湿帘-风机系统对北京地区发酵床猪舍冬夏季舍内热环境和空气质量影响研究

针对北京地区发酵床猪舍夏季热应激严重以及冬季通风不足的问题,试验在发酵床猪舍改造安装湿帘-风机负压通风降温系统,研究其对冬夏季节舍内热环境和空气质量的影响。结果表明:夏季在舍外日平均温度33.7℃时,与对照舍相比,妊娠试验舍和育肥试验舍内日平均温度分别低3.0℃和2.8℃(P0.05),有效环境温度(EET)分别低10.0℃和9.8℃(P0.01),猪只处于舒适区域而对照舍猪只处于热应激水平;在高温时刻14:00,妊娠试验舍内发酵床表面温度、母猪的呼吸频率和皮肤温度比妊娠对照舍分别低2.9℃、17.2次/min和1.6℃(P0.05)。冬季在气温较高时段开启小风量风机短时间通风期间,试验舍内温度降低0.4~1.3℃,NH_3和CO_2浓度及细菌总数降低幅度分别为58.1%~71.2%、49.6%~53.5%和21.9%~36.0%;当舍内相对湿度75%时机械通风后舍内PM_(2.5)和PM_(10)降低幅度分别为12.3%~20.0%和11.3%~24.9%,当舍内相对湿度75%时机械通风会增加舍内的粉尘浓度。因此,发酵床猪舍使用湿帘-风机系统既能满足夏季降温通风的需要,还能在冬季潮湿环境中改善空气质量,但冬季在适宜的相对湿度条件下应控制较小的气流速度。     

有缓冲间湿帘-风机系统对兔舍环境调控效果研究

为实现一套系统满足全年环境调控需求,试验选取两栋安装有"有缓冲间湿帘-风机系统"的兔舍,冬季其中一栋舍一台风机安装变频器,另一栋舍全为定速风机。结果表明,冬季定速风机常速间歇通风的兔舍导向板进风口的风速为1.8 m/s,进入舍内风速降至0.1m/s,每日首次开启风机10 min CO_2浓度降低67.2%,间歇通风每次温度平均降低0.8℃;使用变频风机低速持续通风的兔舍,导向板进风口风速0.2m/s,进入舍内风速降到了0.05m/s,开启风机CO_2浓度降低59.5%,温度降低0.3℃;两舍缓冲间预热能够分别提升气流温度2℃、1.4℃。夏季在舍外温度32.4~38.2℃时,舍内温度能维持在26℃左右,温度降幅为9.0℃,舍内温湿指数(THI)为25.9;外墙湿帘的降温效率为87.2%,内墙湿帘的降温效率为0。夏季缓冲间和进风口气流导向能够显著降低入舍风速(外墙湿帘过帘风速0.8m/s,导向板进风口风速1.9m/s,进入舍内风速0.3m/s),且舍内气流分布均匀。综合环境指标说明,有缓冲间的湿帘-风机纵向通风系统克服了冬夏季进风端风速大、温度低的弊端,但舍内隔墙上的湿帘无降温潜力,建议去掉第一缓冲间及内墙湿帘。     

东北地区冬季蛋鸡舍环境因素分布规律研究

为找到东北地区蛋鸡舍冬季保温和通风的平衡点,并将舍内环境条件控制在适合蛋鸡生长的范围内,试验对吉林省某蛋鸡舍温度、湿度、二氧化碳浓度、有害气体浓度和颗粒物浓度等环境因素进行连续监测,分析其分布规律和相互关系。结果显示:舍内平均温度22.1℃,平均相对湿度67%,不同监测点温湿度存在差异;平均氨气浓度为3.21 mg/m~3,其浓度和温度呈正相关,和相对湿度呈负相关;舍内颗粒物浓度分布情况为PM_1和PM_(2.5)浓度近风机端舍中远风机端,PM_(10)和TSP与之相反,即远风机端舍中近风机端;舍内CO_2平均浓度为8 576 mg/m~3,高于相关标准。基于CO_2浓度对试验鸡舍通风策略进行优化,得出该试验鸡舍最小通风量为0.56 m~3/h·kg,以及东北地区采用传送带清粪方式的蛋鸡舍应保证的冬季最小通风量为0.51～0.58 m~3/h·kg。     

