外文翻译--空气温度和相对湿度对猪生理健康的影响.docx

空气温度和相对湿度对猪生理健康的影响介绍这项研究是关注在环境温度和湿度变化的影响，体温，呼吸频率，脉搏，和猪的其他因素。也有人希望知道在什么温度和湿度下猪是饲料转化是最高的。一些研究者已经研究，在极端的环境温度的影响下的猪的体温和呼吸频率较高。同样，几个工人研究高温和低温的饲料利用率的效果，临界温度也得到了重视。早在1883年谢尔顿（1883）报道，在冬季在无保护的开放环境下的猪比住在地下室的一个温暖的谷仓里的相似的猪需要更多的饲料大约25。在加拿大的渥太华，在冬季的几个月在小单育雏的母猪小屋的成本比常规育雏的母猪的房子要高出25（Grisdale，1904）。在一个相似幼猪的测试中，那些美联储内部获得更为迅速，所需饲料转化率较高，收益也是较低的。帕尔默（1917）曾报道过，由于太阳直射使大气温度和相对湿度百分比增加。加上处理和锻炼使猪的体温增加。Tangl（1912）报道，禁食猪体重大约100磅的临界温度为20-23摄氏度（68-74华氏度）。他还表明，体重超过200磅的猪的临界温度低于17摄氏度（63华氏度）。卡普斯蒂克和木材（1922）报道，300磅禁食猪的临界温度是21摄氏度（70华氏度）。戴顿（1929年）的工作证实了这些早期的发现，他的结果表明，临界温度为16摄氏度（61华氏度）左右。杰克逊（1938年）的一份报告表明，当大气温度平均为83度，猪会吃更多的饲料，它们还会一起打滚，比同类饲料猪投入的更经济，体重增加的更迅速。实验结果与讨论在我们的研究中使用的是绝缘测量9个由14英尺乘7英尺高的空调房间湿度的房间。通过腔室的空气运动是相对恒定的（每分钟20至30英尺）的空气温度和相对湿度可以控制在这些实验中的极限。纯种杜洛克新泽西州或波兰中国猪，或他们的第一代交叉，在这些试验中使用。他们在一个开放的环境下用口粮喂养，每天要进行两次这样的饲喂，如果他们有了的排泄物将会被清理：水会提供让他们进行自由的采食。在第一次试验中，它通过提供一个标准的浇水杯和一个普通水表。随后，它被发现更理想的使用在右手远角图1所示的浇水装置。这可以防止水飞溅。供给一个加仑的水箱，通过重力让水流从油箱进入（上可见，图1的后壁）。驯化的猪（一组两个，三个或四个）在70华氏度，通常至少有一个星期，而他们被训练的越来越习惯于周围的环境以及空气的温度，然后改变随意测试。整个测试期间空气温度尽可能恒定在一个固定的温度。测试期间，通常长为七天，偶尔会出现变化。直肠体温读数，脉冲使用听诊器和呼吸速率（每分钟呼吸），每天服用两次，在早晨喂奶前，或者在下午晚些时候。我们已经进行了六个不同的试验。一直在关注这四个变化温度和相对湿度的变化。空气温度的影响舍内的下限温度是华氏40度。在这些实验中使用的是由我们的冷却设备制冷来提供一个温度值，由同样的能够承受热环境相同的猪来进行试验。体温，呼吸和脉搏率。由于空气的温度上升至华氏40度，体温和呼吸速率（每分钟呼吸次数）增加（图2）。两个试验的结果（有代表性的）在图2中给出。他们说明了影响反应的猪体重的差异，在一个给定的高温度比重量超过150磅的猪体重在150磅的猪更舒适。重量更轻的动物可以保持在约115华氏度的温度下，而这是不可能的超过100华氏度采取较重的猪饲料消费，日增重，饲料利用率，和水的消耗。在图3中示出的增加饲料消耗上的空气的温度的效果。减少饲料消耗的空气的温度上升至40100华氏度，出现这种减少是在较高的温度下更快速。平均日增重也随气温的变化（图3）体重166至260磅的猪在60华氏度附近的上涨最为迅速，而重量更轻的动物，体重70至144英镑，上涨最为迅速的约75华氏度产生100磅的增益所需的饲料量是在最小增益的速率时，在最大（图3）。低于和高于这些温度下，约60华氏度的重量较重的猪和大约75华氏度为较轻的猪，饲料的利用率下降。耗水量是可变的。体重超过150斤的猪进行试验，水耗下降耗料类似的方式增加空气温度。在试验中，具有重量轻的猪，耗水量下降为空气的温度上升至40至90华氏度然而，从90至115F。耗水量增加。相对湿度的影响实验中，湿度是变量已经运行在90和96华氏度90华氏度，我们的数据表明，有没有太大的区别的响应猪体重超过200磅，相对湿度30和94的呼吸速率，不同的是在较高的湿度增加。应该提到的是在较高的湿度，这是不可能保持地板干燥。在华氏96度，相对湿度30，体重超过200磅的猪失去了重量，但长时间存活。当相对湿度提高到94，他们立即越来越心疼。在一个实验中在96华氏度的温度下，相对湿度逐渐折痕英寸8小时期间从30到94，和体温英寸折痕2.5华氏度，呼吸速率增加了一倍以上。这是不被视为建议持有的生猪在这些条件下，和相对湿度降低。在两小时内，相对湿度降低到58，在实验开始时，呼吸率和体温回到那个。水和空气运动蒸发冷却猪水的蒸发。在我们的第一次审判，重约250磅的猪被保存期限在90华氏度，在干燥的地板，相对湿度35。然后将温度保持不变，7天期间，一滴滴的水在地板上运行。用湿地板（约4.5加仑的水每小时流经地板）期内，收益率显着升高，呼吸率是大约30的干楼期间，体温的华氏度低。同样的比较，在100华氏度类似的差别。这是可能的空气温度提高到华氏115度与前地板上的水严重令人痛心的动物。在干燥的地板相同的动物在100华氏度心疼严重。由于水的蒸发的冷却效果是非常迅速的。运行与三个240磅猪一个实验在室温下100度F.所有106.8华氏度和150次每分钟的平均呼吸速率的平均体温困扰。四公升的水，在100华氏度，倾在地板上，使潮湿的区域。猪在水中立刻开始滚动。在20分钟内身体的温度分别平均降低1.0华氏度和呼吸率降低了50的。在90分钟的身体温度降低2.0华氏度和80的呼吸频率。在猪的皮肤温度比空气温度低的温度下，空气运动的影响是很有意义的。据推测由保迪（1945），扇是没有好处，在这些条件下的非出汗物种。凯利和联营公司（1948年）是由猪和环境温度的表面温度之间的关系。增加空气运动，潮湿的地板。在一个实验中，三个重周围250磅的猪潮湿的地板上，在约119华氏度的空气运动变化范围为每分钟20至30英尺，在生猪一级在腔室。风扇打开，增加空气运动估计平均每分钟175英尺，但是从100到250英尺不等。在30分钟内，降低了大约60的呼吸，体温平均减少大约2.5华氏度。在80分钟内，体温降低平均为3.0华氏度，当猪与空气运动以加速的速率上的湿地板。增加空气运动与干地板。相比之下，四头猪平均100斤左右干燥的地板上，在华氏113度开启风扇，增加空气流速和以前一样。首先，呼吸率和体温略有下降，因为它是不可能有地板完全干燥后，和猪略微潮湿的。随着干燥的地板和猪，呼吸率和体温再次升高，在启动时。经过5个小时的加速空气运动和干燥的地板，舒适的动物没有明显的好处。这种类型的实验已经重复了四平均187斤的猪，在华氏99度和四个平均236斤的猪没有明显的影响在100华氏度。猪的行为。由于空气的温度上升80华氏度以上的动物变得越来越懒惰，平躺在地板上，如图4所示。猪体重大约100磅重量轻仍然相当活跃，在80华氏度在高温，一个生猪撒尿时，一些其他的猪通常耽溺中的水分。这是真实的，粪便中的水分在一定程度上。猪上缴不时暴露自己潮湿的一面。在高温潮湿的地板上，猪的反应完全不同。躺在匍匐在其两侧，而是从一侧到另一侧，他们扔“非常活跃，他们给人的印象是试图保持他们的湿表面暴露。尸检结果。它需要具备尸检动物死于高温。因此，在第一个实验的第5天在100华氏度干燥的地板上，一手推车重达228磅死亡。在5天在100华氏度，此猪已经失去了18磅。期间死亡前，他的呼吸率一直适度的高，他的体温变化，从106.5到109.0度F.其他猪有体温高达108.7华氏度存活。不久后死亡，直肠温度为110.0华氏度在所有组织中不同程度的充血，尤其是在肋骨和肺部区域。挤塞肺血。讨论类似的工作已经报道由里根及联营公司（1938年，1939年），与奶牛。增加体温和呼吸频率（每分钟呼吸）和脉率增加空气温度下降非常相似奶牛（Regan和理查德森，1938），本文报告我们的条件下，猪。我们呼吸和体温的数据也印证了罗宾逊和李（1940年猪的工作，但在后期的工作中，他们报告心率增加，越来越多的环境温度。我们已经注意到在一些实验中有关冷却水临时增加脉率时，先放入水穷奢极侈，然后体温下降，由于水分蒸发，脉率下降。罗宾逊和Lee（1941）报道，在106华氏度猪的直肠温度是坐立不安。