溫熱環境對母豬生產性能的影響及其調控技術研究進展

曾雅瓊，王浩,2，劉作華，李爽，蒲施樺,2，龍定彪,2

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溫熱環境對母豬生產性能的影響及其調控技術研究進展

曾雅瓊1，王浩1,2，劉作華1，李爽1，蒲施樺1,2，龍定彪1,2

（1重慶市畜牧科學院，重慶 402460；2農業部西南設施養殖工程科學觀測實驗站，重慶 402460）

生豬養殖業是我國農業和農村經濟的支柱性產業之一，母豬作為生豬養殖場的核心豬群，其生產性能是決定生豬養殖場經濟效益的關鍵因素。我國是世界生豬養殖的第一大國，能繁母豬存欄量和商品豬出欄量均超過世界總量的50%，然而，與發達國家相比，我國母豬飼養管理水平較低，在生產性能方面仍存在較大差距。實際生產中母豬的生產性能受到諸多因素的影響，主要包括母豬的營養攝取、機體特性、飼養空間環境及胎次等，其中溫熱環境是影響母豬健康和生產性能的重要因素之一。溫熱環境包括溫度、相對濕度、空氣流動、輻射及熱傳遞等因素，他們共同作用于動物，使動物產生冷或熱、舒適與否的感覺。適宜的溫熱環境有利于保障母豬的機體健康，提高其生產性能，反之，不適宜的溫熱環境會引起母豬的熱環境應激，破壞體熱平衡，甚至導致生產停止，使機體進入病理狀態，引發疾病甚至死亡。因此，掌握母豬的溫熱環境需求并采取有效的調控措施，對提高母豬生產性能和生豬養殖場經濟效益至關重要。文章從溫熱環境對母豬的影響和溫熱環境調控技術兩個方面進行綜述，旨在為我國生豬養殖場母豬生產管理的溫熱環境調控提供理論依據和技術支撐。（1）溫熱環境對母豬的影響方面。溫熱環境對母豬的影響主要體現在行為、生理和生產性能等方面的變化。在行為方面，高溫環境下，由于側臥時母豬體表與地面的接觸面積更大，可增加機體散熱量，母豬會通過行為姿勢改變進行熱調節，如增加側臥時間、減少站立和俯臥時間，而母豬姿勢行為的頻繁改變會增加仔豬壓死率。在生理方面，熱應激時母豬會通過減少采食量、增加呼吸率和皮膚血流量等途徑來減少代謝產熱、增加散熱，同時母豬血液中促腎上腺皮質激素和皮質醇會增加、甲狀腺素降低、胰島素敏感性增加，這些生理變化會破壞母豬機體內分泌和能量平衡，進而導致胚胎早期死亡、流產和泌乳量下降。在生產性能方面，熱應激會對母豬發情間隔、產仔數和泌乳量等生產性能造成不利影響，妊娠前期熱應激主要影響返情率和產仔數，妊娠后期主要影響產活仔數和死胎數，分娩后則主要影響仔豬存活率，環境高溫通過影響母豬的泌乳量對哺乳仔豬生產性能產生不利影響，通過影響母豬的采食量、泌乳期母豬失重和體內生殖激素的分泌，導致母豬斷奶后發情延遲。（2）溫熱環境調控技術方面。母豬溫熱環境調控技術主要包括豬舍整體降溫和局部降溫兩種，整體降溫以“濕簾-風機”蒸發冷卻降溫技術為代表，通過風機排風造成舍內負壓，迫使舍外未飽和的空氣流經濕潤的多孔濕簾，引起水分蒸發吸收大量潛熱，降低進入舍內的空氣溫度，從而達到降低舍內溫度的目的，該技術具有設備簡單、經濟高效的優勢。豬舍局部降溫主要是針對豬只躺臥區地板、兩側豬欄、豬欄上方等區域進行溫度調控，主要有風管噴氣嘴蒸發冷卻、冷水覆蓋降溫和豬舍地板降溫等方式，具有降溫效果良好和節能的優點。