冬季兔舍内温湿度及气体检测

为了了解在一定的通风和保温措施及粪污清理方式下,冬季兔舍内的主要环境参数水平,对室内笼养兔舍内的温湿度及氨气(NH_3)、硫化氢(H_2S)和氧气(O_2)含量进行了测定。一周检测结果表明,在没有采取供暖措施的条件下(夜间关闭门窗),舍内平均温度可以维持在4.3±1.22℃(早晨)和5.3±1.18℃(中午);舍内湿度平均79.9±6.03%(早晨)和47.0±19.0%(中午);早晨兔舍内的平均氨气浓度为1.9±0.73 ppm,中午未检出;早晨和中午舍内硫化氢气体未检出;早晨和中午的氧气含量均为20.2±0.06%(v/v)。根据检测结果,山东省室内笼养兔舍冬季在没有采取供暖措施的条件下,通过夜间关闭门窗,可使舍内温度维持在4℃以上,种兔群可以正常进行繁殖生产。     

不同通风方式对两层两列式网床肉鸭舍环境的影响

比较不同气候条件下不同通风方式对两层两列式网床鸭舍环境状况的影响。分别于寒冷(0～15℃),适宜(15～25℃)与炎热(25℃)气候时饲养肉鸭,每次采用自然、纵向、横向与混合4种通风方式,检测舍内温度、湿度、气压、风速、NH_3、CO_2、PM_(10)、PM_(2.5)、气载细菌总数、大肠菌群及葡萄球菌的浓度变化。结果表明:寒冷气候时,3种机械通风较自然通风均可显著降低鸭舍内湿度,其中横向通风未显著降低舍温;3种气候条件下,采用纵向与混合通风方式时鸭舍内NH_3、CO_2浓度均为最低,其中纵向通风改善颗粒物与气载微生物浓度效果最佳。4种通风方式NH_3、CO_2浓度分别为1.1～3.7 mg/m~3、911～2 607 mg/m~3,PM_(10)与PM_(2.5)浓度分别为234～551μg/m~3、166～361μg/m~3,气载细菌总数为5.18～5.78 lg(CFU/m~3),其中大肠菌群占细菌总数比例2%。此外,湿度与PM_(10)、PM_(2.5)间,PM_(10)与气载细菌总数间均呈显著正相关。纵向通风为两层两列式网床鸭舍最优通风模式。     

温湿度和有害气体对妊娠母猪繁殖性能的影响

本研究旨在探讨猪舍内温湿度、CO_2和NH_3浓度对妊娠母猪繁殖性能的影响。A组(重庆某猪场)、B组(湖南一种猪场)和C组(湖南二种猪场)3组妊娠母猪舍的结构基本一致,从2014年9月—2015年9月对3组妊娠母猪舍舍内温湿度、CO_2和NH_3浓度和妊娠母猪繁殖性能进行测定。结果表明:A、B组CO_2浓度、NH_3浓度均以冬季最高,显著高于夏季(P0.05),C组CO_2浓度、NH_3浓度均以冬季最高,显著高于秋季(P0.05);CO_2浓度和NH_3浓度呈正比例线性关系(r=0.555,P0.01),温度与CO_2浓度和NH_3浓度呈反比例线性关系(r=-0.341,P0.05)和(r=-0.653,P0.01),湿度与CO_2浓度(r=-0.514,P0.01)和NH_3浓度(r=-0.459,P0.01)的线性关系与温度保持相同趋势。研究表明,湖南地区和重庆地区最适合妊娠母猪分娩的季节是春季;妊娠母猪舍内CO_2浓度和NH_3浓度冬季最高,夏秋季较低;猪舍内有害气体浓度对活产仔数有一定影响。     