已经发现这仅是真实的时，潮湿的地板上的生猪的可能性表明，罗宾逊和李的工作和上述所报告的动物的皮肤的干燥度的差异所造成的差异。这将导致在皮肤温度的差异（Kelly和联营公司，1948）。此外，使用由Robinson和李（重约130磅的伯克郡）的猪被引入到一个房间已经在测试条件下为7个小时，而那些与我们的工作在房间平均约7天的期间和被驯化前的试验期间。Regan和米德（1939）报告说，奶牛减少水的消耗，提高空气的温度，在大多数情况下，我们的数据证实这些发现与猪。罗宾逊和李（1941）报告上伟大的冷却效果与水sousing的。我们的数据证实，并延长他们的研究结果。按照与罗宾逊和李（1941）华氏96度在提高我们的实验条件下，猪的体温在相对湿度高的效果观察。我们的数据表明这些实验猪的体重大约100磅的条件下，在更大程度上利用饲料和发胖，更迅速地在附近的75华氏度，而较重的猪，体重约200磅在60附近做的更好华氏度同意这些发现与文献报道的临界温度数据。据报道，空腹100磅的猪的临界温度由Tangl（1912）报道，以68-74华氏度，较重的猪是70华氏度（的卡普斯蒂克和木材，1922），6I华氏度（戴顿，1929年）和小于63华氏度（Tangl，1912）。总结不同的权重的猪被保存在温湿的时间平均为7天，温度范围从40到115华氏度相对恒定的相对湿度和空气流动的空间。由于空气的温度增加的体温和呼吸速率（每分钟呼吸次数）增加，脉率下降。由于空气的温度升高体温，呼吸频率和脉率的变化率增加。饲料消耗降低空气温度上升。这些实验的条件下，增益率是最大和产生100磅增益至少在平均温度约75华氏度猪体重166重量70至144磅，约60华氏度所需的饲料量至260磅。由于空气的温度超出这些平均值的增加或减少，增益率下降，降低利用食物。在96华氏度，相对湿度30至94的上升产生超过200磅重的猪较为窘迫，呼吸率和体温升高较快。水的蒸发冷却效果的深刻证明。在湿的猪增加空气运动的进一步的冷却效果已被证明有增加空气运动时，他们的皮肤温度低于环境的温度，在干燥的地板上生猪的效果缺乏。在这些条件下的猪的行为的一个动物在华氏100度死亡的尸检结果的讨论。THE EFFECTS OF AIR TEMPERATURE AND RELATIVE HUMIDITY ON THE PHYSIOLOGICAL WELL BEING OF SWINEIntroductionTHIS study is concerned with the effect of changes in environmental temperature and humidity on the body temperature, respiration rate, pulse rate, and other factors in swine. It was also desired to know at what temperature and at what humidity the pig was most efficient in utilizing the feed consumed.The effect of extreme environmental temperatures on the body temperature and respiratory rate of the pig has been studied by several investigators. Likewise, a few workers have studied the effect of high and low temperatures on rate of gain and utilization of feed. The critical temperature has also received some attention.Shelton (1883) reported as early as 1883 that it required about 25 percent more feed in winter for pigs kept in the open without protection than for similar pigs housed in the basement of a warm barn.In Ottawa, Canada, it cost 25 percent more to house brood sows during the winter months in small single brood cabins than in the regular brood sow house (Grisdale, 1904). In a similar test with young pigs, those fed inside gained more rapidly, and the feed required for their gains was lower.Body temperature increases due to the direct rays of the sun, to handling and exercise, and to increased atmospheric temperature and increased percentage relative humidity have been reported by Palmer (1917).Tangl (1912) reported that the critical temperature of fasting pigs weighing around 100 pounds was 20-23 degrees C. (68-74 degrees F.). He also showed that for hogs weighing over 200 pounds the critical temperature was less than 17 degrees C. (63 degrees F.). Capstick and Wood (1922) reported that the critical temperature of a 300 pound fasting hog was 21 degrees C. (70 degrees F.). Deightons (1929) work confirms these earlier findings, and his results indicate that the critical temperature is in the neighborhood of 16 degrees C. (61 degrees F.).A report by Jackson (1938) indicates that hogs having access to a hog wallow when the atmospheric temperature averaged 83 degrees F. ate more feed, gained more rapidly, and were more economical users of feed than similar pigs without access to wallows.Experimental Results and DiscussionThe psychrometric room used in our studies is an insulated airconditioned room measuring nine by fourteen feet by seven feet high. Air motion through the chamber is relatively constant (twenty to thirty feet per minute) and the air temperature and relative humidity can he controlled within the limits of these experiments. Figure 1 is a photograph of the psychrometric room while in operation.Purebred Duroc