造成猪热应激的原因与防治

<正>猪是怕热的家畜,由于炎热夏季的到来,对猪只的科学饲养管理显得尤为重要。热应激是指处于高温环境中的动物机体对热环境所做的非特异性生理反应的总和。猪生活的最适温度为:初生仔猪27℃~29℃,断奶仔猪21℃~24℃,生长肥猪15℃~25℃,哺乳母猪16℃~18℃。在最适环境温度范围内时,猪机体产热和散热保持平衡,饲料利用率高,抗病力强。超过最适温度范围时,猪     

从热应激看夏季疾病防控

<正>热应激是指处于高温环境温度中的动物机体对热环境提出的任何要求所做的非特异性的生理反应的总和。猪生活的最适温度:初生仔猪27℃--29℃;断奶仔猪21℃--24℃;生长肥猪15℃--25℃;哺乳母猪16℃--18℃。     

规模化猪场夏季饲养管理及保健要点

夏季气温高,给猪场生产带来不少问题,对规模化猪场的影响更为突出,如热应激、采食量下降、增重减慢、繁殖障碍等,本文拟对高温季节猪场的饲养管理及保健问题进行初步探讨。1猪群热应激的表现妊娠母猪的最适温度为22℃～25℃,哺乳母猪为15℃～18℃,公猪为15℃～18℃,哺乳仔猪为28℃～32℃,保育猪为24℃～28℃,肉猪为18℃～21℃。当环境温度高于32℃时,猪群则出现热应激。1.1公猪性欲降低、精液品质下降。一般认为公猪睾丸造精机能产生障碍的极限温度为30℃,相对湿度为85%,遭受高温的公猪精液品质降低,并且会导致其受应激过后4～6周繁殖力较低…     

夏季猪热应激及防治

猪属恒温动物,皮下脂肪厚,汗腺不发达,体内热能散发较慢,因此猪很不耐热。饲养实践证明,猪生长发育需要的适宜温度随体重和年龄增加而下降,初生仔猪为27～29℃,断奶仔猪为21～24℃,生长育肥猪为15～25℃,产仔和哺乳母猪为16～18℃。在最佳环境温度内,猪的产热和散热维持动态平衡,饲料利用率高,生长速度快,抗病率强。当猪的产热大于散热,体温升高,则容易发生热应激反应。炎热的夏季即将来临,做好猪的热应激预防工作格外重要。     

猪舍内夏季降温技术分析

猪是恒温动物,皮下脂肪较厚,汗腺不发达,夏季高温环境会对猪的生产性能产生很大的影响。生产实践证明,当环境温度达到25℃以上时,如不采取降温措施,猪群(除哺乳仔猪外)将会处于热应激状态,猪的生产性能受到很大影响:母猪受胎率下降,产仔数减少,哺乳母猪采食量下降,泌乳量减少,生长育肥猪饲料报酬和日增重下降等。因此在夏季高温季节对猪舍内环境温度要进行调控,可提高猪的生产性能。     

夏季哺乳母猪的饲养与管理

集约化养猪场中夏季哺乳母猪饲养与管理水平的高低直接关系到哺乳仔猪成活率,同时也关系到哺乳仔猪的整齐度及断奶体重。笔者将自己在生产实践中积累的经验和同行探讨。1哺乳母猪的管理1.1防暑降温哺乳母猪最适宜的环境温度为15～20℃之间,而夏季环境温度高达30～40℃,且昼夜温差小。这样的温度会直接影响哺乳母猪的生产性能,部分母猪还会因为热应激导致死亡。所以,必须采取有效的措施降低分娩舍内的温度,     

猪热应激的危害及防控措施

夏季,高温对猪群应激较大,给养猪业带来不小的影响。现就夏季猪热应激的危害以及防控的措施,浅谈以下几点。1热应激对猪的危害夏季气温高、湿度大,猪容易产生热应激,导致猪群采食量普遍下降,公猪性欲下降,精子活力差;母猪分娩率、产仔数下降;育成猪生长速度下降、饲料报酬下降、料重比增加;猪群免疫力下降、中暑甚至死亡。各种猪群需要的环境温度不一样,1日龄~3日龄仔猪30℃~33℃,4日龄~7日龄28℃~30℃,8日龄~21日龄26℃~28℃,保育猪20℃~25℃,育肥猪17℃~22℃,母猪、种公猪16℃~20℃。除了初生仔猪,其他猪群适应的温度最高不超过30℃,但是夏季如不采取措施猪舍内温度往往比气温高3℃~5℃,所以夏季热应激给猪群带来的危害可想而知。     

