夏季普遍高溫,尤其在我國南方地區,氣溫常在30 ℃~35 ℃之間,濕度常高於70%,且持續時間較長,長達4個月。豬是恒溫動物,皮下脂肪較厚,汗腺不發達,因此,這種夏季高溫高濕環境對豬的采食量、日增重、飼料利用率、母豬懷胎率和產仔率、公豬的精子質量、仔豬存活率等生產繁殖性能產生很大的影響。生產實踐證明,當環境溫度達到30 ℃以上時,如不采取降溫措施,各類豬群(除哺乳仔豬外)將會處於熱應激狀態,豬的健康狀況和生產性能將受到很大影響:母豬不發情,受胎率和產仔數明顯降低;分娩母豬表現出煩躁、采食量下降,泌乳量減少,失重較多;造成仔豬初生體重較輕,增重減慢、存活率低;種公豬交配和產精能力下降;feiyuzhukangrejiyidiaobiao,shengchangzhiman,siliaoliyonglvhezhurizengzhongxiajiang,shenzhizhongshusiwangdeng。yinci,zaixiajigaowenjijie,bixujiaqiangfangshujiangwengongzuo,duizhusheneihuanjingwendujinxingkongzhi,quebaoshengzhuanquanyuexia,tigaoyangzhuxiaoyi。
1 各類豬群的溫度要求
各類豬群對環境溫度的要求各不相同,初生仔豬的適宜生長溫度為34 ℃~35 ℃;3~4周齡仔豬的適宜生長溫度為30 ℃左右; 稍大仔豬的適宜生長溫度為20 ℃~23 ℃;成豬生長的適宜溫度為17 ℃~22 ℃。我們可以看出,除仔豬外,其他各類豬群的適宜溫度均在30℃以下,大大低於我國大部分地區,尤其是南方地區的夏季氣溫(30 ℃~35 ℃之間),yinci,weilebaozhangxiajizhuchangdezhengchangshengchan,bixuduizhushejinxingjiangwen,erqieyouyugeleizhuqunsuoyaoqiudewendubutong,jiangwenfangfayebixugenjushijiqingkuangqueding。
2 豬舍的降溫措施
近(jin)年(nian)來(lai),國(guo)內(nei)外(wai)研(yan)究(jiu)開(kai)發(fa)了(le)多(duo)種(zhong)適(shi)合(he)於(yu)不(bu)同(tong)豬(zhu)群(qun)的(de)降(jiang)溫(wen)設(she)施(shi),已(yi)在(zai)集(ji)約(yue)化(hua)養(yang)豬(zhu)生(sheng)產(chan)中(zhong)得(de)到(dao)了(le)廣(guang)泛(fan)應(ying)用(yong),大(da)大(da)減(jian)輕(qing)了(le)封(feng)閉(bi)飼(si)養(yang)環(huan)境(jing)下(xia)夏(xia)季(ji)熱(re)應(ying)激(ji),為(wei)規(gui)模(mo)化(hua)豬(zhu)場(chang)實(shi)現(xian)全(quan)年(nian)均(jun)衡(heng)生(sheng)產(chan)提(ti)供(gong)了(le)保(bao)障(zhang)。豬(zhu)舍(she)的(de)降(jiang)溫(wen)手(shou)段(duan)包(bao)括(kuo)外(wai)圍(wei)護(hu)結(jie)構(gou)隔(ge)熱(re)、豬舍的建築隔熱設計和畜舍降溫設備。
2.1 豬舍的建築隔熱設計
目前在生產實踐中對豬舍建築的隔熱、fangshushejizhuyaogenjudangdiqihoutedianhelijianzhuzhushedechaoxianghejianju,jiangzhushewaiqiangyongshihuishuituchengbaise,yitigaozhushewaibiaomiandefanshenengliheresanshilv,congerjianshaotaiyangrenengduizhusheneihezhutidechuandi,caiyongdaorexishujiaoxiaodewudingcailiaohuocaiquduowujianzhugouzaodengwudinggeresheji,qiangbidegereshejiyongkongxinzhuandaitiputongzhantuzhuanzuoqiangticailiao,keshiqirezutigao41%,而用加氣混泥土塊可提高6倍,采用雙層牆體也會大大提高牆體的熱阻值。在豬舍外圍種植樹木、攀緣植物或用蘆葦、窗簾、屋緣等遮擋陽光直接射入豬舍。