民用一体式热回收通风设备在空调降温兔舍内的环境调控和节能效果研究

试验通过研究夏季空调降温结合民用一体式热回收通风设备对兔舍内热环境、空气质量等指标变化的影响,分析民用一体式热回收通风设备在夏季降温兔舍中的通风节能效果。选择建筑形式、养殖密度相同的3栋有窗密闭式兔舍作为研究对象,试验兔舍1安装了4台民用一体式热回收通风设备和5台制冷空调;试验兔舍2安装了5台制冷空调,采取自然通风;对照舍无降温措施,采用自然通风;分别监测分析3栋兔舍的热环境指标、通风换气效果及设备热回收效率等。结果表明:空调降温舍的温度较无空调对照舍低6.3℃(P0.05),但其舍内二氧化碳及氨气浓度显著高于对照舍(P0.05)。试验兔舍1在一体式热回收通风设备运行期间与兔舍2的温度分别为26.3℃和26.8℃(P0.05),NH_3浓度分别为7.3mg/m~3和7.0mg/m~3(P0.05),CO_2浓度分别为0.126%和0.125%(P0.05)。与试验兔舍2相比,试验兔舍1运行一体式热回收通风设备对空调舍的温度、NH_3和CO_2浓度无显著影响,说明按民用通风需求匹配的一体式热回收通风设备在兔舍使用时存在新风量小,不能满足兔舍最小通风需求的问题,对舍内空气质量改善不明显。另外设备新风入口平均风速为14.3m/s,在风管管径不变的情况下至出口时风速衰减为5.6m/s,存在芯体与风机配比不当的问题。新风入口风速过大导致设备热回收效率较低,平均显热效率仅为31.2%,低于夏季节能标准(60%)。因此,民用一体式热回收通风设备因自身外形限制,与空调降温结合使用时通风节能效果不明显。若在畜舍中应用时,应打破民用一体机的模式,结合畜舍建筑特点及饲养密度,调整风机和芯体组合方式及参数配比。     

自然通风式哺乳猪舍环境及母猪繁殖性能季节性变化规律研究

为探究华南地区两广小花猪自然通风哺乳猪舍环境及母猪繁殖性能季节性的变化规律,本研究监测了华南地区不同季节1栋哺乳猪舍内外温湿度、二氧化碳浓度及母猪繁殖性能相关指标。结果表明：哺乳猪舍在春季、夏季和秋季平均温度高于27℃、平均相对湿度高于80%;冬季舍内平均温度为24.8℃,平均相对湿度低于80%;冬季舍内二氧化碳浓度最高,日平均值为2 058 mg/m³;夏季断奶窝仔猪数、仔猪断奶窝重和仔猪平均日增重低于其他3个季节(P<0.05),且随着温度和温湿指数的升高而降低(P<0.05)。综上,华南地区采用自然通风舍饲养的两广小花猪哺乳母猪的繁殖性能随舍内温度和温湿度指数的升高而降低。     

复合微生物除臭剂对冬季兔舍内空气环境质量的影响

兔舍内的氨气等废气对兔呼吸系统影响很大,使用复合微生物除臭剂可解决这一问题,但微生物群有其特定的适用条件和环境,在北方冬季寒冷地区复合微生物除臭剂是否有效是一个需要验证的问题。以河南省济源市阳光兔业科技有限公司为试验地点,进行了为期16 d的试验。选取兔数量、兔生长阶段、风机数量、建筑形式、饲养模式均相同的两栋兔舍,对两栋兔舍中的氨气(NH_4)、二氧化碳(CO_2)、温度、相对湿度、通风量进行检测。试验分为前后两部分进行:首先进行验证复合微生物除臭剂在冬季低温环境下是否有效和有效时长的试验,再进行复合微生物除臭剂对氨气的去除效果的试验。复合微生物除臭剂对兔舍内的氨气有去除效果(去除率为18.97%),喷洒1次的有效时长为2 d,但不能降低冬季兔舍内二氧化碳的浓度。持续使用复合微生物除臭剂能使兔舍内的氨气浓度显著降低(P0.05),平均去除率为14.37%,最高去除率为18.34%。复合微生物除臭剂对氨气的去除效果与兔舍内的温度、相对湿度和通风量存在线性关系,回归模型为:Y=-0.827X_1-1.006X_2+0.789X_3(X_1:日平均温度,X_2:相对湿度,X_3:通风量,Y:氨气去除率,R~2=0.82,P0.05)。     