Jersey or Poland China swine, or their first generation cross, were used in these trials. They were fed the following ration in an open trough twice daily in such amounts as they would clean up without excessive wastage:Water was supplied ad libitum. In the first trial it was supplied in a standard cattle watering cup through an ordinary water meter. Subsequently it was found more satisfactory to use a watering device shown in the right hand far corner of figure 1. This prevented splashing. It was supplied from a tank (visible on rear wall, figure 1) graduated in gallons, by gravity flow.The pigs (in groups of two, three or four) were acclimated at 70 degrees F., usually for at least one week while they were being gentled and becoming accustomed to the surroundings. The air temperature was then changed to that desired for the test. The air temperature was held as constant as possible throughout the test period. Test periods, usually 7 days in length, were occasionally varied. Rectal body temperature readings, pulse (with the use of a stethoscope) and respiration rates (breaths per minute) were taken twice daily, before feeding in the morning and before feeding in the late afternoon.We have carried on six different trials. Four of these have been concerned with variation in temperature and two with variation in relative humidity.The Effect of Air TemperatureThe lower limit of temperature, 40 degrees F., used in these experiments was determined by the cooling capacity of our equipment; the upper limit, by the ability of the hogs to withstand heat.Body temperature, respiration and pulse rates. As the air temperature increased from 40 degrees F., the body temperature and respiration rate (breaths per minute) increased (figure 2). The results of two trials (which are representative) are given in figure 2. They illustrate the effect of difference in body weight on the reaction of the pigs; pigs weighing under 150 pounds were more comfortable at a given high temperature than the pigs weighing more than 150 pounds. The lighter weight animals could be kept at a temperature of approximately 115 degrees F., whereas it was not possible to take the heavier hogs much beyond 100 degrees F.Pulse rate decreased with increased room temperature (figure 2). Feed consumption, average daily gain, feed utilization, and water consumption. In figure 3 the effect of increasing air temperature on feed consumption is illustrated. Feed consumption decreased as the air temperature increased from 40 to 100 degrees F., and it appears this decrease is more rapid at higher temperatures. Average daily gain also varied with the changes in air temperature (figure 3.) Hogs weighing 166 to 260 pounds gained most rapidly in the neighborhood of 60 degrees F., while the lighter weight animals weighing 70 to 144 pounds gained most rapidly at approximately 75 degrees F.The amount of feed required to produce 100 pounds of gain was at a minimum when the rate of gain was at a maximum (figure 3). Both below and above these temperatures, approximately 60 degrees F. for the heavier weight pigs and about 75 degrees F. for the lighter pigs, utilization of feed declined.Water consumption was variable. In the three trials conducted with hogs weighing over 150 pounds, water consumption declined with increasing air temperature in a manner similar to feed consumption. In the trial with light weight pigs, water consumption declined as the air temperature increased from 40 to 90 degrees F. However, from 90 to 115 degrees F. water consumption increased.The Effect of Relative