于明显降低状态(P0.05)。结果提示,空气负离子可用于改善鸡舍空气环境质量,有利于畜、禽健康生产。     

冬季六层层叠式笼养密闭式鸡舍环境质量测定与分析

试验旨在对六层层叠式笼养密闭式鸡舍冬季环境质量进行测定与分析,以期为蛋鸡层叠式笼养环境控制提供参考依据。以六层层叠式笼养密闭式鸡舍为研究对象,使用环境智能监控系统、粉尘采样器和测氧仪每天6∶00~8∶00、12∶00~14∶00和18∶00~20∶00对鸡舍水平和垂直方向上不同位置的环境质量参数(温度、相对湿度、光照强度、CO2浓度、风速、粉尘浓度和氧气含量)进行测定。结果表明,在采取侧窗进风、纵向通风的模式下,六层层叠式笼养密闭式鸡舍冬季平均温度、相对湿度和风速分别为19.18℃、58.75%和0.12 m/s,空气中平均二氧化碳浓度、粉尘浓度和氧气含量分别是2 477.22 mg/m3、3.27 mg/m3和20.23%,不同测定点之间环境质量存在差异。下层H0.6 m、H1.3 m和H1.9 m测定点的温度显著低于上层H3.1 m、H3.8 m和H4.4 m的温度(P0.05),上层的相对湿度显著低于下层(P0.05)。上层的光照强度低于下层的光照强度(P0.05),上层H3.1 m、H3.8 m和H4.4 m测定点的二氧化碳浓度和粉尘浓度显著高于下层(P0.05)。相关分析结果表明,冬季鸡舍内温度与相对湿度呈极显著负相关(P0.01),与二氧化碳浓度、氧气含量极显著正相关(P0.01);风速与温度、相对湿度和二氧化碳浓度呈负相关。     

AOS-80空气净化机对冬季鸡舍空气的净化作用

在有窗或无窗密闭式鸡舍中,舍内产生的有毒有害气体、微生物和粉尘对鸡的健康与生产性能有很大的影响。本研究选用AOS-80空气净化机,测定其对冬季蛋鸡舍空气的净化效果。选取尺寸、样式和饲养密度等完全相同的2栋蛋鸡舍做对比试验,2栋鸡舍通风采用自动控制装置。在试验鸡舍的屋架上按米字形均匀安装6台净化机,测定2栋鸡舍舍内有毒有害气体和空气细菌总数的浓度。结果表明:2栋鸡舍在适当通风条件下(使舍内温度维持在(15±0.1)℃,对照鸡舍和试验鸡舍的空气细菌总数平均浓度分别为33.3cfu/L和10.6cfu/L(P<0.01),净化机使之降低68.2%;NH3的平均浓度分别为1.71mg/m3和1.22mg/m(3P<0.01),净化机使之降低28.6%;H2S的平均浓度分别为0.670mg/m3和0.643mg/m3(P<0.05),净化机使之降低4.03%;蛋鸡平均周死亡率分别为0.997%和0.607%(P<0.01),净化机使之降低39.0%。本研究结果表明,舍内安装空气净化机能显著降低鸡舍空气细菌总数和有毒有害气体浓度,降低蛋鸡死亡率。     

智能化密闭商品肉鸡舍冬季生物气溶胶分布研究

为探究冬季智能化密闭商品肉鸡舍生物气溶胶分布规律,在山西中部某鸡舍均匀地设置了36个采样点,使用Anderson-6撞式空气微生物采样器,对白天(AM10∶00-PM3∶00)和夜间(PM10∶00-AM3∶00)两个时段的细菌和大肠杆菌的气溶胶粒径分布进行分析,并对细菌、大肠杆菌、金黄色葡萄球菌、霉菌等的气溶胶浓度分布以及气体和粉尘等的浓度进行监测。结果表明:细菌气溶胶主要存在于6级空气微生物采样器的Ⅰ、Ⅱ、Ⅲ级;主要刺激人体的上呼吸道;通风模式的不同对粉尘浓度的分布影响较大,对微生物气溶胶浓度分布影响不大;白天微生物气溶胶浓度分布与粉尘浓度分布不相关,夜间相关。     

冬季鸡舍内NH_3的空间分布规律

在冬季晴天和阴雨天及相应的温度和相对湿度条件下,对一大型机械化鸡舍内的NH3浓度空间分布和变化情况进行监测。本文主要研究和分析了晴天和阴雨天条件下在空间垂直方向上和不同水平面上的NH3分布变化规律。结果表明,在整栋纵向通风的鸡舍内存在NH3的低浓度区和高浓度区。在低浓度区晴天和阴雨条件下,NH3浓度随着距地面高度的增加而升高;在高浓度区,晴天条件下NH3浓度随着距地面高度的增加而升高,阴雨天条件下NH3浓度随着距地面高度的增加而降低。在逐渐深入鸡舍的水平方向上,NH3浓度在低浓度区缓慢升高,高浓度区急剧升高。     