母豬；溫熱環境；調控；生產性能

我國是世界生豬養殖的第一大國，生產母豬存欄量和商品豬出欄量均超過世界總量的50%[1]，是我國農業和農村經濟的支柱性產業之一。母豬作為生豬養殖場的核心豬群，其繁殖性能是決定生豬養殖場經濟效益的關鍵環節。我國的母豬管理水平與發達國家相比還存在較大差距，我國平均每頭生產母豬年提供商品肥豬（MSY）不超過15頭，年產胎次（LYS）為2.2，而歐洲、加拿大、美國等國家MYS則超過25頭，丹麥更是超過30頭，LYS則達到2.3—2.4[2]。母豬的生產繁殖性能由營養、機體特性、飼養環境及胎次[3-6]等多種因素共同決定，其中溫熱環境是重要影響因素之一，適宜的溫熱環境有利于保障母豬的健康狀況，提高其生產和繁殖性能，反之則會引起母豬的熱應激，破壞體熱平衡，甚至導致生產停止，使機體進入病理狀態，引發疾病甚至死亡[7-8]。因此，掌握母豬的溫熱環境需求并采取有效的調控措施，對提高母豬生產繁殖性能和生豬養殖經濟效益至關重要。

本文以母豬為對象，以溫熱環境為影響因素，通過對國內外相關研究成果的綜述、分類和總結，闡述了溫熱環境對母豬繁殖性能、行為習性和生理狀況等的影響，并詳細介紹國內外母豬溫熱環境調控新技術、新方法和新設備，旨在為我國生豬養殖場母豬生產管理的溫熱環境調控提供理論依據和技術支撐。

1 溫熱環境對母豬的影響

1.1 生產性能

熱應激對養豬業的經濟效益影響巨大，其主要表現為母豬生產性能的下降所造成的經濟損失。據統計在美國由熱應激所導致的母豬經濟損失高達4.5億美元/年[9-10]，而熱應激對母豬生產性能產生的不利影響主要體現在產仔數、仔豬成活率、泌乳量、斷奶至發情間隔等方面[11-12]，且存在生理階段差異。

熱應激對母豬產仔數的不利影響存在生理階段差異性：妊娠前期熱應激主要影響返情率及產仔數，妊娠后期熱應激主要影響產活仔數和死胎數，分娩后熱應激則主要影響仔豬存活率。TUMMARUK等[13]認為在妊娠早期（1—35 d）高溫應激顯著降低產仔數和產活仔數，而妊娠晚期的高溫應激（102—110 d）導致死胎率升高[14]。 TANTASUPARUK等[15]認為在妊娠前四周豬舍每日最高溫度提高1℃，窩產仔數降低0.07頭。BLOEMHOF等估算得出影響產仔數和分娩率的溫度上限閾值分別為21.7℃和19.2℃[16]，而我國南方地區夏季豬舍平均溫度在29℃以上[17-18]。李延森等[19]報道江蘇鹽城環境溫度對母豬繁殖性能的影響，夏季（7月份）最高氣溫時，母豬的總產仔數（10.9頭）和斷奶活仔數最低（7.65頭），胎均死胎數最高（0.49），并且溫度與返情率呈正相關，與7d發情率呈負相關。WEGNER等[8]研究了溫度（15—25℃）對夏季母豬繁殖性能的影響，發現配種前6d至配種后14d期間高溫顯著降低母豬窩產仔數（＜0.05）；產前4d內的高溫環境顯著降低活仔數（＜0.05）、提高死胎數（＜0.001），環境溫度每升高1℃，窩產仔數減少0.03頭；分娩至產后12d，高溫環境顯著降低仔豬存活率（＜0.05），溫度每升高1℃，窩活仔數減少0.02頭。