HumidityExperiments in which humidity was the variable have been run only at 90 and 96 degrees F. At 90 degrees F., our data indicate that there is not much difference in the response of hogs weighing over 200 pounds to relative humidities of 30 and 94 percent, except that the respiratory rate is increased at the higher humidity. It should be mentioned that at the higher humidity it was not possible to keep the floor dry. At 96 degrees F. and relative humidity of 30 percent, swine weighing over 200 pounds lost weight but survived for prolonged periods. When the relative humidity was increased to 94 percent, they were immediately increasingly distressed. In one experiment at a temperature of 96 degrees F., the relative humidity was gradually in. creased during 8 hours from 30 to 94 percent, and the body temperature in. creased 2.5 degrees F., the respiratory rate more than doubled. It was not deemed advisable to hold the hogs under these conditions, and the relative humidity was lowered. In two hours, the relative humidity was decreased to 58 percent, and the respiratory rate and body temperature were back to that at the start of the experiment.Cooling Swine by Evaporation of Water and Air MotionEvaporation of water. In our first trial, hogs weighing around 250 pounds were kept for a period at 90 degrees F. on a dry floor with relative humidity of 35 percent. Then the temperature was held constant and a trickle of water was run across the floor for a 7-day period. During the period with a wet floor (about 4.5 gallons of water per hour flowing across the floor), the rate of gain was markedly increased, the respiration rate was about 30 percent of that during the period on the dry floor, and the body temperature was L degrees F. lower. The same comparison was made at 100 degrees F. with similar differences. It was possible to raise the air temperature to 115 degrees F. with water on the floor before seriously distressing the animals. On a dry floor the same animals were distressed seriously at 100 degrees F.The cooling effect due to evaporation of water was very rapid. An experiment was run with three 240 pound hogs at a room temperature of 100 degrees F. All were distressed with an average body temperature of 106.8 degrees F. and an average respiratory rate of 150 breaths per minute. Four liters of water at 100 degrees F. were poured on the floor to make a wet area. The hogs began to roll in the water immediately. In twenty minutes the body temperatures were lowered an average of 1.0 degree F. and the respiratory rate lowered by 50 percent. In ninety minutes the body temperature was lowered by 2.0 degrees F. and the respiratory rate by 80 percent.The effect of air motion was of interest at temperatures where the hogs skin temperature was lower than the air temperature. It has been postulated by Brody (1945) that fanning is of no benefit to a non-sweating species under these conditions. The relationship between the surface temperature of swine and environmental temperature is given by Kelly and associates (1948).Increased air motion with a wet floor. In one experiment three hogs weighing around 250 pounds were on a wet floor at approximately 119 degrees F. Air motion in the chamber varied from 20 to 30 feet per minute at hog level. A fan was turned on, which increased the air motion to an estimated average of 175 feet per minute, but varying from 100 to 250 feet. In 30 minutes, the respiration was lowered by about 60 percent, and the body temperature was reduced about 2.5 degrees F. on the average. In 80 minutes, the