鸡舍内粉尘危害以及减尘和除尘方法

正养鸡舍通常相对干燥,养鸡场常给鸡群饲喂干粉饲料,加之现代规模养鸡场鸡群饲养密度均较大,鸡群活动时皮肤和羽毛上的脱落物以及平养鸡垫料中释放的灰尘等更容易导致鸡舍内粉尘浓度增高,而鸡舍内粉尘浓度增高,不仅会直接对鸡群的呼吸道产生刺激,引起鸡群发生呼吸道炎症,而且附着在粉尘中的大量病原微生物,还会间接引发鸡群的传染性疾病流行。应高度     

垫料厚度对鸡舍氨气、二氧化碳和粉尘的影响

本试验旨在探讨垫料厚度对黄羽肉鸡舍内氨气、二氧化碳和粉尘的影响。试验选用1 600只21日龄苏禽黄鸡(公雏),随机分成4组,每组5个重复,每个重复80只鸡,分别饲养在结构、空间一致的独立鸡舍内(共20间),饲养密度为8只/m2。各组锯屑垫料厚度依次为4、8、12、16 cm,试验期从22~70日龄。结果表明:不同厚度垫料对各日龄鸡舍中粉尘含量有显著影响(P0.05),12 cm和16 cm垫料组35日龄鸡舍中氨气含量显著低于其他两组(P0.05),而粉尘含量显著高于其他两组(P0.05),12 cm垫料组70日龄鸡舍中氨气含量显著低于其他三组(P0.05),二氧化碳含量显著低于4 cm垫料组(P0.05)。由此可知,适当增加垫料厚度能够降低鸡舍氨气和二氧化碳含量,综合本试验结果,12 cm厚度锯屑垫料效果最佳。     

网上平养育雏舍不同位置环境参数变化和蛋鸡生长性能研究

试验通过对网上平养育雏鸡舍前端和后端环境指标持续监测,分析不同周龄不同位置的有害气体和粉尘分布规律。环境参数结果显示:网上平养育雏鸡舍后端的温度、氨气和粉尘浓度极显著高于前端(P0.01),前端湿度极显著高于后端(P0.01);后端二氧化碳浓度略高于前端(P0.05);随周龄增加和通风量加大,温度、氨气和二氧化碳浓度逐步降低,最后趋于稳定,湿度逐步升高,2~5周龄鸡舍粉尘浓度逐步升高,5周龄后急剧降低;除了鸡舍室内湿度低于标准要求外,温度、氨气、二氧化碳、粉尘等环境参数均符合养殖场空气质量标准。生产性能结果显示:蛋鸡体重随周龄增加呈线性增加,且鸡舍前后端鸡只体重差异不显著(P0.05);胫长在7周龄前呈线性增加,7周龄之后增加幅度放缓,且前后端差异不显著(P0.05)。     

南京郊区一次轻度污染过程中颗粒物数浓度垂直分布特征

近年来以PM2.5为代表的颗粒物污染备受社会各界关注,针对大气颗粒物污染,很多的研究大都集中质量浓度上,而且针对颗粒物的观测采样也重点放在市中心区,本文将目光放在大气颗粒物的数浓度上,选取南京市浦口区为采样点,利用日本加野麦克斯3887D型尘埃粒子计数器观测了生活区和风景区的颗粒物垂直分布。结果表明:生活区和风景区中,不同层次不同直径的颗粒物处于同一个量级,只是垂直分布特征存在差异。生活区中,直径较小(直径为0.3μm、0.5μm、1μm)的粒子数浓度随高度增加先增后减,而直径偏大(直径为3.0μm、5.0μm)的粒子其数浓度分布特征则恰好相反。在风景区,随着颗粒物直径的增大,颗粒物数浓度随高度减小的趋势越显著。     