環境高溫通過影響母豬的泌乳量對哺乳仔豬生產性能產生不利影響。高溫環境下，母豬通過減少采食量和增加體表皮膚的血液流量，達到降低產熱、增加散熱的目的，從而導致母豬乳腺合成乳汁需要的養分減少，降低母豬的泌乳量[20-22]。

SPENCER等[23]研究發現，與21℃相比，高溫環境下（32℃）母豬產后第第14天采食量顯著降低（7.97kg vs 4.83kg，＜0.01）、母豬失重顯著增加（-1.8kg vs 16.6kg，＜0.01）、泌乳量降低約30%（＜0.01）WILLIAMS等[24]研究發現，與適宜溫度環境相比（18—20℃），高溫環境（24—30℃）下的哺乳仔豬斷奶重顯著降低了0.5kg（＜0.05）；PRUNIER等[25]報道，與適宜環境溫度（18℃）相比，高溫環境（27℃）顯著提高了6—21日齡哺乳仔豬的死亡數（0.2頭 vs 0.7頭，＜0.05），極顯著降低母豬哺乳期采食量（6.10kg vs 4.40kg，＜0.001）和仔豬斷奶重（6.44kg vs 5.09kg，＜0.001）；SURIYASOMBOON等[26]的研究也證實了斷奶前期、配種期和分娩時環境高溫高濕會對仔豬產生不利影響。林映才等[27]總結了大量國外高溫環境對母豬及仔豬的影響，發現與適溫條件相比（18—22℃），熱應激（28—32℃）可使泌乳母豬采食量降低40%，泌乳量減少25%，仔豬增重減少20%，體重損失增加2.6倍。

斷奶至發情間隔直接影響母豬生產周期及年生產力[28]，熱應激通過影響母豬的采食量、泌乳期母豬失重和體內生殖激素的分泌，進而導致母豬斷奶后發情延遲。研究指出，有9%的分娩母豬在夏季高溫時出現發情延遲現象[29]，且配種率下降，當豬舍環境溫度高于23℃時，母豬配種率極顯著降低（=0.001）[30]。PRUNIER等[25]研究發現，與適宜環境溫度（18℃）相比，高溫（27℃）導致母豬斷奶后10 d內的發情率顯著降低（13/17 vs 7/18，＜0.05）。BOMA等[31]研究表明，隨著環境溫度的升高，母豬斷奶至發情間隔的時間逐漸增加，當平均溫度在37.2℃時發情間隔顯著高于25.6℃時的發情間隔（12.7 d vs 7.9 d）。高溫環境下，母豬斷奶至發情間隔增加，發情延遲則母豬空懷期延長，且生產者無法預測或保持仔豬輸出量，影響豬場生產力和經濟效益[32-33]，因此，有必要在夏季高溫時采取措施緩解母豬熱應激。