雅士勇制剂对夏季公猪精液保存时间的影响

猪的繁殖性能受到环境、疾病、营养及管理等各方面的影响,其中环境的影响,尤其是夏季高温高湿的影响巨大,并且已经有大量的研究报道,热应激对公猪、母猪的繁殖和育肥猪的生长产生负面的影响。热应激会造成公猪性欲下降,精液品质降低;后备母猪初情期延迟,初情率低;断奶母猪发情率低,断配间隔延长;哺乳母猪采食量下降,哺乳能力下降;育肥猪采食量下降,料重比升高,生长缓慢等问题。所以一到夏季,防暑降温工作是猪场日常工作的重中之重。     

热应激对猪生长发育影响及防治措施

<正>猪属恒温动物,皮下脂肪厚,汗腺不发达,体内热能散发较慢,因此,猪很不耐热。饲养实践证明,猪生长发育需要的适宜温度随体重和年龄增加而下降,初生仔猪为27~29℃,断奶仔猪为21~24℃,生长育肥猪为15~25℃,产仔和哺乳母猪为16~18℃。当猪的产热大于散热,体温升高,容易发生热应激反应。1猪热应激对生猪生长发育的影响1.1对育肥猪生长的影响实践证明,育肥猪生长的适宜温度为15~25℃,当气温在21℃时,育肥猪采食相等的     

补充硒对热应激条件下母猪采食量和产仔性能的影响

<正>母猪皮下脂肪厚,汗腺不发达,体内热能散发较慢,不善于通过皮肤蒸发散热来调节体温,因此高温炎热会对猪群造成很大的应激。妊娠母猪和哺乳母猪最适合繁殖生长的温度值为18~22℃,而我国夏季大部分地区的气温均在30℃以上;再加上集约化的养殖,猪的饲养密度大,母猪往往处在高温环境下。母猪受到高温刺激后,会引发一系列非特异性生理反应,各种机能和代谢功能发生变化,产生热应激反应。例如,热应激条件下的高温对下丘脑嗜食中枢     

癸氧喹酯干混悬剂含量测定的改进

采用高效液相色谱法测定癸氧喹酯干混悬剂的含量,在2-250μg/mL范围内,峰面积的常用对数与进样量浓度的常用对数呈良好的线性关系,R^2=1(n=5),平均回收率为99.24%~99.51%,RSD在0.05%~0.28%。此方法分析时间短,样品前处理简便、定量结果准确,重现性好,结果满意,为其质量控制提供了依据。     

商会自治的基石——商会自治规范研究

在现代法律秩序中,商会自治规范是制定法的基础和必要的补充,甚至在某些方面替代了制定法;商会自治规范主要包括商会组织规范、行为规范、惩罚规范以及争端解决规范等;其效力仅及于其内部成员;商会自治规范和制定法之间存在冲突,但也存在整合的基础。     

猪毛色遗传的研究进展

本文概述了猪的毛色类型、猪的毛色遗传模式,着重综述了猪毛色基因分子基础的研究进展,指出存在问题并就未来发展方向做了思考。     

中华人民共和国农业部公告 第267号

为贯彻落实《兽药生产质量管理规范》(简称《兽药GMP》),进一步推动兽药GMP实施进程,我部制定了《兽药生产质量管理规范检查验收办法》,现予公告。本公告自2003年6月1日起施行。附件:兽药生产质量管理规范检查验收办法二○○三年四月十日第一章 总则 第一条 为推动《兽药生产质量管理规范》(以下简称兽药GMP)的实施,规范兽药GMP检查验收工作,制定本办法。 第二条 农业部负责全国兽药GMP管理和检查验收工作;负责制修订兽药GMP检查验收管理规定;负责兽药GMP检查员队伍建设和监督管理工作,负责国际兽药贸易中GMP互认工作。 …     

鸡败血支原体垂直传播模式及其阻断方法

以国际标准强毒Ｒ株人工感染非免疫产蛋鸡,定时扑杀,分别从鼻窦、眶下孔、气管、肺、气囊、卵巢和输卵管分离ＭＧ,并收集感染鸡所产蛋分离ＭＧ。结果表明,人工感染４８小时后上、下呼吸道及肺已被全面感染,９６小时气囊已被感染,１２０小时输卵管已能分离到ＭＧ,卵巢始终分离不到ＭＧ。人工感染鸡自１４４小时便能在其所产蛋中分离出ＭＧ。药物治疗能在７２小时内消除感染,油乳剂苗则需２４天后逐渐降低蛋内ＭＧ分离率,药物卵内注射、种蛋药浴、高温处理均能杀死卵内ＭＧ,但以研制的种蛋浸泡剂药浴效果为最好。     

Comparison of 2 methods of centesis of the bursa of the biceps brachii tendon of horses