湿帘降温在湿热地区兔舍中使用效果的研究及影响因素的分析

随着我国南方兔产业规模化快速发展,夏季高温对家兔生产的影响尤为突出。而湿帘降温系统在南方湿热地区兔舍的降温效果一直备受质疑。为了研究湿帘风机降温在我国南方湿热气候下兔舍中的使用效果,本试验选取了杭州、重庆两地研究湿帘风机降温结合纵向通风对兔舍热环境指标的改善程度。在舍外气温27~40℃的条件下,杭州和重庆兔场舍内平均温度分别为30.3℃和25.7℃,平均相对湿度分别为80.4%和82.9%,平均降温幅度分别为6.4℃和9.1℃,相对湿度分别上升为27.0%和36.9%,温湿指数THI分别为29.53和25.27,舍内风速分剐0.17 m/s和0.64 m/s。结果表明:湿帘降温在两地区湿热气候条件下都能取得良好的降温效果,有效地缓解家兔的热应激,保证其正常生产繁殖。分析降温效果的影响因素,纵向兔笼排列明显优于横向排列。此外,风机与湿帘的匹配及安装、风机-湿帘系统的运行时间对降温效果也有着显著的影响。     

An evaluation of apnea or spontaneous ventilation in early recovery following mechanical ventilation in the anesthetized horse

Objective To compare arterial oxygen and carbon dioxide tensions in apneic and spontaneously ventilating horses recovering from anesthesia. Study design Randomized clinical trial. Animal population Forty‐two healthy horses averaging 466 ± 106 kg and 6 ± 5 years of age. Methods Anesthetized horses undergoing a variety of surgical procedures and receiving positive pressure ventilation (IPPV) were divided into two equal groups. One group was allowed to return to spontaneous ventilation prior to disconnection from the anesthetic circuit (weaned). The other group remained apneic during transport to a recovery stall. Arterial blood gas data were collected at five time points: 20 minutes before moving to a recovery stall (t = ? 20); at the time the anesthetic circuit was disconncted (t = 0); at 3 and 5 minutes post‐disconnection (t = 3 and t = 5) and at the time of the first spontaneous breath (t = sv). The data were analyzed using an anova method for repeated measures and paired, two‐tailed t‐tests. Significance was assumed when p < 0.05. Results The apneic group took a mean of 5 minutes 18 seconds (± 135 seconds) before starting spontaneous ventilation. This group maintained significantly higher PaO₂ levels at intermediate time points (t = 0 and t = 3) but no difference was noted after 5 minutes. PaCO₂ levels were higher in the weaned group at time 0 minutes, returning to a comparable level to the apneic group at t = 3 minutes. Conclusions and clinical relevance Horses can survive a short period of apnea during transport from the surgery suite to recovery stall and may benefit from a reduced incidence of transient hypoxemia compared with spontaneously ventilating horses. This information has practical implications for the anesthetist evaluating the options for discontinuing IPPV when horses are moved to a recovery stall.     

Noninvasive ventilation in cats

Objective – The primary objective of this study was to assess the feasibility of noninvasive mechanical ventilation (NIV) in cats. The secondary objective was to determine whether cardiovascular parameters and anesthetic drug requirements associated with noninvasive ventilation differ from those associated with invasive ventilation. Design – Randomized, cross‐over design. Setting – A research laboratory in a veterinary teaching hospital. Animals – Eight healthy adult cats, 3 intact females and 5 intact males, weighing between 3 and 6 kg, were used. Interventions – Each cat was randomly assigned to NIV via nasal mask, or invasive ventilation using an endotracheal tube. Mechanical ventilation was performed for 6 hours. Anesthesia was provided using continuous infusions of propofol and butorphanol. After a minimum 9‐day washout period, the procedure was repeated using the alternate ventilation interface. Measurements and Main Results – Cardiovascular parameters (heart rate, rectal temperature, direct arterial blood pressure), arterial blood gases, drug requirements, sedation score, and ventilation parameters, were monitored throughout the procedures. These values were evaluated using ANCOVA for repeated measures. All cats were effectively ventilated using NIV. There were no significant differences in cardiovascular parameters, drug requirements, or sedation scores between groups. Although PaCO₂ values did not differ, PaO₂ values were significantly higher in the invasively ventilated group. Inspiratory tidal volumes were similar between groups, whereas expiratory tidal volumes were significantly lower in the NIV group. Inspiratory pressures were significantly higher in the NIV group. Respiratory frequency was significantly higher in the invasively ventilated group. Conclusions – NIV of cats is possible. However, currently it does not confer any cardiovascular benefit over invasive ventilation and drug requirements are similar. Use of a correctly fitted mask is essential for successful NIV as air leaks account for the observed discrepancy between inspiratory and expiratory volumes. Further investigation into this modality is warranted.     