1.2 行為及福利

行為是評價動物適應環境變化的重要指標。熱應激時母豬熱舒適性較差，會出現哺乳、躺臥姿勢、采食等行為變化，降低其福利水平，增加仔豬的壓死率[34-35]。高溫環境下，母豬會通過行為姿勢改變進行熱調節，如減少站立時間、增加側臥時間、減少俯臥時間等，側臥時母豬體表與地面的接觸面積更大，增加了機體傳導散熱量。MUNS等[36]從分娩前16h至分娩后24h連續測定了母豬的行為，發現兩組母豬（20℃和25℃）躺臥、坐和站立行為無顯著差異（＞0.05），但躺臥的姿勢存在顯著差異，與對照組（20℃）相比，熱應激環境（25℃）顯著提高母豬分娩前16h（47.3% vs 61.5%，=0.003）和分娩后24h（81.6% vs 92.6%，=0.018）側臥姿勢的時間，顯著降低母豬分娩前16h（61.3% vs 25.2%，=0.001）和分娩后24h（11.1% vs 3.9%，=0.038）俯臥姿勢的時間。高婭俊等[35]研究了高溫（30.4℃）和低溫（15.3℃）對分娩母豬行為的影響，發現低溫組均顯著提高母豬站立（10% vs 21.7%）、跪立（0.2% vs 0.4%）、腹臥（14% vs 25%）和臀部下落時間（3.4s vs 4.0s），降低側臥時間（66.9% vs 42.1%）以及母豬6 h內的坐立-腹臥（4.7 vs 2.2）、腹臥-坐立（4.9 vs 2.5）的轉換頻次。由于母豬的坐立-腹臥、站立-躺臥行為的轉換以及臀部快速下落常常導致仔豬的壓死，高溫導致仔豬的壓死率顯著升高（15.2% vs 0），CANADAY等[37]的研究結果與其一致。DEVILLERS和FARMER[34]研究了環境溫度對分娩母豬行為的影響，發現與適溫環境（21℃）相比，高溫（29℃）顯著減少哺乳母豬的站立時間（11.4% vs 9.3%，=0.008），縮短哺乳時長（6.2 min vs 5.4min，=0.01），提高哺乳頻率（34.4 vs 37.5，＜0.001），這可能是由于高溫環境下母豬產奶量下降，仔豬由于饑餓而刺激母豬的哺乳行為。QUINIOU等[38]研究發現高溫環境下（29℃）泌乳母豬的采食次數（4.8 vs 7.3）、采食量（3 495g vs 6 423g）、采食時間（29.6min·d-1vs 50.4min·d-1）均比25℃環境顯著降低，而飲水量顯著提高（7.1l/kg采食量 vs 4.4l/kg采食量），并且高溫環境顯著降低夜間采食比例（10% vs 23%）。

1.3 生理狀況

母豬自身的體熱調控能力差，當其處于熱應激狀態時，會通過減少采食量、增加呼吸率和皮膚血流量等途徑來減少代謝產熱、增加散熱以適應高溫環境，但當其直腸溫度升高時，上述熱調控方式就不能完全補償熱應激帶來的不利影響，導致長時間的能量負平衡和母豬機體受損[39]。熱應激環境對初產母豬的生理狀況影響更為明顯，泌乳期的熱應激導致初產母豬的直腸溫度顯著高于經產母豬（39.0℃ vs 38.7℃，＜0.019），這表明高溫降低初產母豬能量穩衡的能力，并可能降低代謝能轉化為母乳的能力[40-41]。熱環境下，母豬體熱調節平衡被破壞，交感神經興奮，顯著增加豬只呼吸量，使得呼吸頻率增加和深度變淺，呼吸頻率可超過40次/min[41-42]，DE OLIVEIRA等[43]報道，與21.0℃相比，25.7℃環境中分娩母豬的呼吸頻率顯著提高（早上：28.0次/min vs 43.7次/min；下午：33.7次/min vs 61.7次/min），但直腸溫度無顯著差異。WILLIAMS等[24]報道，分娩欄中處于熱應激環境（24—30℃）中的母豬，其直腸溫度顯著高于（＜0.001）適溫環境（18—20℃）中的母豬；熱應激環境中母豬的呼吸頻率約是適溫環境中母豬的2倍。MUNS等[36]的研究發現，與適溫環境（20℃）相比，高溫環境（25℃）顯著提高了母豬產前1 d (=0.033)和分娩當天（=0.004）的呼吸頻率；提高了分娩前1d到分娩后8d的直腸溫度，并且分娩后1d達到顯著水平；分娩3d內的平均乳腺表面溫度提高了0.9℃。