2.2 通風
夏(xia)季(ji),對(dui)豬(zhu)舍(she)進(jin)行(xing)有(you)效(xiao)的(de)通(tong)風(feng)可(ke)以(yi)排(pai)出(chu)豬(zhu)舍(she)內(nei)的(de)熱(re)量(liang),對(dui)降(jiang)低(di)舍(she)內(nei)溫(wen)度(du)有(you)一(yi)定(ding)的(de)作(zuo)用(yong)。目(mu)前(qian)豬(zhu)舍(she)的(de)通(tong)風(feng)方(fang)式(shi)有(you)自(zi)然(ran)通(tong)風(feng)和(he)機(ji)械(xie)通(tong)風(feng)兩(liang)種(zhong)。自(zi)然(ran)通(tong)風(feng)是(shi)在(zai)豬(zhu)舍(she)建(jian)築(zhu)中(zhong)設(she)置(zhi)合(he)適(shi)的(de)進(jin)出(chu)風(feng)口(kou),利(li)用(yong)自(zi)然(ran)風(feng)力(li)及(ji)溫(wen)差(cha)作(zuo)用(yong)將(jiang)新(xin)鮮(xian)空(kong)氣(qi)引(yin)入(ru)舍(she)內(nei),將(jiang)舍(she)內(nei)多(duo)餘(yu)的(de)熱(re)量(liang)和(he)汙(wu)濁(zhuo)氣(qi)體(ti)排(pai)出(chu)室(shi)外(wai)。機(ji)械(xie)通(tong)風(feng)目(mu)前(qian)常(chang)采(cai)用(yong)縱(zong)向(xiang)通(tong)風(feng),將(jiang)風(feng)機(ji)安(an)裝(zhuang)在(zai)豬(zhu)舍(she)的(de)山(shan)牆(qiang)上(shang)以(yi)便(bian)縱(zong)向(xiang)通(tong)風(feng),將(jiang)舍(she)內(nei)高(gao)溫(wen)空(kong)氣(qi)用(yong)風(feng)機(ji)排(pai)出(chu)而(er)將(jiang)舍(she)外(wai)涼(liang)爽(shuang)的(de)新(xin)鮮(xian)空(kong)氣(qi)引(yin)入(ru)室(shi)內(nei)。對(dui)豬(zhu)舍(she)通(tong)風(feng)起(qi)到(dao)較(jiao)好(hao)的(de)作(zuo)用(yong)。
當外界氣溫顯著低於豬隻體溫時,通風可以有效散發豬體的體熱,但空氣溫度高於25 ℃,通風的降溫效果就明顯變差,當氣溫達到30 ℃以上時,單靠通風仍不能有效降低舍內氣溫。所以高溫時就應考慮先將空氣冷卻後再送入豬舍。如利用地下管道、地道等進行通風降溫,舍外空氣可以先進入地下管道、地道或自然洞穴,再進入豬舍,可將舍外空氣降低3 ℃~5 ℃,舍內溫濕度低於85%。為保障地道通風降溫方式的效果,往往需要開挖較深的地道,多深達3~4 m,並有足夠長度,因此工程量較大,一次投入也較大,接近於人工製冷係統,但運行費用很低,如有現成的的地道如廢礦井、天然洞穴等可以利用,則會大大降低一次性投入,且這種係統還可兼有冬季取暖的作用,減少豬舍內的四季溫度變化。
2.3 蒸發降溫
國外密閉豬舍降溫主要依靠濕簾-風機降溫係統,或機械通風輔助局部的降溫,如設置噴霧、噴淋、滴(di)水(shui)係(xi)統(tong),或(huo)結(jie)合(he)地(di)下(xia)管(guan)道(dao)通(tong)風(feng)來(lai)進(jin)行(xing)降(jiang)溫(wen)。我(wo)國(guo)也(ye)在(zai)這(zhe)些(xie)方(fang)麵(mian)進(jin)行(xing)研(yan)究(jiu)並(bing)加(jia)以(yi)應(ying)用(yong),目(mu)前(qian)我(wo)國(guo)可(ke)在(zai)畜(chu)禽(qin)舍(she)內(nei)應(ying)用(yong)的(de)蒸(zheng)發(fa)降(jiang)溫(wen)係(xi)統(tong)有(you)濕(shi)簾(lian)風(feng)機(ji)降(jiang)溫(wen)係(xi)統(tong)、噴淋降溫係統、噴霧降溫係統等。均是利用水蒸發吸熱實現冷卻的蒸發降溫技術,蒸發降溫具有效果顯著、節能、一次性投入少,運行可靠及維護方便等優點。不僅適用於我國氣候幹燥的北方地區,也適用於我國南方大多數地區。