Phase I evaluation of CCNU (lomustine) in tumor-bearing cats

1-(2-Chloroethyl)3-cyclohexyl-1-nitrosourea (CCNU) is an alkylating agent in the nitrosourea subclass. A prospective evaluation of CCNU was done to determine the maximally tolerated dosage of CCNU in tumor-bearing cats. Response data were obtained when available. Twenty-five cats were treated with CCNU at a dosage of 50-60 mg/m3 body surface area. Complete hematologic data were available for 13 cats. Neutropenia was the acute dose-limiting toxicity. The median neutrophil count at the nadir was 1,000 cells/microL (mean, 2,433 cells/microL; range, 0-9,694 cells/microL). The time of neutrophil nadir was variable, occurring 7-28 days after treatment, and counts sometimes did not return to normal for up to 14 days after the nadir. Based on these findings, a 6-week dosing interval and weekly hematologic monitoring after the 1st treatment with CCNU are recommended. The nadir of the platelet count may occur 14-21 days after treatment. The median platelet count at the nadir was 43,500 cells/microL. No gastrointestinal, renal, or hepatic toxicities were observed after a single CCNU treatment, and additional studies to evaluate the potential for cumulative toxicity should be performed. Five cats with lymphoma and 1 cat with mast cell tumor had measurable responses to CCNU. Phase II studies to evaluate antitumor activity should be completed with a dosing regimen of 50-60 mg/m3 every 6 weeks.     

Furosemide continuous rate infusion in the horse: evaluation of enhanced efficacy and reduced side effects

Continuous rate infusion (CRI) of furosemide in humans is considered superior to intermittent administration (IA). This study examined whether furosemide CRI, compared with IA, would increase diuretic efficacy with decreased fluid and electrolyte fluctuations and activation of the renin-angiotensin-aldosterone system (RAAS) in the horse. Five mares were used in a crossover-design study. During a 24-hour period, each horse received a total of 3 mg/kg furosemide by either CRI (0.12 mg/kg/h preceded by a loading dose of 0.12 mg/kg IV) or IA (1 mg/kg IV q8h). There was not a statistically significant difference in urine volume over 24 hours between methods; however, urine volume was significantly greater after CRI compared with IA during the first 8 hours ([median 25th percentile, 75th percentile]: 9.6 L [8.9, 14.4] for CRI versus 5.9 L [5.3, 6.0] for IA). CRI produced a more uniform urine flow, decreased fluctuations in plasma volume, and suppressed renal concentrating ability throughout the infusion period. Potassium, Ca, and Cl excretion was greater during CRI than IA (1,133 mmol [1.110, 1,229] versus 764 mmol [709, 904], 102.7 mmol [96.0, 117.2] versus 73.3 mmol [65.0, 73.5], and 1,776 mmol [1,657, 2.378] versus 1,596 mmol [1,457, 1,767], respectively). Elimination half-lives of furosemide were 1.35 and 0.47 hours for CRI and IA, respectively. The area under the excretion rate curve was 1,285.7 and 184.2 mL x mg/mL for CRI and IA, respectively. Furosemide CRI (0.12 mg/kg/h) for 8 hours, preceded by a loading dose (0.12 mg/kg), is recommended when profound diuresis is needed acutely in horses.     

Prevalence of gastric lesions in racing Alaskan sled dogs

Human and equine athletes are reported to have a high prevalence of gastric disease, and anecdotal evidence suggests a similar phenomenon applies to racing sled dogs. To investigate the prevalence of gastric disease in racing sled dogs, we conducted 2 gastroscopy studies on dogs competing in the annual Iditarod Sled Dog Race. A pilot study of dogs that were either dropped from the 2000 Iditarod Sled Dog Race because of illness or that finished the race indicated that, approximately 5 days after competing, 10 of 28 dogs (35%) had endoscopic evidence of gastric ulceration, erosion, or hemorrhage. The next year, an endoscopic study of 73 dogs participating in the 2001 Iditarod race was performed in order to evaluate a larger population of dogs. Data from 70 of these dogs could be used; 34 (48.5%) had ulceration, erosion, gastric hemorrhage, or some combination of these findings. When this group of 70 dogs was compared retrospectively to a control group of 87 dogs presented to the Texas A&M University (TAMU) Veterinary Medical Teaching Hospital, the Iditarod sled dogs had a significantly higher prevalence (P = .049) of gastric lesions. These findings suggest that, similar to athletes of other species, elite canine athletes have an increased prevalence of gastric disease compared to the canine population at large.     

Internal Parasites and Haematological Values in Cattle Slaughtered in Buea Subdivision of Cameroon