腎上腺和甲狀腺在維持機體代謝、調節機體穩態中起著重要作用，高溫環境可以改變母豬體內激素水平[44]。熱應激時，母豬機體通過增加下丘腦促腎上腺皮質激素釋放激素，促進促腎上腺皮質激素分泌來對抗熱應激，而促腎上腺皮質激素的分泌會抑制促卵泡素和促黃體素的分泌，導致母豬黃體、孕酮不足，出現胚胎早期死亡及流產[45]。MALMKVOST等[46]在母豬產前12h至產后48h給予地板加熱處理（33—34℃）發現，與對照組相比，地板加熱處理組母豬的皮質醇和促腎上腺皮質激素分別提高了29%(=0.02)和17%(=0.08)。BARB等[47]研究發現，與22℃飼養環境相比，30℃下母豬的甲狀腺素水平下降30%，黃體化激素水平不變，但其脈沖頻率（＜0.003）和振幅（＜0.03）均顯著提高。PRUNIER等[25]的研究結果顯示，與20℃相比，30℃熱應激環境顯著降低母豬血清三碘甲狀腺氨酸濃度（＜0.05），提高血糖濃度（＜0.001）。熱應激時豬只胰島素的敏感性增加，免疫系統是潛在的葡萄糖利用者，且免疫系統一旦激活，免疫細胞就會變成葡萄糖利用者，并改變了機體的能量穩衡，因此需要更多的葡萄糖來維持血糖平衡，而與泌乳相關的葡萄糖利用率較低，這也在一定程度上解釋了高溫引起的泌乳量下降[22, 48-50]。

2 母豬溫熱環境調控技術

緩解母豬高溫熱應激是一項系統工作，除了通過豬舍設計與環境建設、合理的飼養管理技術、適宜的保健預防等[51-55]基礎措施以外，亦可配合蒸發冷卻降溫、水冷覆蓋降溫、地板降溫等舍內溫度調控技術，使高溫環境對母豬生產繁殖性能產生的不利影響最小化。

2.1 豬舍整體降溫技術

豬舍整體降溫通常采用通風降溫、蒸發降溫兩種方式。通風降溫分為自然通風和機械通風，自然通風受氣候環境影響顯著，在炎熱潮濕的南方地區，其降溫效率受到限制；機械通風常應用于大型密閉性養豬場，以負壓通風為主，但存在通風死角或局部溫度過高的區域[56]。蒸發降溫包括濕簾風機降溫、噴淋降溫、噴霧降溫等，濕簾風機降溫系統由于其設備構造簡單、降溫速度快、穩定耐用等優勢，目前廣泛應用于我國大部分密閉式豬舍[57-60]。

濕簾-風機降溫系統由特種紙質多孔濕簾、低壓大流量軸流風機、水循環系統及控制裝置組成，濕簾、風機分別安裝在畜禽舍的兩端，風機抽風時造成舍內負壓，迫使舍外未飽和的空氣流經濕潤的多孔濕簾，引起水分蒸發吸收大量潛熱，降低進入舍內的空氣溫度，從而達到降低舍內溫度的目的。豬由于汗腺不發達，對高溫環境更為敏感[61-62]。濕簾-風機蒸發冷卻系統可改善暴露于極端熱環境中母豬的熱舒適性，緩解熱應激。DONG等[63]對比了縱向通風、頭部垂直通風、水平通風、滴水降溫等不同降溫組合在分娩母豬舍的應用效果，結果發現縱向通風配合滴水降溫是更為有效的降溫組合。高增月等[64]就濕簾-風機系統降溫和自然通風降溫的分娩舍進行了對比試驗，結果發現，夏季濕簾風機系統能顯著降低舍內溫度（27.9℃vs 31.5℃，＜0.05），使哺乳仔豬的斷奶成活率提高6.97%。CARLAR等[65]研究了濕簾-風機系統妊娠舍舍內母豬的生產性能及舍內溫濕指數，與無降溫系統相比，濕簾-風機系統顯著降低母豬斷奶至發情間隔時間（5.29d vs 4.53d，＜0.05），顯著提高斷奶時母豬背膘厚（15.55mm vs 17.86mm，＜0.05），顯著提高了仔豬初生重（＜0.05），這與Liao等[66]的觀點一致；試驗期間有降溫系統的豬舍舍內溫濕指數平均值（77.52）顯著低于（＜0.05）無降溫系統豬舍（79.67）。該結果與BLOEMHOF等[67]的研究結果一致，表明濕簾-風機降溫系統可顯著改善舍內溫熱環境和提高母豬后續的生產性能。KIEFER等[68-69]使用CFD方法對分娩母豬舍濕簾降溫系統進行評估，指出該系統在風速、溫度和相對濕度等指標的均勻性方面需要進一步優化。