1) 濕簾風機降溫係統
濕簾風機降溫在農業建築中應用較多,效果也非常顯著,用於畜禽舍的夏季降溫,取得良好的效果,中國農業大學東校區於1988年成功研製了適合我國條件的濕簾風機係統,並與9FJxiliefengjiyiqibeilieruguojiaxinchanpinxiangquanguotuiguangyingyong,zhexiangjishuyuzongxiangtongfengjishuxiangjiehe,yijingchengweimuqiannongyejianzhuxiajitongfengjiangwendezuijiamoshi。shilianfengjijiangwenxitongzhuyaoyoushilianfengji、shuixunhuanxitonghekongzhizhuangzhizucheng,qihexinbufenshishilian。qijutishejishijiangshilianzhuangzaizhushedeyiduanshanqiang,fengjizhuangzailingyiduanshanqiangbi,fengjichoufengshi,sheneichanshengfuya,shishewaikongqitongguoshirundeshilianbiaomianjinrusheneierjiangwen。jingshijishiyongceshibiaoming,shilianhouduwei12 cm,過簾風速為1.0~1.2 m/s時,濕簾降溫效率為81%~87%。
濕簾-風機降溫係統具有設備簡單,成本低廉能耗低,產冷量大,運行可靠方便、自動控製等優點,適合於豬場配種舍、種公豬舍、妊娠舍和育肥豬舍使用,當舍外的溫度達到35 ℃~37 ℃時,濕簾風機係統可將舍內溫度降低到30 ℃以下,而僅用風機降溫的豬舍溫度則高達33 ℃左(zuo)右(you)。另(ling)外(wai)使(shi)用(yong)濕(shi)簾(lian)風(feng)機(ji)降(jiang)溫(wen)係(xi)統(tong)的(de)豬(zhu)舍(she)內(nei)蚊(wen)蠅(ying)也(ye)明(ming)顯(xian)減(jian)少(shao),衛(wei)生(sheng)環(huan)境(jing)改(gai)善(shan),大(da)大(da)提(ti)高(gao)了(le)夏(xia)季(ji)高(gao)溫(wen)季(ji)節(jie)豬(zhu)的(de)福(fu)利(li)狀(zhuang)況(kuang)。使(shi)用(yong)過(guo)程(cheng)中(zhong)應(ying)注(zhu)意(yi)對(dui)濕(shi)簾(lian)的(de)維(wei)護(hu),防(fang)止(zhi)結(jie)垢(gou)和(he)鼠(shu)類(lei)的(de)破(po)壞(huai)。
2) 噴淋降溫係統
penlinjiangwenxitonggenjupenlinqianzhuangweizhibutongkefenweisheneipenlinjiangwenxitonghewumianpenlinjiangwenxitong。sheneipenlinjiangwenshizhizaisheneizhuhuodongquyushangfanganzhuangpentou,meigeyidingshijianxiangzhutizhijiepenshui,shuizaizhushentibiaomianzhengfajiangreliangdaizou。zheleijiangwenxitongzhuangzhijiandan,shebeitouziheyunxingfeiyongdouhendi,danrongyizaochengdimianjishui,zengjiasheneishidu,suoyizaishiyongzheleijiangwenfangfashiyingtebiezhuyi,yibancaiqujianxieyunxing,genjushijideqiwen、濕度和通風條件確定間隔時間和噴淋時間,通常間隔45~60 min,噴淋1~2 min。