Tropical Animal Health and Production -     

The Epidemiology of Gastrointestinal Nematodes of Dairy Cattle in Central Kenya

The epidemiology of H. placei and of other gastrointestinal nematodes in yearling dairy cattle was examined on two farms in Kiambu District, central Kenya during each of 13 one-month periods from April 1993 to April 1994. On each farm, 32 newly weaned dairy calves were given a single dose of albendazole and then placed on experimental pastures. Twelve of the animals were designated for bi-monthly slaughter (n = 2) and analysis of worm population characteristics and 20 were designated for blood and faecal collection and for weighing. Two parasite-free tracer calves were grazed alongside the weaner calves each month throughout the study period and were also slaughtered for analysis of worm populations. Faecal egg counts, haematological and serum pepsinogen determinations, herbage larval counts, and animal live weight changes were recorded monthly. The study revealed that Haemonchus placei, Trichostrongylus axei, Cooperia spp. and Oesophagostomum radiatum were responsible for parasitic gastroenteritis and that H. placei was the predominant nematode present in the young cattle on both farms. Faecal egg counts from resident cattle and necropsy worm counts revealed that pasture larval levels were directly related to the amount of rainfall. The total worm burdens in the animals were highest during the rainy season (March–June and October–December) and lowest during the dry seasons (July–September and January–February). The very low recovery of immature larvae of H. placei from the tracer calves indicated that arrested development is not a feature of the life cycle of this parasite in central Kenya. The maintenance of the parasite population depended on continuous cycling of infection between the host and the pasture. The agroclimatic conditions of the study area were such that, in general, favourable weather conditions for the development and survival of the free-living stages of gastrointestinal nematodes existed all year round.     

Diversity of Ectoparasites in Sheep Flocks in Sa~o Paulo,Brazil

The occurrence of ectoparasites in sheep flocks is frequently reported but seldom quantified. Sheep production used to be a predominantly family activity in the state of Sa~o Paulo (Brazil), but it began to become a commercial activity in the past decade. Thus, information about the ectoparasites existing in sheep flocks has become necessary. The present data were obtained by means of questionnaires sent to all sheep breeders belonging to the `Associaça~o Paulista de Criadores de Ovinos' (ASPACO; Sa~o Paulo State Association of Sheep Breeders). Response reliability was tested by means of random visits paid to 10.6% of the respondents. Most of the properties (89.5%) reported the presence of one or more ectoparasites. Screw-worm (Cochliomyia hominivorax) was the most frequent ectoparasite (72.5%), followed by bot fly larvae (Dermatobia hominis, 45.0%), ticks (Amblyomma cajennense) and Boophilus microplus, 31.3%) and finally lice (Damalinia ovis, 13.8%). Combined infestations also occurred, the most common one being screw-worm with bot fly larvae (36.0%) followed by bot fly larvae with ticks (13.9%), screw-worm with ticks (9.3%), bot fly larvae with lice (6.9%), and ticks with lice (5.0%). The most common triple combination was screw-worm, bot fly larvae and ticks (12.8%). Breeds raised for meat or wool were attacked by bot fly larvae and ticks more often than other breeds. Lice were only absent from animals of indigenous breeds. The relationships among these ectoparasites are discussed in terms of sheep breeds, flock size, seasonality and the ectoparasitic combinations on the host.     

Chemotaxis of macrophage in inflammation

Our particular attention in this article was given to natural mediators for macrophages isolated from the sites of tissue injury. A number of chemotactic factors, which may satisfy many criteria making them acceptable as inflammatory leucocyte chemotactic factors, has been separated. Among them, our laboratory has isolated three macrophage (monocyte) chemotactic factors (MCF-a, -b and -c). Their purification, characterization and functional specificity are discussed.     

Evaluation of biohydrogenation rate of canola vs. soya bean seeds as unsaturated fatty acids sources for ruminants in situ

An experiment was conducted to study disappearance of C14 to C18 fatty acids, lag times and biohydrogenation (BH) rates of C18 fatty acids of ground soya bean and canola seeds in situ. Three ruminally fistulated Dallagh sheep were used to determine ruminal BH of unsaturated fatty acids (UFAs). Differences in the disappearance of fatty acids through the bags and lag times were observed between the oilseeds. We saw that the longer the incubation time of the oilseeds in the rumen, the lower the content of C18:2 and C18:3. Significantly higher lag times for both C18:2 and C18:3 were observed in ground canola compared to ground soya bean. BH rates of C18:2 and C18:3 fatty acids in soya bean were three times higher than those of canola. These results suggest that the fatty acid profile of fat source can affect the BH of UFAs by rumen micro‐organisms. So that UFAs of canola had higher ability to escape from ruminal BH. It seems that fatty acid profile of ruminant products is more affected by canola seed compared to soya bean seed.     

Serum biochemical values and mineral element contents of tissues in yaks

Serum biochemical values and the wet weight to dry weight ratios of tissues were determined in yaks in Shandan county of Gansu province. The liver, kidney, heart and muscle contents of seven elements in yaks were also analysed. Most serum biochemical values were similar to those of cattle, camels and sheep, but the calcium concentration was considerably above the normal range for other ruminants. The liver contained the highest concentrations of copper, manganese and cobalt and the kidney of selenium, iron and calcium.Abbreviations Alb albumin - ALT alanine aminotransferase - AST aspartate aminotransferase - BUN blood urea nitrogen - Chol cholesterol - Glob globulin - -GT -glutamyl transpeptidase - IP inorganic phosphorus - TP total protein