2.2 豬舍局部降溫技術

豬舍局部降溫主要是針對豬只躺臥區地板、兩側豬欄、豬欄上方等區域進行溫度調控。局部降溫適用于開放舍和有通風死角的密閉舍，局部小環境溫度調控方法設備簡單、節能高效、氣流容易組織、溫控易于實現[18]。常用的豬舍局部降溫技術有冷水覆蓋地板或豬欄、噴氣嘴冷卻降溫等。

2.2.1 風管噴氣嘴蒸發冷卻系統 通過組織氣流，增加動物活動區風速，是緩解豬只熱應激的有效手段之一[70-71]，風管噴氣嘴蒸發冷卻系統即利用這一方式對豬舍局部降溫，以達到緩解母豬熱應激的目的。該系統由風管、濕墊、風機及控制系統組成。分娩豬舍一端外墻安裝連接著主風管的蒸發冷卻墊，經過濕墊的冷空氣由軸流風機送入主風管進入舍內，主風管由兩個獨立的支風管組成，每個支管服務兩排分娩欄，每個分娩欄上方有獨立的末端噴氣嘴使空氣到達豬脖頸區域，推薦流量為120m3·h-1[72]，當舍內溫度高于20℃時系統自動開啟[73]。

PERIN等[73]人研究了傳統濕簾溫度控制系統（TTCS）和風管噴氣嘴蒸發冷卻系統（ESCS）對泌乳母豬直腸溫度、采食量、失重及其仔豬體重的影響。結果顯示，與TTCS組相比，ESCS組母豬直腸溫度顯著降低（＜0.05），失重顯著下降（5.3% vs 2.2%，＜0.05），斷奶至發情間隔顯著縮短（10.9 d vs 7.0 d，＜0.05），采食量顯著增加（4.8 kg·d-1vs 5.8 kg·d-1，＜0.05），窩產仔數顯著增加（10.9頭vs 12.0頭，=0.095），采食量的變化與RENAUDEAU等[74]的研究結果一致，溫度通過影響母豬體重間接影響其斷奶至發情間隔[75]。JUSTINO等[76]比較了傳統機械通風與風管蒸發冷卻系統在分娩母豬上的降溫效果，結果發現，與傳統機械通風降溫相比，風管蒸發冷卻降溫可使母豬頭部上方區域干球溫度降低2.09℃（＜0.05），母豬體表溫度降低0.47℃（＜0.05），呼吸頻率降低25.4%（＜0.05）。相比于傳統溫度控制系統，風管蒸發冷卻系統的使用對于增加母豬熱損耗作用顯著，能緩解高溫對母豬體溫調節的負面影響，使母豬采食量顯著提高、體重損失減少、繁殖性能提高，母豬和仔豬生產性能均明顯改善。