屋wu麵mian噴pen淋lin是shi指zhi在zai屋wu頂ding上shang安an裝zhuang噴pen淋lin係xi統tong,利li用yong噴pen淋lin器qi噴pen出chu水shui形xing成cheng的de水shui膜mo和he水shui的de汽qi化hua蒸zheng發fa達da到dao降jiang溫wen的de目mu的de。其qi缺que點dian是shi容rong易yi形xing成cheng水shui垢gou沉chen積ji,且qie用yong水shui量liang大da。
3) 噴霧降溫係統
多采用高壓噴頭將水滴霧化成直徑在50~80 μm以(yi)下(xia)的(de)霧(wu)滴(di),使(shi)水(shui)滴(di)在(zai)落(luo)到(dao)動(dong)物(wu)或(huo)地(di)表(biao)麵(mian)以(yi)前(qian)就(jiu)完(wan)全(quan)汽(qi)化(hua),從(cong)而(er)吸(xi)收(shou)室(shi)內(nei)熱(re)量(liang),達(da)到(dao)降(jiang)溫(wen)目(mu)的(de)。國(guo)外(wai)研(yan)究(jiu)表(biao)明(ming),高(gao)壓(ya)噴(pen)霧(wu)係(xi)統(tong)在(zai)育(yu)肥(fei)豬(zhu)舍(she)和(he)斷(duan)奶(nai)母(mu)豬(zhu)舍(she)夏(xia)季(ji)降(jiang)溫(wen)使(shi)用(yong)情(qing)況(kuang)效(xiao)果(guo)較(jiao)好(hao),降(jiang)溫(wen)幅(fu)度(du)達(da)5 ℃同tong時shi也ye可ke以yi減jian少shao豬zhu舍she內nei的de粉fen塵chen。另ling外wai一yi種zhong噴pen霧wu降jiang溫wen係xi統tong是shi集ji中zhong細xi霧wu降jiang溫wen係xi統tong此ci法fa也ye稱cheng為wei沸fei騰teng爐lu式shi集ji中zhong霧wu化hua降jiang溫wen係xi統tong,是shi在zai建jian築zhu的de進jin風feng口kou處chu設she置zhi噴pen霧wu室shi進jin行xing集ji中zhong噴pen霧wu降jiang溫wen,使shi霧wu滴di產chan生sheng類lei似si於yu工gong業ye沸fei騰teng爐lu中zhong粉fen粒li的de運yun動dong,增zeng加jia了le氣qi流liu與yu水shui滴di的de接jie觸chu時shi間jian,提ti高gao了le降jiang溫wen效xiao果guo,並bing且qie未wei蒸zheng發fa完wan的de霧wu滴di可ke落luo入ru集ji水shui池chi循xun環huan使shi用yong,避bi免mian了le在zai室shi內nei直zhi接jie噴pen霧wu淋lin濕shi豬zhu表biao和he地di麵mian的de問wen題ti,對dui泵beng和he噴pen霧wu裝zhuang置zhi的de要yao求qiu同tong時shi也ye大da大da降jiang低di,該gai係xi統tong相xiang當dang於yu在zai吸xi氣qi口kou的de外wai側ce設she置zhi噴pen霧wu室shi代dai替ti濕shi簾lian,我wo國guo學xue者zhe研yan究jiu表biao明ming,在zai夏xia季ji室shi外wai相xiang對dui濕shi度du55%~60%。幹濕球溫差6 ℃~8 ℃左右的常見情況下,集中細霧降溫裝置可將進入舍內的空氣氣溫降低5 ℃~6 ℃,舍內平均氣溫比舍外低4 ℃左右,舍內相對濕度一般不高於80%。美國學者報道,細霧降溫係統投資較低,(在美國相當於濕墊降溫係統的一半左右),且適應性廣,密閉與開放舍、機(ji)械(xie)通(tong)風(feng)與(yu)自(zi)然(ran)通(tong)風(feng)均(jun)可(ke)采(cai)用(yong),使(shi)用(yong)靈(ling)活(huo),噴(pen)霧(wu)設(she)施(shi)可(ke)兼(jian)用(yong)作(zuo)消(xiao)毒(du)。