REASONS FOR PERFORMING STUDY: Centesis of the bicipital bursa using an 8.9 cm long spinal needle has been reported but the alternative of employing a 3.8 cm long hypodermic needle requires validation. OBJECTIVE: To compare the efficacy of 2 different methods of centesis of the bicipital bursa and to evaluate the usefulness of ultrasonographic imaging to determine the location of solution administered when centesis of the bursa is attempted. METHODS: For Trial 1, 6 clinicians, who had no previous experience of centesis of the bicipital bursa, attempted to inject a solution composed of an aqueous radiopaque contrast medium and physiological saline solution (PSS) into the bicipital bursae of 2/12 horses using the previously described distal approach to inject one bursa and a proximal approach to inject the contralateral bursa. The bicipital tendon and bursa were examined ultrasonographically before and after injection; and both shoulders were examined radiographically to identify the location of the medium. In Trial 2, another 6 clinicians, also with no previous experience of centesis, repeated Trial 1, using 6 horses, but the radiopaque contrast medium was mixed with air instead of PSS. RESULTS: Accuracy of centesis using the proximal approach was 39% and that of the distal approach 28%. Ultrasonographic examination of the shoulder allowed the location of solution and air to be accurately predicted in all 12 shoulders examined. CONCLUSIONS: Clinicians who have had no previous experience performing centesis of the bicipital bursa are unlikely to be successful in centesis using either approach. Radiographic examination after injecting a radiopaque contrast medium may be necessary to assess the success of centesis especially if bursal fluid is not obtained during centesis. Injecting air along with the radiopaque contrast medium provides more accurate ultrasonographic confirmation of centesis and better radiographic definition than does injection without air.     

不同样本商品蜂蜜中硒含量的测定

用硝酸和高氯酸消化蜂蜜,使硒游离出来,在微酸性环境下,硒和2,3-二氨基萘(DAN)生成有较强荧光的物质,用环己烷萃取,在激发波长378nm,荧光波长518nm处测定其荧光强度。蜂蜜中硒含量范围:0.10～0.82μg/g。表明:蜂蜜应视为天然富硒营养品。     

乳酸杆菌益生作用机制的研究进展

乳酸杆菌作为益生菌广泛用于人和动物。本文综述了乳酸杆菌改善宿主健康的机制。乳酸杆菌可通过产生抗菌物质如乳酸、过氧化氢、细菌素,或者通过竞争营养或肠道黏附位点来抑制致病菌;通过诱导黏附素的分泌或阻止细胞凋亡而增强肠道的屏障功能,从而保护肠道。文章重点讨论了乳酸杆菌表面成分（表面蛋白、脂磷壁酸和肽聚糖）与肠道受体（Ｃ型凝集素受体、Ｔｏｌｌ样受体和 Ｎｏｄ样受体）,阐述了他们结合后启动免疫调节信号,调控肠道免疫功能以发挥改善健康作用的机制。     

Effects of size of ingestively masticated fragments of plant tissues on kinetics of digestion of NDF

Ingestively masticated fragments were collected and sized via sieving. Different sizes of esophageal masticate and ruminal digesta fragments, and ground fragments of larger masticated pieces were incubated in vitro, and undigested NDF remaining at intervals of up to 168 h of incubation was determined. The ruminal age-dependent time delay (tau) for onset of digestion of NDF was positively correlated (P < 0.004) with the mean sieve aperture estimated to retain 50% of the fragments between successive sieve apertures (MRA). Degradation rate of potentially degradable NDF (PDF) and level of indigestible NDF were not related (P > 0.10) to MRA of masticated and ground fragments. Estimates of tau were positively related to MRA, with slopes of bermudagrass < corn silage < ruminal fragments of corn silage. It was concluded that fragment size-, and consequently, ruminal age-dependent onset of PDF degradation of a mixture of different fragment sizes results in an age-dependent rate of degradation of the more rapidly degrading of two subentities of PDF. Models are proposed that assume a tau before onset of simultaneous degradation of PDF from two pools characterized as having gamma-modeled age-dependency and age-constant rates. The ruminal age-dependent pool seems to be associated with the faster-degrading pool, and its rate parameter increases with range in MRA in the population of fragments. Conceptually, the ruminal age-dependent rate parameter for PDF degradation seems to represent a composite of several effects: 1) effects of the size-dependent tau; 2) range in MRA of the population of ingestively masticated fragments; and 3) subentities of PDF that degrade via more rapid age-dependent rates compared with subentities of PDF that degrade via age-constant rates. The estimated fractional rates of ruminative comminution of ingestively masticated fragments (0.060 to 0.075/h) were of a magnitude similar to the mean fractional rates of PDF digestion (0.030 to 0.085/h), which implies that ruminative comminution may be first-limiting to fractional rate of PDF digestion. The in vivo roles of ingestive and ruminative mastication of fragments on PDF degradation must be considered in any kinetic system for estimating PDF digestion in the rumen. These results and others in the literature suggest that the rate of surface area exposure rather than intrinsic chemical attributes of PDF may be first-limiting to degradation rate of PDF in vivo.