2.2.2 冷水覆蓋降溫 冷水覆蓋降溫是在豬欄上方及側面鋪設冷水管，通過熱傳導及輻射作用，使豬欄相鄰單元達到適宜的溫度環境。PANG等[77-78]研發了一套冷水覆蓋降溫系統（WCCs），并探究了該系統對高溫高濕氣候下分娩母豬生理和生產性能參數的影響。WCCs由鋼結構框架、鍍鋅鋼制水管和鋁制遮蓬組成，水管沿長度方向安裝于拱形頂內側，兩端為2根豎直水管（其中相鄰單元間共用1根豎直管），3單元為一組，進出水口分別位于該組WCC兩側，拱頂上部覆蓋聚乙烯泡沫隔熱。研究結果顯示，當舍內環境溫度為37℃時，系統可以將母豬躺臥區溫度降低3.0—4.5℃，在舍內溫度小于35℃時保持適宜的溫度范圍（25—30℃）；當環境溫度低于30℃時，分娩母豬的呼吸頻率和體表溫度在處理組（WCCs）和對照組（灑水冷卻）之間無顯著差異，但當溫度升高到30℃以上時差異顯著（＜0.05）；對照組母豬在炎熱天氣時飲水量較多，但采食量顯著少于處理組的母豬（＜0.01）。室內空氣溫度為34.3℃時，在WCCs的作用下，母豬躺臥區的黑球溫度在有母豬和無母豬的情況下分別可降溫4.8℃和5.4℃；母豬躺臥區的溫降幅度與系統進出水溫度差成正比，在一定范圍內增加水流速度可提高降溫效率[79]。李偉等[80]研究了冷水覆蓋降溫對母豬躺臥行為的影響，結果發現，當豬舍溫度大于31℃時，75%的母豬選擇在冷水覆蓋豬床內躺臥，且該比例隨著環境溫度升高而增加。因此，水冷覆蓋降溫系統的使用可以減輕典型炎熱氣候期間分娩母豬的熱應激，具有提高母豬生產性能的實用價值。

2.2.3 豬舍地板局部降溫 豬舍地板局部降溫是指以地下水或壓縮冷卻水為媒介、在豬的躺臥區地板下部鋪設水管的一種傳導降溫方式。據報道，豬只一天中有79%的時間（約19 h）都在休息，這意味著大部分豬只的身體長時間與地面接觸[81]，因此，高溫季節采取地板降溫是一種有效緩解豬只熱應激的方式。李保明[82]等研發了一種利用地下水對豬舍地板局部降溫的技術，試驗發現環境溫度34℃時該技術可將母豬躺臥區域溫度控制在22—26℃，與SHI等的結果一致[83]。BARBARI等[84]發現在高溫季節母豬同時使用地板降溫和氣流降溫更為舒適。SILVA等[85-86]研究發現，采用地板降溫（地板溫度27.6℃）母豬的采食量（6.47kg·d-1vs 5.61kg·d-1，＜0.01）、斷奶時仔豬體重（6.42kg/頭 vs 5.30 kg/頭）顯著高于對照組（地板溫度35.8℃）；地板降溫組母豬的直腸溫度、體表溫度和呼吸率均更低（＜0.01），側臥時間更短（＜0.01）、哺乳時間更長（＜0.05）、采食時間更長（＜0.01）。CABEZON等[87-88]初步評估了降溫地板的3種水流速度（0.25、0.55和0.85 L·min-1）對高溫環境下（環境溫度35.3℃，相對濕度57.8%）分娩母豬的影響，高水流速度（0.85 L·min-1）時，分娩母豬各項指標最佳（呼吸率為31，直腸溫度為39.1℃，散熱率為320.7w）。地板降溫方式可增加哺乳母豬的日采食量，減少失重，縮短斷奶至發情間隔，同時可改善母豬哺乳行為，增加泌乳量。

3 結語

母豬作為生豬養殖場的核心豬群，適宜溫熱環境的控制至關重要，這有利于保障母豬健康狀況，從而提高其生產和繁殖性能。蒸發冷卻降溫、水冷覆蓋降溫、地板降溫等溫熱環境調控技術，在實際生產中，除了濕簾-風機蒸發降溫系統在規模豬場中利用率較高，其余幾種技術雖然降溫效果明顯、運行能耗低，但受成本、管理等因素限制，尚未被推廣應用，還有待進一步結合實際進行優化應用。本文所述母豬溫熱環境調控技術僅為該領域內典型部分，以期為我國生豬養殖場母豬溫熱環境調控實施提供參考。

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（責任編輯 林鑒非）

Effects of Ambient Temperature on Production Performance of Sows and Regulatory Techniques