body temperature was reduced an average of 3.0 degrees F., when the hogs were on the wet floor with an accelerated rate of air motion.Increased air motion with a dry floor. In contrast, four pigs averaging about 100 pounds were on a dry floor at 113 degrees F. The fan was turned on, increasing the air velocity as before. The respiratory rate and body temperature decreased slightly at first as it was not possible to have the floor completely dry, and the hogs were slightly damp. As the floor and hogs dried, the respiratory rate and body temperature increased again to that at the start. After five hours with the accelerated air motion and a dry floor there was no apparent benefit to the comfort of the animals. This type of experiment has been repeated with four hogs averaging 187 pounds at 99 degrees F. and four more hogs averaging 236 pounds at 100 degrees F. with no apparent effects.Swine behavior. As the air temperature rose above 80 degrees F. the animals became increasingly lazy and lay flat on the floor as shown in figure 4. The light weight pigs weighing around 100 pounds were still fairly active at 80 degrees F.At the high temperatures, when one hog urinated, some of the other hogs usually wallowed in the moisture. This was true to some extent of the moisture of the feces. The hogs turned over from time to time to expose their moist side. At high temperatures on a wet floor, the hogs reacted quite differently. Instead of lying prostrate on their sides, they tossed from side to side and were very active. They gave the impression of trying to keep their wet surface exposed.As the air temperature fell below 60 degrees F., there was an increased tendency for the swine to lie side by side, and practice so-called community heating (see figure 5).Autopsy findings. It was desired to have available for autopsy one animal that had died at high temperature. Thus in the first experiment on the 5th day at 100 degrees F. on a dry floor, one barrow weighing 228 pounds died. In the five days at 100 degrees F. this hog had lost 18 pounds. For the period previous to death, his respiratory rate had been moderately high and his body temperature varied from 106.5 to 109.0 degrees F. Other hogs have had body temperatures as high as 108.7 degrees F. and survived. Soon after death, the rectal temperature was 110.0 degrees F. There was hyperemia throughout all tissues in varying degrees, especially in the rib and lung areas. The lungs were congested with blood.DiscussionSimilar work has been reported by Regan and associates (1938, 1939), with dairy cattle. The increase in body temperature and respiratory rate (breaths per minute) and decrease in pulse rate with increasing air temperature were very similar in dairy cattle (Regan and Richardson, 1938) to those in swine under our conditions reported herein. Our data concerning respiration and body temperature also confirms the work of Robinson and Lee (1940 with swine, but in the latter work they reported an increase in pulse rate with increasing environmental temperature. In some of the experiments concerned with cooling with water we have noted temporary increases in pulse rate when water was first placed on the hog. Then as the body temperature decreased due to water evaporation the pulse rate decreased. Robinson and Lee (1941) reported that at rectal temperatures of 106 degrees F. hogs are restless. We have found this only to be true when the hogs were on a wet floor. The possibility suggests itself that differences between the work of Robinson and Lee and that reported above ar