但(dan)是(shi)細(xi)霧(wu)降(jiang)溫(wen)的(de)降(jiang)溫(wen)效(xiao)率(lv)還(hai)是(shi)比(bi)濕(shi)墊(dian)低(di),主(zhu)要(yao)原(yuan)因(yin)在(zai)於(yu)細(xi)霧(wu)分(fen)布(bu)不(bu)均(jun)勻(yun),部(bu)分(fen)空(kong)間(jian)因(yin)分(fen)布(bu)霧(wu)滴(di)少(shao)降(jiang)溫(wen)效(xiao)果(guo)不(bu)好(hao)。
在zai夏xia季ji降jiang溫wen的de各ge種zhong手shou段duan中zhong,蒸zheng發fa降jiang溫wen是shi最zui經jing濟ji的de,不bu足zu之zhi處chu在zai降jiang溫wen的de同tong時shi也ye會hui使shi濕shi度du增zeng加jia,這zhe是shi由you其qi降jiang溫wen原yuan理li決jue定ding的de,難nan以yi克ke服fu的de缺que陷xian,因yin此ci在zai濕shi度du較jiao大da的de天tian氣qi不bu能neng達da到dao好hao的de降jiang溫wen效xiao果guo,因yin此ci要yao在zai這zhe些xie限xian製zhi以yi內nei盡jin量liang發fa揮hui蒸zheng發fa降jiang溫wen的de潛qian力li,是shi蒸zheng發fa降jiang溫wen技ji術shu之zhi難nan點dian所suo在zai。盡jin管guan有you其qi局ju限xian性xing,但dan由you於yu能neng解jie決jue農nong業ye建jian築zhu夏xia季ji生sheng產chan中zhong高gao溫wen這zhe個ge主zhu要yao矛mao盾dun,而er且qie經jing濟ji性xing好hao,因yin此ci仍reng然ran不bu失shi為wei農nong業ye建jian築zhu夏xia季ji生sheng產chan的de有you效xiao降jiang溫wen手shou段duan。
2.4 豬舍地板局部降溫係統
這類降溫係統是指以地下水為媒介、在豬的躺臥區地板下部鋪設排管的一種傳導降溫方式,適用於有地下水源、可以打井的地區。該係統由於是局部降溫,因而不僅適合於育肥豬、妊(ren)娠(shen)母(mu)豬(zhu)等(deng)大(da)豬(zhu),而(er)且(qie)適(shi)合(he)於(yu)哺(bu)乳(ru)舍(she)母(mu)豬(zhu)活(huo)動(dong)和(he)躺(tang)臥(wo)區(qu)域(yu)的(de)降(jiang)溫(wen),不(bu)僅(jin)封(feng)閉(bi)式(shi)豬(zhu)舍(she),對(dui)開(kai)放(fang)舍(she)也(ye)可(ke)作(zuo)為(wei)環(huan)境(jing)調(tiao)控(kong)的(de)一(yi)個(ge)措(cuo)施(shi)加(jia)以(yi)應(ying)用(yong),有(you)利(li)於(yu)改(gai)善(shan)豬(zhu)隻(zhi)飼(si)養(yang)環(huan)境(jing),減(jian)少(shao)高(gao)溫(wen)對(dui)豬(zhu)隻(zhi)生(sheng)產(chan)力(li)的(de)影(ying)響(xiang),具(ju)有(you)簡(jian)化(hua)建(jian)築(zhu)結(jie)構(gou),降(jiang)低(di)建(jian)築(zhu)成(cheng)本(ben)和(he)生(sheng)產(chan)成(cheng)本(ben)等(deng)優(you)點(dian)。實(shi)測(ce)表(biao)明(ming),當(dang)舍(she)外(wai)溫(wen)度(du)高(gao)達(da)34 ℃時,地下水地板降溫區域溫度基本不超過26 ℃,一般穩定在22 ℃~26 ℃。
3 結論
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