ZENG YaQiong1, WANG Hao1,2, LIU ZuoHua1, LI Shuang1, PU ShiHua1,2, LONG DingBiao1,2

(1;2Ministry of Agriculture Southwest facility aquaculture engineering scientific observation experimental station, Chongqing 402460)

The pig industry is one of the mainstay industries of China's agriculture and rural economy. As the core component of pig farms, production performance of sows are the key factors for determining the economic benefits of pig farms. China is the largest pig breeding country in the world, and the number of breeding sows and commercial pigs are more than 50% of the world’s total. However, compared with developed countries, sows feeding management level is low in our country, and there is still a large gap in production performance. The performance of sows in practical production is affected by many factors, including nutrient intake, body characteristics, feeding environment, parity of sows, etc. Thermal environment is one of the major factors affecting the health and production performance of sows. The warm environment consists of temperature, relative humidity, air flow, radiation, and heat transfer. These factors work together on the animal to make them feel cold or hot and comfortable or not. The suitable thermal environment is conducive to ensuring the sows’ health and improving their production performance. Conversely, the unsuitable warm environment will cause heat stress in sows, destroy the body heat balance, and even lead production stop, make the body enters a pathological state, cause illness and ultimately death. Therefore, mastering the warm environment requirements of sows and adopting effective control measures are essential to improve the performance of sows and the economic benefits of pig farms.This paper reviewed the effects of warm environment on sows and the corresponding regulation techniques, aiming to provide theoretical basis and technical support for the regulation of thermal environment in pig production and management in China. (1) The effects of the warm environment on the sow are mainly reflected in changes of behavior, physiology and production performance. In terms of behavior, sows will be thermally adjusted by changing the behavioral posture, such as increasing the lying time, reducing the standing and prone time in hot environment. Because the contact area of the sows' body surface with the ground is larger when the side is lying, and the heat dissipation of the body can be increased, but frequent changes in sows’ posture will increase the piglet death rate. In the aspect of physiology, sows will reduce metabolic heat production and increase heat dissipation by reducing feed intake, increasing respiration rate and skin blood flow during heat stress, while promoting the adrenocorticotropic hormone and cortisol in the blood of sows, thyroxine dropped and insulin sensitivity increased. These physiological changes will destroy the endocrine and energy balance of the sow, leading to early embryo death, miscarriage and milk production reduction. In terms of production performance, heat stress adversely affects the performance of sow estrus interval, litter size and lactation. Heat stress mainly affects the re-service rate and litter size at pre-pregnancy and in late pregnancy mainly affects the number of live births and stillbirths. After parturition, heat stress mainly affects the survival rate of piglets. High ambient temperature adversely affects the performance of weaned piglets by affecting the lactation of sows, and heat stress can delay the weaning-to-estrus interval by affecting the feed intake, weight loss and hormone secretion of sows. (2) Thermal environment control technology of sows mainly includes overall cooling and partial cooling of the pig house. The Pad and Fan evaporative cooling system is the representative of the overall cooling of pig house. In the system, the negative pressure inside the house is caused by the exhaust of the fan, forcing the unsaturated air outside the house to flow through the wet porous curtain, causing the evaporation of water to absorb a large amount of latent heat, thereby reducing the temperature inside pig house. The system has the advantages of simplicity and cost-effectiveness. The local cooling of the pig house is mainly for the temperature control of the lying area floor, pig pens on both sides and upper part of the pig pens. The main methods include air duct evaporative cooling, cold water cover cooling, floor cooling, etc. These methods have the advantages of obvious cooling effect and energy saving.

sows; ambient temperature; regulation; performance

2018-04-10；

2018-07-17

“十三五”國家重點研發計劃（2016YFD0500500）、現代農業產業技術體系建設專項資金（CARS-35）、重慶市科研院所績效激勵引導專項（17422）

曾雅瓊，E-mail：zengyaqionghai@163.com。

蒲施樺，E-mail：opertion5@163.com。通信作者龍定彪，E-mail：longjuan880@163.com