Clinical use of positive-pressure ventilation in the horse

Positive-pressure ventilation is used to provide improved ventilatory support during anesthesia in the horse. Because of the horse's size and the physiologic changes it undergoes during anesthesia, however, the use of positive-pressure ventilation does not always provide the improvement seen in smaller species. Careful attention to respiratory rate, inspiratory pressure, and I:E ratio minimizes the negative aspect of IPPV on the cardiovascular system. The goal of future ventilatory techniques will be to improve oxygenation without cardiovascular compromise and to do so at a reasonable cost to the client.     

鸡舍冬季最小通风量的管理

即使在寒冷的冬季,也必须为鸡群提供适宜的通风。通风的目的在于供给鸡只足够的氧气,排出舍内的氨气、二氧化碳和水汽。虽然通风也同时增加了舍内热量的损耗,提高了燃料用量和饲养成本,但相对不良通风对鸡群的负面影响,这些成本的付出还是非常值得的。可在实际生产中,费用却总是显得那么难以回避,所以,冬季最小通风量的管理日渐引起关注。由于在一般的非封闭鸡舍内,通风的可控性非常低,这里仅对环境控制鸡舍进行探讨。     

Comparative ventilation and gas exchange in the horse and the cow

Ventilation and gas exchange were studied in healthy, adult horses and cows, two large species with different lung structures and different breathing patterns. The oxygen uptake (VO2), carbon dioxide output (VCO2), respiratory rate (fR), minute ventilation (VE), alveolar ventilation (VA), alveolar oxygen pressure (PAO2), and VE/VO2 ratio were higher in the cows, while the tidal volume (VT) and physiological dead space (VD) were larger in the horses. The arterial blood gases, alveolar-arterial oxygen pressure difference (PAO2-PaO2) and VD/VT ratio did not differ between the two species. The higher VO2 in the cows was most likely due to the energy cost of standing, and possibly to a higher cost of digestion. The higher VE, VA, VE/VO2 and PAO2 were most likely secondary to the increased VO2 and the slightly higher respiratory exchange ratio (R) in the cows. In contrast to hypotheses based on allometric equations, the PAO2 of horses and cows did not appear to differ from that of smaller mammals. The VD was larger than that predicted from allometric equations, and even though the VD/VT ratio (0.50) was lower than the previously reported values for horses and cows, it was significantly larger than the predicted weight-independent value of 0.36. Re-examination of the data used to derive the equation for VD raised questions as to the validity of this equation, and it is suggested that caution be exercised in the use of allometric equations for prediction.     

Topographic distribution of pulmonary ventilation and perfusion in the horse

The regional distribution of ventilation to perfusion ratios (VA/Q) in the lungs of 8 healthy standing Thoroughbred geldings (4.4 +/- 1.5 years, 465.7 +/- 46.6 kg) was studied, using steady-state inhalation and IV infusion of the radioactive gas krypton-81m. The VA/Q was uniformly distributed within a vertical lung strip centered over the 9th rib on the right side. Ventilation per unit of alveolar volume (V/VA) assessed from the clearance of inhaled radioactive gas in 5 horses increased from 0.49 +/- 0.13 (arbitrary units) in nondependent lung zones to 1.45 +/- 0.16 in dependent lung zones. Seemingly, a vertical gradient of pulmonary ventilation exists in the horse that is matched by a similar gradient of perfusion.     

通风换气在肉鸡生产中不容忽视

1肉鸡生长与生产特点 1．1肉鸡具有很高的生产性能主要表现为生长迅速、饲料报酬高、周转快。肉鸡在短短．56d内,平均体重即可从4．0g左右长到3000g以上,8周体重可增长70多倍,而此时的料肉比仅为2．1：1左右。